7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

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YRS-UCLA-07

From Maxwells Equations to Modern

Communication Antenna Marvels:An Amazing Journey of Novel Designs

Yahya Rahmat-SamiiProfessor & Past Chairman

Electrical Engineering Department

U of California Los Angeles (UCLA)U.S.A.

email: rahmat@ee.ucla.edu

http://www.ee.ucla.edu/antlab

7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

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Potential Approaches for

Miniaturization

High Dielectric ConstantDouble Negative Material

Low Profile using EBG

Folding Antenna StructureStructure Profiling, Fractal, etc.

Incorporation of Switches

Hybridizations of AboveStored Energy Utilization

Many aspects of these will be also touched

upon in this talk. YRS-UCLA-07

7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

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7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

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1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3-25

-20

-15

-10

-5

0

Frequency (GHz)

ReturnLoss(d

B)

Wide Band DesignDual-frequency Design

Antenna

II

Antenna

I100 200 300 400 500 600 700 800 900 100038

40

42

44

46

48

50

The Nth Iteration

FitnessValue

Average fitness at the current iterationg

bestup to the current iteration

PSO/FDTD in Broadband Patch Antenna Design:

Parameter Approach

Ls

w

xf

Ps

ws

L

L/2 31% bandwidth

Measurement ResultsConvergence

E-Shape

Antenna

YRS-UCLA-07

7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

5/18

Keyboard Influence Investigation

Measurement Results

No keyboard 900 1200

YRS-UCLA-07

7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

6/18

MIMO Arrays Design and System Testing

UCLA True MIMO Testbed(David Brown and Michael Fitz)

Testing of designed

antennas in real system

environment

Evaluation of system

capacity as a function of

antenna characteristics and

array topology

Directional Omnidirectional Array Configurations

YRS-UCLA-07

7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

7/18

UCLA Miniature MIMO Arrays

YRS-UCLA-07

7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

8/18

Tri-Band PIFA

2 3 4 5 6 7-30

-25

-20

-15

-10

-5

0

f (GHz)

R

eflectioncoefficient(dB

)

MeasuredCalculated

Tri-band PIFA using J-shaped

and quarter wavelength slