wi - wireless & rf magazine: may, 2014

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Wireless GaN Technology

Basics of FTT

Interview with Prof. Joel Dawson, CTO & Founder of Eta Devices

Eta Devices’ founder on how their state-of-the-art technology will enhance LTE-enabled devices

May 2014May 2014

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For the launch of the Tiva C Series Connected LaunchPad, TI has partnered with Exosite, mentioned briefly above, to provide easy access to the LaunchPad from the Internet. The LaunchPad takes about 10 minutes to set up and you can immediately interact with it across the Internet and do things like turn an LED on and off remotely from the website and see the reported temperature as well. It can also display approximate geographic location based on the assigned IP address and display a map of all other connected LaunchPad owners if they are active and plugged-in to Exosite. “In addition, it supports a basic game by enabling someone to interface to the Connected LaunchPad through a serial port from a terminal while someone else is playing with them through their browser. It is basically showing how you can interact remotely with this product and a user even if you are across the globe,” Folkens explained.

START DEVELOPING

The Tiva C Series Connected LaunchPad is shipping now and the price is right; at $19.99 USD, it is less than half the price of other Ethernet-ready kits. The LaunchPad comes complete with quick start and user guides, and ample online support to ensure developers of all backgrounds are well equipped to begin creating cloud-based applications. “We have assembled an online support team to monitor the Engineering-to-Engineering (or E2E) Community,” Folkens said. “Along with this, you also got a free Code Composer Studio Integrated Development Environment, which allows developers to use the full capability. We also support other tool chains like Keil, IAR and Mentor Embedded.

Affordable, versatile, and easy to use, the Tiva Series Connected LaunchPad is well suited for a broad audience and promises to facilitate the expansion of ingenious IoT applications in the cloud. As Folkens concluded, “The target audiences actually are the hobbyists, students and professional engineers. A better way of looking at it is that we are targeting people with innovative ideas and trying to help them get those ideas launched into the cloud.”

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CONTENTS

4 TECH ARTICLEBack to Basics: Going from FFTs to

Spectrum Analysis

3

6COVER INTERVIEW

Interview with Joel DawsonCTO & Founder of Eta Devices12

18 TECH ARTICLEWearable Technology:

The Hidden Pitfall in Your Design

BACK TO BASICS:What is an FFT?

The theory behind FFTs makes an assumption, which is that the time-domain signal being transformed into a frequency-domain spectrum is of infinite duration. Obviously this is not achievable, so the compromise between theory and practice is to view the time-domain signal as consisting of an infinite series of replicas of itself.

In using FFT on a time-domain signal, what’s really happening is that the signal is being separated out into its constituent frequency components, essentially diluting its spectral energy in some number of frequency bins corresponding to multiples of the frequency resolution Δf. The capture time, T, determines the frequency resolution of the FFT (Δf = 1/T). Meanwhile, the sampling period and record length set the maximum frequency span that can be obtained (fNyq = Δf*N/2).

All of the above could, of course, be worked out mathematically as a discrete Fourier transform. But to do so even on an eight-sample signal would involve 64 complex multiplications. A signal with 1024 samples balloons out to over 1 million multiplications.

Thus, an FFT operation on an N-point time-domain signal is comparable to passing the signal through

a comb filter consisting of a bank of N/2 filters. All of these filters have the same shape and width and are centered at N/2 discrete frequencies, meaning that there are N/2 frequency “bins.” The distance in hertz between the centering frequency of any two neighboring bins is always Δf.

The way your FFT turns out is dictated to a large extent by the “window” chosen for the operation (Table 1). The window type defines the bandwidth and shape of the bank of filters applied to the time-domain signal. The weighting functions imposed by these windows control not only the filter response shape, but also noise bandwidth and side-lobe levels. Ideally, the main lobe should be as narrow and flat as possible to effectively discriminate all spectral components; meanwhile, all side lobes should be infinitely attenuated.

You can think of choosing a window type along the lines of choosing a camera lens for a given photo. Some experimentation might be in order. As shown by the table, some windows will lend themselves better to certain signal types than others, with tradeoffs between leakage and frequency resolution.

In an earlier post, we discussed the basics of setting up a fast-Fourier transform (FFT) on an oscilloscope, and why you’d want to use an FFT to get a frequency-domain view of a time-domain signal in the first place. It might be a good idea to take a step back and dig into just what an FFT is (Figure 1).

Rectangular

Figure 1: An FFT of a 300-kHz square wave.

Table 1: FFT window types and their characteristics.

Window Type Applications & Limitations

Normally used when the signal is transient – completely contained in the time-domain window – or known to have a fundamental frequency component that is an integer multiple of the fundamental frequency of the window. Signals other than these types will show varying amounts of spectral leakage and scallop loss, corrected by selecting another type of window.

Reduce leakage and improve amplitude accuracy. However, frequency resolution is also reduced.

Reduce leakage and improve amplitude accuracy. However, frequency resolution is also reduced.

The window provides excellent amplitude accuracy with moderate reduction of leakage, but also at the loss of frequency resolution.

It reduces the leakage to a minimum, but again along with reduced frequency resolution.

Hanning (Von Hann)

Hamming

Flat Top

Blackman–Harris

David MaliniakTechnical Marketing Communication SpecialistTeledyne LeCroy

Gallium nitride (GaN) RF transistors have traditionally been depletion mode, making them difficult to

bias. High frequency enhancement mode transistors, such as the EPC8000 series eGaN FETs from EPC, have been widely available since September 2013 and enable simplified designs at RF frequencies.

Surprisingly, these commercial eGaN FETs are lower cost than LDMOS transistors today, and are in many ways superior in performance. eGaN FETs offer higher voltage capability, which leads to increased power density, higher thermal conductivity, higher drain efficiency, and lower noise figure. This allows these FETs to be designed as broadband RF devices enabling the same transistor to be used for many different frequencies and applications.

In this installment of Wi GaN, we present the RF characteristics of the EPC8000 series devices and show their implementation in a pulsed class A amplifier. The amplifier is pulsed to allow operation within the thermal operating limits of the device, since RF device power dissipation is typically on the same order of magnitude as the RF power delivered, unlike switching devices, such as the EPC8000 series, that operate well above 95 % efficiency. The EPC8000 series FETs, designed originally for switching power conversion applications, otherwise exhibit excellent RF characteristics and in conclusion will be compared with similar specified LDMOS.

Wi GaN:eGaN® FETs forClass A RF Amplifier

By Alex Lidow, CEO Efficient Power Conversion (EPC)

Q What led you to co-found ETA Devices?

The seeds were probably planted during my PhD program at Stanford. I remember being in my student cubicle when some friends I knew from college were in a venture that got acquired. For the next few months, at least on paper anyway, they were very wealthy. Being in Silicon Valley at that time (in the mid ‘90s) really got your mind going in terms of thinking about entrepreneurship.

AAfter I was offered a faculty position at MIT, someone approached me to join the founding team of a startup company. I postponed my start at MIT for a year to be

with that startup company, and I now consider this as one of my formative experiences. With a lot of doctoral processes, you are

by yourself, you do everything by yourself, and that’s just how it is supposed to be. At work, you have a team, and you could sit down and at the beginning hour, no one knows the answer to the question that you’re discussing, but in the end, everybody knows the answer. It’s not really clear how that happened, or who to assign credit to, but it was very eye opening. I learned that, from a creative engineering standpoint, it’s better to be in a team, even allowing for all the

personal frictions that are inevitable. That influenced how I ran my research group at MIT. With this startup experience in my background, I was really looking for a way to take something that I found in research and have an impact with it in the form of a startup company.

Q Tell us about your company’s flagship product and what you offer to customers.

AWe are developing two things. It turns out that for both base stations and for handsets like cellular phones, the dominant power consumer today is found in the radio

transmitter that sends radio waves out over the antenna—the power amplifier. On the base station, we have demonstrated a power amplifier that is the most efficient in the world. We are a fabless semiconductor company, so we sell chips that allow base station manufacturers to get that same result. On the handset side, we’re also actually developing a microchip that would allow people to use our concept in any of the leading smart phones. In terms of efficiency improvement, our product offers a significant advancement. The average state-of-the-art efficiency in a base station right now is around 48%. We are able to exceed 70% efficiency today. That’s a huge jump. With digital circuits, microprocessors, and computers, people are used to the idea that the IC performance is going to double every eighteen months based on Moore’s Law. But with radio and analog design, that is far from true; things do get better over time, but a jump of more than twenty percentage points in terms of efficiency is something that you just don’t see. It’s a big technological shift, and it is why we talk about our innovation being disruptive.

“Taking care of efficiency in the base stations is the single biggest thing that a major carrier can do to reduce their carbon footprint. That’s where ETAdvanced comes in.”

Wearable Technology Design

By Richard Walters – Director of Industrial Design, LS Research

The Wearable Technology industry, incorporating embedded electronics with clothing and other body-worn accessories, is producing arguably the biggest buzz this

year in the consumer electronic, health, and wellness industries. Bluetooth-based accessories are once again on a dramatic rise, with applications broadening far beyond simply transferring phone audio to an ear bud. Designers are dreaming up new ways to harness the power of the consumer’s smartphone to transmit information to and from locations on the human body, seeking to expand the usefulness of the smartphone beyond the inherent constraints caused by its form factor.

The Hidden Pitfall in your Design

RICH WALTERSRich has over 23 years of Industrial Design experience, covering a wide spectrum of product development including design research, interaction design, CAD, and prototyping. Rich has accumulated over 30 design patents and several utility and international patents. Learn more about the full breadth of LSR’s wireless product development capabilities at www.lsr.com.

FEATURED ARTICLEWi GaN? eGaN FETs for Class-A RF Amplifiers

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TECH ARTICLE

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TECH ARTICLE

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http://epc-co.com/epc/Products/eGaNFETs.aspx

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Figure 1: Photograph of an EPC8000 series eGaN FET.

Figure 2: Reference plane design for RF connection to the EPC8000 series FET.

Figure 3: Basic Class A Amplifier schematic showing transmission lines, bias Tees and matching networks.

RF Characteristic MeasurementThe EPC8000 series come in chip-scale packages (shown in Figure 1) which was not designed with RF type connections. This means an RF connection must be constructed which can be used in subsequent amplifier designs.

For the EPC8000 series devices, the design of the RF interface is based on micro strip lines [1] that taper towards the device and measurement is taken from reference planes that interface to a 50 Ω transmission line as shown in Figure 2. Due to thermal limitations, and since the device needs to be biased, pulse based testing was implemented to keep the average power dissipation of the device well below the thermal limit. In this case a 240 µs pulse was applied at a repetition rate of 10 Hz and was implemented using a specially designed controller [4] that ensured that the device remained stable and correctly biased under all test conditions. The design of the bias Tees for the amplifier must also accommodate pulse testing to ensure stable operation [5].

Class A Amplifier DesignThe s-parameters for all the EPC8000 series devices were measured and analyzed [6,7,8, and 9].

The EPC8009 [10] was chosen to design a 500 MHz class A amplifier because it yielded the highest gain for a realizable design and is rated at 65 V for wide dynamic range. The analysis revealed that this device at 500 MHz is bi-lateral and conditionally stable. To design a stable amplifier the available gain method [11] was used as it yields a matched output thereby reducing reflected energy from the output that can de-stabilize the gate.

A gain of 200 = 23 dB was chosen based on the s-parameters and stability criteria [12] and yielded the following design reflection coefficients that were used to complete the design:

S = -0.604 -0.167•i

L = -0.557 +0.458•i

To accommodate a small heat-sink, short 50 Ω transmission lines were added to the gate and drain connections. The impact of the transmission lines and bias Tee’s were compensated for in the design of the matching networks. High pass filter matching networks were chosen due to the high gain of the device at lower frequencies that can cause stability issues and have the added benefit of inherent DC blocking for the bias circuit. The complete class A amplifier schematic is shown in Figure 3.

Figure 4: Photograph of the class A amplifier based on the EPC8009 device.

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TECH ARTICLE

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Figure 1: Photograph of an EPC8000 series eGaN FET.

Figure 2: Reference plane design for RF connection to the EPC8000 series FET.

Figure 3: Basic Class A Amplifier schematic showing transmission lines, bias Tees and matching networks.

RF Characteristic MeasurementThe EPC8000 series come in chip-scale packages (shown in Figure 1) which was not designed with RF type connections. This means an RF connection must be constructed which can be used in subsequent amplifier designs.

For the EPC8000 series devices, the design of the RF interface is based on micro strip lines [1] that taper towards the device and measurement is taken from reference planes that interface to a 50 Ω transmission line as shown in Figure 2. Due to thermal limitations, and since the device needs to be biased, pulse based testing was implemented to keep the average power dissipation of the device well below the thermal limit. In this case a 240 µs pulse was applied at a repetition rate of 10 Hz and was implemented using a specially designed controller [4] that ensured that the device remained stable and correctly biased under all test conditions. The design of the bias Tees for the amplifier must also accommodate pulse testing to ensure stable operation [5].

Class A Amplifier DesignThe s-parameters for all the EPC8000 series devices were measured and analyzed [6,7,8, and 9].

The EPC8009 [10] was chosen to design a 500 MHz class A amplifier because it yielded the highest gain for a realizable design and is rated at 65 V for wide dynamic range. The analysis revealed that this device at 500 MHz is bi-lateral and conditionally stable. To design a stable amplifier the available gain method [11] was used as it yields a matched output thereby reducing reflected energy from the output that can de-stabilize the gate.

A gain of 200 = 23 dB was chosen based on the s-parameters and stability criteria [12] and yielded the following design reflection coefficients that were used to complete the design:

S = -0.604 -0.167•i

L = -0.557 +0.458•i

To accommodate a small heat-sink, short 50 Ω transmission lines were added to the gate and drain connections. The impact of the transmission lines and bias Tee’s were compensated for in the design of the matching networks. High pass filter matching networks were chosen due to the high gain of the device at lower frequencies that can cause stability issues and have the added benefit of inherent DC blocking for the bias circuit. The complete class A amplifier schematic is shown in Figure 3.

Figure 4: Photograph of the class A amplifier based on the EPC8009 device.

1010

Experimental ResultsAn experimental class A amplifier was built, as shown in Figure 4, and connected to a pulse controller for testing. The amplifier was tested to determine the 1 dB compression point which is shown in Figure 5 for two current bias conditions. With 500 mA drain bias current, the amplifier has a 1 dB compression point at 40.6 dBm (11.6 W) output power, where the power gain is 20.6 dB with drain efficiency of 57.4 % as shown in Figure 6. At a drain bias current of 250 mA, the amplifier has a 1 dB compression at 38.4 dBm (6.96 W) output power, where the power gain is 19.3 dB with drain efficiency of 45.9 %. Comparison with LDMOSWe can now compare the RF performance of the eGaN FET against state-of-the-art LDMOS FETs with similar characteristics. Since the eGaN FET is not an RF device, the comparison will focus on the differences with respect to RF designs. The characteristics that will be compared are power gain, linearity (1 dB compression) and drain efficiency. The LDMOS devices selected are ST’s PD55015-E and Freescale’s MRF1518N, both of which have comparable power capability at 500 MHz. The comparison data between the GaN FET and LDMOS FETs is given in Table 1:

Table 1 shows that the EPC8009 has higher gain than either LDMOS device while operating at a higher voltage with comparable drain efficiency despite having a higher bias power and not being internally tuned for operation at 500 MHz. The capacitances of the EPC8009 are also much lower than either LDMOS FET ensuring reduced matching impedance transformation.

SummaryA pulsed class A RF amplifier design was presented using the EPC8009 eGaN FET. An amplifier was constructed, tested and various measurements made to confirm RF power performance. The EPC8009 eGaN FET was originally designed to be a high frequency switching device, but it also exhibits excellent RF characteristics with stable gain in excess of 20 dB and a drain efficiency approaching 60% at the 1dB compression point. The EPC8009 compares favorably to commercially available LDMOS devices despite not being internally tuned for operation at 500 MHz and even allows reduced impedance matching transformation due to its lower capacitances. The higher voltage rating of the eGaN FET has also increased its 1dB compression point over the LDMOS devices.

Figure 5: Measured 1 dB compression point for the EPC8009 based RF amplifier with 30 V drain bias voltage and 250 mA

and 500 mA drain bias currents while operating at 500 MHz.

Figure 6: Measured Gain and Drain efficiency for the EPC8009 based RF amplifier with 30 V drain bias voltage and 250 mA


Table 1

eGaN® FET is a registered trademark of Efficient Power Conversion Corporation.

Parameter EPC8009 (500 mA) EPC8009 (250 mA) PD55015-E MRF1518N

Output Power 11.6 W 6.96 W 15 W 8 W

1 dB Gain 20.6 dB 19.3 dB 14 dB 13 dB

Drain Efficiency 57.4 % 45.9 % 55 % 60 %

Rated Voltage 65 V 65 V 40 V 40 V

Bias Voltage 30 V 30 V 12.5 V 12.5 V

Bias Current 500 mA 250 mA 150 mA 150 mA

Input Capacitance CISS 47 pF at 32.5 V 47 pF at 32.5 V 89 pF at 32.5 V 66 pF at 12.5 V

Reverse Capacitance CRSS 0.4 pF at 32.5 V 0.4 pF at 32.5 V 6.5 pF at 12.5 V 4.5 pF at 12.5 V

Output Capacitance COSS 17 pF at 32.5 V 17 pF at 32.5 V 60 pF at 12.5 V 33 pF at 12.5 V

References[1] I. J. Bahl, D. K. Trivedi, “A Designer’s Guide to Microstrip Line,”

Microwaves, May 1977, pg. 174 – 182.[2] G.F. Engen, C.A. Hoer,“Thru-Reflect-Line: An Improved Technique

for Calibrating the Dual Six-Port Automatic Network Analyzer,” IEEE Trans. Microwave Theory and Techniques, December 1979.

[3] J. Fleury, O. Bernard, “Designing and Characterizing TRL Fixture Calibration Standards for Device Modeling,” Applied Microwave & Wireless Technical Note 13, 2001, ISSN 1075-0207, pg 26 – 55.

[4] M.A. de Rooij, J.T. Strydom, “Method for Bias Control of a Class A Power RF Amplifier”, patent pending, September 2013.

[5] C. Baylis, L. Dunleavy, W. Clausen, ”Design of Bias Tees for a Pulsed-Bias, Pulsed-RF Test System using Accurate Component Models,” Microwave Journal, Volume 49, Issue 10, October 2006, pg. 68 – 75.

[6] M.D. Hodge, R. Vetury, J. Shealy, R. Adams, “A Robust AlGaN/GaN HEMT Technology for RF Switching Applications,” IEEE Symposium on Compound Semiconductor Integrated Circuit (CSICS), October 2011, pg 1 - 4

[7] D. M. Pozar, “Microwave Engineering,” Third Edition 2005, J. Wiley ISBN 0-471-44878-8

[8] G. Gonzales, “Microwave Transistor Amplifiers,” Second Edition 1997, Prentice Hall ISBN 0-13-254335-4

[9] R. C. Hejhall, “RF Small Signal Design Using Two-Port Parameters,” Motorola application note AN215A, 1993.

[10] Efficient Power Conversion, EPC8009 datasheet, http://epc-co.com/epc/Products/eGaNFETs.aspx

[11] K. Payne, “Practical RF Amplifier Design Using the Available Gain Procedure and the Advanced Design System EM/Circuit Co-Simulation Capability,” Agilent Technologies White Paper 5990-3356EN, 2008, www.agilent.com

[12] J. M. Rollett, “Stability and Power-Gain Invariants of Linear Twoports,” IRE Transactions on Circuit Theory, Vol. 9, Issue 1, March 1962, pp 29 – 32

[13] S. J. Orfanidis, “Electromagnetic Waves and Antennas,” http://www.ece.rutgers.edu/~orfanidi/ewa/

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TECH ARTICLE

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Experimental ResultsAn experimental class A amplifier was built, as shown in Figure 4, and connected to a pulse controller for testing. The amplifier was tested to determine the 1 dB compression point which is shown in Figure 5 for two current bias conditions. With 500 mA drain bias current, the amplifier has a 1 dB compression point at 40.6 dBm (11.6 W) output power, where the power gain is 20.6 dB with drain efficiency of 57.4 % as shown in Figure 6. At a drain bias current of 250 mA, the amplifier has a 1 dB compression at 38.4 dBm (6.96 W) output power, where the power gain is 19.3 dB with drain efficiency of 45.9 %. Comparison with LDMOSWe can now compare the RF performance of the eGaN FET against state-of-the-art LDMOS FETs with similar characteristics. Since the eGaN FET is not an RF device, the comparison will focus on the differences with respect to RF designs. The characteristics that will be compared are power gain, linearity (1 dB compression) and drain efficiency. The LDMOS devices selected are ST’s PD55015-E and Freescale’s MRF1518N, both of which have comparable power capability at 500 MHz. The comparison data between the GaN FET and LDMOS FETs is given in Table 1:

Table 1 shows that the EPC8009 has higher gain than either LDMOS device while operating at a higher voltage with comparable drain efficiency despite having a higher bias power and not being internally tuned for operation at 500 MHz. The capacitances of the EPC8009 are also much lower than either LDMOS FET ensuring reduced matching impedance transformation.

SummaryA pulsed class A RF amplifier design was presented using the EPC8009 eGaN FET. An amplifier was constructed, tested and various measurements made to confirm RF power performance. The EPC8009 eGaN FET was originally designed to be a high frequency switching device, but it also exhibits excellent RF characteristics with stable gain in excess of 20 dB and a drain efficiency approaching 60% at the 1dB compression point. The EPC8009 compares favorably to commercially available LDMOS devices despite not being internally tuned for operation at 500 MHz and even allows reduced impedance matching transformation due to its lower capacitances. The higher voltage rating of the eGaN FET has also increased its 1dB compression point over the LDMOS devices.

Figure 5: Measured 1 dB compression point for the EPC8009 based RF amplifier with 30 V drain bias voltage and 250 mA


Figure 6: Measured Gain and Drain efficiency for the EPC8009 based RF amplifier with 30 V drain bias voltage and 250 mA


Table 1

eGaN® FET is a registered trademark of Efficient Power Conversion Corporation.

Parameter EPC8009 (500 mA) EPC8009 (250 mA) PD55015-E MRF1518N

Output Power 11.6 W 6.96 W 15 W 8 W

1 dB Gain 20.6 dB 19.3 dB 14 dB 13 dB

Drain Efficiency 57.4 % 45.9 % 55 % 60 %

Rated Voltage 65 V 65 V 40 V 40 V

Bias Voltage 30 V 30 V 12.5 V 12.5 V

Bias Current 500 mA 250 mA 150 mA 150 mA

Input Capacitance CISS 47 pF at 32.5 V 47 pF at 32.5 V 89 pF at 32.5 V 66 pF at 12.5 V

Reverse Capacitance CRSS 0.4 pF at 32.5 V 0.4 pF at 32.5 V 6.5 pF at 12.5 V 4.5 pF at 12.5 V

Output Capacitance COSS 17 pF at 32.5 V 17 pF at 32.5 V 60 pF at 12.5 V 33 pF at 12.5 V

References[1] I. J. Bahl, D. K. Trivedi, “A Designer’s Guide to Microstrip Line,”

Microwaves, May 1977, pg. 174 – 182.[2] G.F. Engen, C.A. Hoer,“Thru-Reflect-Line: An Improved Technique

for Calibrating the Dual Six-Port Automatic Network Analyzer,” IEEE Trans. Microwave Theory and Techniques, December 1979.

[3] J. Fleury, O. Bernard, “Designing and Characterizing TRL Fixture Calibration Standards for Device Modeling,” Applied Microwave & Wireless Technical Note 13, 2001, ISSN 1075-0207, pg 26 – 55.

[4] M.A. de Rooij, J.T. Strydom, “Method for Bias Control of a Class A Power RF Amplifier”, patent pending, September 2013.

[5] C. Baylis, L. Dunleavy, W. Clausen, ”Design of Bias Tees for a Pulsed-Bias, Pulsed-RF Test System using Accurate Component Models,” Microwave Journal, Volume 49, Issue 10, October 2006, pg. 68 – 75.

[6] M.D. Hodge, R. Vetury, J. Shealy, R. Adams, “A Robust AlGaN/GaN HEMT Technology for RF Switching Applications,” IEEE Symposium on Compound Semiconductor Integrated Circuit (CSICS), October 2011, pg 1 - 4

[7] D. M. Pozar, “Microwave Engineering,” Third Edition 2005, J. Wiley ISBN 0-471-44878-8

[8] G. Gonzales, “Microwave Transistor Amplifiers,” Second Edition 1997, Prentice Hall ISBN 0-13-254335-4

[9] R. C. Hejhall, “RF Small Signal Design Using Two-Port Parameters,” Motorola application note AN215A, 1993.

[10] Efficient Power Conversion, EPC8009 datasheet, http://epc-co.com/epc/Products/eGaNFETs.aspx

[11] K. Payne, “Practical RF Amplifier Design Using the Available Gain Procedure and the Advanced Design System EM/Circuit Co-Simulation Capability,” Agilent Technologies White Paper 5990-3356EN, 2008, www.agilent.com

[12] J. M. Rollett, “Stability and Power-Gain Invariants of Linear Twoports,” IRE Transactions on Circuit Theory, Vol. 9, Issue 1, March 1962, pp 29 – 32

[13] S. J. Orfanidis, “Electromagnetic Waves and Antennas,” http://www.ece.rutgers.edu/~orfanidi/ewa/

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ETA Devices is a fabless semiconductor company based out of Cambridge, Massachusetts. The

company's breakthrough ETAdvanced power management technology enables mobile devices to be extremely power efficient with significant reductions in base station cabinets and breakdown rates. The technology offers handset manufacturers substantial benefits in power saving and multi-band communication for LTE-enabled devices. The impact this has will not only benefit the mobile market, but will contribute to reducing the harmful impact of carbon emissions on our planet by enabling wireless communication that will be the equivalent of removing 7 million cars off the road.

We spoke with Professor Joel Dawson, Founder and CTO of Eta Devices, about the company's successful flagship product, the unique ways in which they are pushing the envelope in the mobile market, and about the beneficial environmental side-effects their new product offers.


THE CHIP

THE MOBILE

THAT WILLCHANGE

MARKET

COVER INTERVIEW

13

ETA Devices is a fabless semiconductor company based out of Cambridge, Massachusetts. The

company's breakthrough ETAdvanced power management technology enables mobile devices to be extremely power efficient with significant reductions in base station cabinets and breakdown rates. The technology offers handset manufacturers substantial benefits in power saving and multi-band communication for LTE-enabled devices. The impact this has will not only benefit the mobile market, but will contribute to reducing the harmful impact of carbon emissions on our planet by enabling wireless communication that will be the equivalent of removing 7 million cars off the road.

We spoke with Professor Joel Dawson, Founder and CTO of Eta Devices, about the company's successful flagship product, the unique ways in which they are pushing the envelope in the mobile market, and about the beneficial environmental side-effects their new product offers.


THE CHIP

THE MOBILE

THAT WILLCHANGE

MARKET

14











COVER INTERVIEW

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Q What is the next step for your company in terms of how far you have pushed the envelope? How much room is there left for improvement?

A We are a new company and a new player on the scene. We came on board, and we’re fighting our way into the ecosystem. Just to give you an idea, if you buy a

transistor from a company, they don’t actually give you a full datasheet; what they give you is, if you take this transistor and use it in our reference design, this is the kind of performance that you’re going to get. The point I am making is that many of the components and parts that we have used have been optimized for the incumbent technologies. So in terms of where we go from here, things really take off

when we get industry acceptance for ETAdvanced. Today we have to fight our way into the ecosystem. But once

your technology is accepted, the ecosystem starts to come to you. If you are a PA module manufacturer,

why wouldn’t you optimize your part to work with the best technology? Of course you would.

Q Tell us about the energy savings and what this means for all the power that is being consumed by mobile devices. How much savings are we looking at?

“In terms of efficiency improvement, our product offers a significant advancement. The average state-of-the-art efficiency in a base station right now is around 48%. We are able to exceed 70% efficiency today.”

A Deployed throughout the mobile network, we’re talking about forty percent reduction in energy. To put this in perspective, if you go on the websites of big telecom

companies, what you notice is that they all have some sort of environmental statement: “here’s what we’re doing to reduce our carbon footprint.” The protocol is to have a big, gaudy goal of reducing emissions by, say, twenty percent, and then list of all the things that are being done. Some common examples are “we use teleconferencing instead of flying our executives to meetings,” or “we’ve got a fleet of ten thousand vehicles and we commit to making half of those hybrids.” According to their own math, steps such as these reduce the carbon footprint of a major carrier by a fraction of a percent. Taking care of efficiency in the base stations is the single biggest thing that a major carrier can do to reduce their carbon footprint. That’s where ET comes in.

Q What’s the culture like in ETA Devices?

A We work very hard to cultivate group creativity. There’s not a lot of concern for who came up with what idea, or who gets credit more. Whenever I try to recruit someone,

a big part of my pitch is, “We are trying to go to the moon.” The types of people that are in our team now really are very good at what they do and they are attracted to applying their skills in the service of a shared vision. It’s what sustains us during the inevitable ups and down of the startup life—it’s quite a ride.

“Eta Devices has a firm commitment to producing environmentally friendly products. ETAdvanced is made exclusively from non-toxic silicon, which is able to achieve the same efficiencies without the harmful impact on the environment.”

COVER INTERVIEW

17

Q What is the next step for your company in terms of how far you have pushed the envelope? How much room is there left for improvement?

A We are a new company and a new player on the scene. We came on board, and we’re fighting our way into the ecosystem. Just to give you an idea, if you buy a

transistor from a company, they don’t actually give you a full datasheet; what they give you is, if you take this transistor and use it in our reference design, this is the kind of performance that you’re going to get. The point I am making is that many of the components and parts that we have used have been optimized for the incumbent technologies. So in terms of where we go from here, things really take off

when we get industry acceptance for ETAdvanced. Today we have to fight our way into the ecosystem. But once

your technology is accepted, the ecosystem starts to come to you. If you are a PA module manufacturer,

why wouldn’t you optimize your part to work with the best technology? Of course you would.

Q Tell us about the energy savings and what this means for all the power that is being consumed by mobile devices. How much savings are we looking at?

“In terms of efficiency improvement, our product offers a significant advancement. The average state-of-the-art efficiency in a base station right now is around 48%. We are able to exceed 70% efficiency today.”

A Deployed throughout the mobile network, we’re talking about forty percent reduction in energy. To put this in perspective, if you go on the websites of big telecom

companies, what you notice is that they all have some sort of environmental statement: “here’s what we’re doing to reduce our carbon footprint.” The protocol is to have a big, gaudy goal of reducing emissions by, say, twenty percent, and then list of all the things that are being done. Some common examples are “we use teleconferencing instead of flying our executives to meetings,” or “we’ve got a fleet of ten thousand vehicles and we commit to making half of those hybrids.” According to their own math, steps such as these reduce the carbon footprint of a major carrier by a fraction of a percent. Taking care of efficiency in the base stations is the single biggest thing that a major carrier can do to reduce their carbon footprint. That’s where ET comes in.

Q What’s the culture like in ETA Devices?

A We work very hard to cultivate group creativity. There’s not a lot of concern for who came up with what idea, or who gets credit more. Whenever I try to recruit someone,

a big part of my pitch is, “We are trying to go to the moon.” The types of people that are in our team now really are very good at what they do and they are attracted to applying their skills in the service of a shared vision. It’s what sustains us during the inevitable ups and down of the startup life—it’s quite a ride.

“Eta Devices has a firm commitment to producing environmentally friendly products. ETAdvanced is made exclusively from non-toxic silicon, which is able to achieve the same efficiencies without the harmful impact on the environment.”

1818







19

TECH ARTICLE

19







2020

CONSUMERS ARE LEFT WANTING MORE

Whether you realize it or not, that beautiful new Samsung or iPhone’s sexy shape is actually keeping you from doing more. It is becoming a pocket computer that may someday stay in your pocket or eventually “disappear” altogether, as it is integrated onto our bodies or into the things we wear. This trend towards a better, more natural user experience has been slow in coming to fruition; after all, mobile phones have been around for over 20 years and we still primarily grip them in our hands and hold them to our faces. That being said, this trend will keep marching forward as consumers crave better solutions in terms of usability.

So the market is opening before your eyes! Your company may be looking to leverage this trend and add a unique differentiator to your products or to improve your product’s performance. Sounds simple enough, right? Reality is, the product-to-market roadside is quickly becoming littered with failed or abandoned Wearable Tech products. These products may perform technically but are housed in a design that you wouldn’t be caught dead walking out of the house wearing. On the other hand, other flawed concepts may look and sound good in theory, but simply

don’t have the performance or reliability the user expects. I can have the sleekest looking tip calculator on the planet, but if it doesn’t correctly multiply my dinner bill by 20%, I won’t be carrying it around for very long.

In a nutshell, products such as these have only ensured their hammock is securely tied to one tree, not both.

TYING YOUR WEARABLE TECH “HAMMOCK” TO TWO TREES

So what ultimately makes a successful product concept for the Wearable Technology space? We find it easiest to think of a Wearable Tech product as a hammock which must be secured to two strong, sturdy trees. After all, a hammock tied up on only one end won’t offer a very enjoyable nap! To ensure your Wearable Tech is something the end user will ultimately value, purchase, and use, it’s helpful to think of two “Must Have’s” for product success. These are the “trees” that you must be securely tied to:• Makes the consumer react with, “That

looks like something I would wear, it looks useful and makes my life easier!”

• Intuitively and reliably performs the function(s) I expect it to. In other words, the technology works!

It sounds straight-forward enough. So why are so many products destined to end up joining the ranks of Wearable Tech products that missed the mark? Commonly, the development team either fails to realize, or realizes too late, that when bringing the person and their technology closer and closer together, the two key design elements, namely Industrial Design and Wireless Design, are interdependent and must be approached holistically. The following example will hopefully shed more light on this point. HOLISTIC APPROACH TO INDUSTRIAL AND WIRELESS DESIGN

At the heart of the performance of nearly every product that incorporates wireless communication is the antenna. A well-designed antenna ensures the best possible range and data throughput possible for the system. However, the antenna does not exist in a vacuum, it lives right here in the real world. And everything from the composition, shape, and size of the enclosure it’s placed inside of, to the proximity it has to the human body dramatically impacts the effectiveness of that antenna. In other words, if the form factor and design of the physical product are decided independently of your wireless design, you may have painted your RF/Antenna designer into a corner and the only way out is a complete re-design.

“The key for

success in designing

Wearable Tech is

to approach both

the Industrial

and Wireless

Technology Design

methodologies

holistically.”

WHAT’S AT RISK IF INDUSTRIAL DESIGN AND WIRELESS DESIGN ARE NOT ADDRESSED COLLECTIVELY?

• Multiple design and prototype iterations• Product development deadlines broken and budgets overrun• A product that your customers simply don’t want

21

TECH ARTICLE

21

CONSUMERS ARE LEFT WANTING MORE

Whether you realize it or not, that beautiful new Samsung or iPhone’s sexy shape is actually keeping you from doing more. It is becoming a pocket computer that may someday stay in your pocket or eventually “disappear” altogether, as it is integrated onto our bodies or into the things we wear. This trend towards a better, more natural user experience has been slow in coming to fruition; after all, mobile phones have been around for over 20 years and we still primarily grip them in our hands and hold them to our faces. That being said, this trend will keep marching forward as consumers crave better solutions in terms of usability.

So the market is opening before your eyes! Your company may be looking to leverage this trend and add a unique differentiator to your products or to improve your product’s performance. Sounds simple enough, right? Reality is, the product-to-market roadside is quickly becoming littered with failed or abandoned Wearable Tech products. These products may perform technically but are housed in a design that you wouldn’t be caught dead walking out of the house wearing. On the other hand, other flawed concepts may look and sound good in theory, but simply

don’t have the performance or reliability the user expects. I can have the sleekest looking tip calculator on the planet, but if it doesn’t correctly multiply my dinner bill by 20%, I won’t be carrying it around for very long.

In a nutshell, products such as these have only ensured their hammock is securely tied to one tree, not both.

TYING YOUR WEARABLE TECH “HAMMOCK” TO TWO TREES

So what ultimately makes a successful product concept for the Wearable Technology space? We find it easiest to think of a Wearable Tech product as a hammock which must be secured to two strong, sturdy trees. After all, a hammock tied up on only one end won’t offer a very enjoyable nap! To ensure your Wearable Tech is something the end user will ultimately value, purchase, and use, it’s helpful to think of two “Must Have’s” for product success. These are the “trees” that you must be securely tied to:• Makes the consumer react with, “That

looks like something I would wear, it looks useful and makes my life easier!”

• Intuitively and reliably performs the function(s) I expect it to. In other words, the technology works!

It sounds straight-forward enough. So why are so many products destined to end up joining the ranks of Wearable Tech products that missed the mark? Commonly, the development team either fails to realize, or realizes too late, that when bringing the person and their technology closer and closer together, the two key design elements, namely Industrial Design and Wireless Design, are interdependent and must be approached holistically. The following example will hopefully shed more light on this point. HOLISTIC APPROACH TO INDUSTRIAL AND WIRELESS DESIGN

At the heart of the performance of nearly every product that incorporates wireless communication is the antenna. A well-designed antenna ensures the best possible range and data throughput possible for the system. However, the antenna does not exist in a vacuum, it lives right here in the real world. And everything from the composition, shape, and size of the enclosure it’s placed inside of, to the proximity it has to the human body dramatically impacts the effectiveness of that antenna. In other words, if the form factor and design of the physical product are decided independently of your wireless design, you may have painted your RF/Antenna designer into a corner and the only way out is a complete re-design.

“The key for

success in designing

Wearable Tech is

to approach both

the Industrial

and Wireless

Technology Design

methodologies

holistically.”

WHAT’S AT RISK IF INDUSTRIAL DESIGN AND WIRELESS DESIGN ARE NOT ADDRESSED COLLECTIVELY?

• Multiple design and prototype iterations• Product development deadlines broken and budgets overrun• A product that your customers simply don’t want

2222

REAL WORLD EXAMPLE: MEMI PRODUCT DEVELOPMENT PROGRAM AT LSR

Most companies gaining traction in the Wearable Tech space are doing so by focusing on specific problems, deeply understanding the needs and preferences of their target customer, and by being careful not to overload the individual with extra features that could

complicate and dilute the real value of the product. LSR has had the

exciting opportunity to partner with the dynamic team at MEMI (www.hellomemi.com) to bring an innovative wearable product concept

to reality. MEMI is creating a solution that helps women

be connected without looking connected. Their fashionable, jewelry-

like bracelet device stays wirelessly connected to a smartphone in order to alert the user through vibration when she receives a text or call from an important contact.

Due to the MEMI’s proximity to the body and the materials used, both the industrial design of the piece and the design of the antenna were looked at collectively by the team to ensure a winning design. The combination of collaboration and expertise here at LSR has enabled the development of MEMI to move forward quickly and clearly.

For this project, the requirement that the design incorporates metal in order to be jewelry-like in appearance strongly impacted the antenna design. Early on in the development process, the Industrial Designers and Antenna Designers sat down to collaborate on potential viable options. The team developed multiple concepts using different antenna topologies. The one that rose to the top was the “external antenna”. With this design, two of the outer metal bracelet parts actually function as part of the antenna, and design changes to minimize the metal on the inside of the bracelet further improved the antenna performance. If the team had not worked collaboratively to find an optimal solution, there may have been unnecessary sacrifices made in the aesthetics or the antenna performance, or both. In the end, MEMI had a product they feel will hit the mark with their customers because the team ensured the “hammock” was tied securely on both ends! A Wearable Tech product that truly exceeds your customer’s expectations not only requires a strong form factor, but at its core it is a product that must perform its function well. So as you set out to develop such a product, you will discover there are a lot of technical challenges to solve in doing so, as well. So if your organization is looking to embark on capitalizing on the Wearable Tech trend, it is critical to ask and answer the following question: “Do we have strong technical competence under our roof in both Industrial Design and Antenna/RF Design to ensure a collaborative product development

approach?” If not, the recipe for success likely will lead you partnering with specialists who can deliver that approach.

Hopefully, this example of an integrated design process where Industrial and Wireless Design were approached holistically has given you some food for thought. Although the product development of a wearable product can be deceptively complex, we encourage you to be courageous in creating your solutions and taking advantage of the many benefits wearable wireless products can deliver if done well. The following list of Do’s and Don’ts may be helpful in your efforts.

IN ADDITION TO HAVING THE RIGHT EXPERTISE IN YOUR ORGANIZATION, YOU MUST ALSO ASSESS THE TOOLS AND EQUIPMENT, INCLUDING:

• 3D CAD, Modeling and Rendering software (such as SolidWorks)

• 3D Antenna design software (such as CST Microwave Studio)• An Anechoic Chamber and Network Analyzer for antenna testing & certification

DO’s: DON’Ts

Use an integrated team with expertise in both wearables and antenna design.

Don’t be everything to everybody. Know your end user and stay focused on the key value your solution offers.

Have a plan for the antenna as soon as possible. Explore more than one option, as first ideas are not always the best. Remember, the performance of the antenna is directly related to other design decisions in the product, such as materials used.

Don’t just copy what others have done. There may be better solutions, and will go a long way in creating differentiation in the marketplace by offering a unique design.

Prototype and test often and as accurately as possible, to ensure best possible technical performance.Remeber the body is soft and curvy, and location and poximity to the body can make huge performance differences. Ex- plore flexible PCBs, formable antennas, and sewn goods if appropriate.

Don’t keep your Industrial designers isolated from the RF/antenna designers. If so, there will be missed opportunities, budgets spent and corners to design yourself out of.

Wearable Tech Product Design | DO’s & DONT’s

Want to learn more about successful product development approaches for Wearable Tech?

LSR is a global leader in enabling

advanced wireless technology

platforms including Wi-Fi®,

Bluetooth®, BLE, Cellular, RFID,

NFC, 802.15.4, DECT, and ZigBee®.

LSR is the only wireless product

development company providing

turnkey M2M System Solutions

with Design Services, on- site FCC

/ IC / CE Testing and Certification

and a broad line of RF modules.

Learn more at www.lsr.com.

23

TECH ARTICLE

23

REAL WORLD EXAMPLE: MEMI PRODUCT DEVELOPMENT PROGRAM AT LSR

Most companies gaining traction in the Wearable Tech space are doing so by focusing on specific problems, deeply understanding the needs and preferences of their target customer, and by being careful not to overload the individual with extra features that could

complicate and dilute the real value of the product. LSR has had the

exciting opportunity to partner with the dynamic team at MEMI (www.hellomemi.com) to bring an innovative wearable product concept

to reality. MEMI is creating a solution that helps women

be connected without looking connected. Their fashionable, jewelry-

like bracelet device stays wirelessly connected to a smartphone in order to alert the user through vibration when she receives a text or call from an important contact.

Due to the MEMI’s proximity to the body and the materials used, both the industrial design of the piece and the design of the antenna were looked at collectively by the team to ensure a winning design. The combination of collaboration and expertise here at LSR has enabled the development of MEMI to move forward quickly and clearly.

For this project, the requirement that the design incorporates metal in order to be jewelry-like in appearance strongly impacted the antenna design. Early on in the development process, the Industrial Designers and Antenna Designers sat down to collaborate on potential viable options. The team developed multiple concepts using different antenna topologies. The one that rose to the top was the “external antenna”. With this design, two of the outer metal bracelet parts actually function as part of the antenna, and design changes to minimize the metal on the inside of the bracelet further improved the antenna performance. If the team had not worked collaboratively to find an optimal solution, there may have been unnecessary sacrifices made in the aesthetics or the antenna performance, or both. In the end, MEMI had a product they feel will hit the mark with their customers because the team ensured the “hammock” was tied securely on both ends! A Wearable Tech product that truly exceeds your customer’s expectations not only requires a strong form factor, but at its core it is a product that must perform its function well. So as you set out to develop such a product, you will discover there are a lot of technical challenges to solve in doing so, as well. So if your organization is looking to embark on capitalizing on the Wearable Tech trend, it is critical to ask and answer the following question: “Do we have strong technical competence under our roof in both Industrial Design and Antenna/RF Design to ensure a collaborative product development

approach?” If not, the recipe for success likely will lead you partnering with specialists who can deliver that approach.

Hopefully, this example of an integrated design process where Industrial and Wireless Design were approached holistically has given you some food for thought. Although the product development of a wearable product can be deceptively complex, we encourage you to be courageous in creating your solutions and taking advantage of the many benefits wearable wireless products can deliver if done well. The following list of Do’s and Don’ts may be helpful in your efforts.

IN ADDITION TO HAVING THE RIGHT EXPERTISE IN YOUR ORGANIZATION, YOU MUST ALSO ASSESS THE TOOLS AND EQUIPMENT, INCLUDING:

• 3D CAD, Modeling and Rendering software (such as SolidWorks)

• 3D Antenna design software (such as CST Microwave Studio)• An Anechoic Chamber and Network Analyzer for antenna testing & certification

DO’s: DON’Ts

Use an integrated team with expertise in both wearables and antenna design.

Don’t be everything to everybody. Know your end user and stay focused on the key value your solution offers.

Have a plan for the antenna as soon as possible. Explore more than one option, as first ideas are not always the best. Remember, the performance of the antenna is directly related to other design decisions in the product, such as materials used.

Don’t just copy what others have done. There may be better solutions, and will go a long way in creating differentiation in the marketplace by offering a unique design.

Prototype and test often and as accurately as possible, to ensure best possible technical performance.Remeber the body is soft and curvy, and location and poximity to the body can make huge performance differences. Ex- plore flexible PCBs, formable antennas, and sewn goods if appropriate.

Don’t keep your Industrial designers isolated from the RF/antenna designers. If so, there will be missed opportunities, budgets spent and corners to design yourself out of.

Wearable Tech Product Design | DO’s & DONT’s

Want to learn more about successful product development approaches for Wearable Tech?

LSR is a global leader in enabling

advanced wireless technology

platforms including Wi-Fi®,

Bluetooth®, BLE, Cellular, RFID,

NFC, 802.15.4, DECT, and ZigBee®.

LSR is the only wireless product

development company providing

turnkey M2M System Solutions

with Design Services, on- site FCC

/ IC / CE Testing and Certification

and a broad line of RF modules.

Learn more at www.lsr.com.

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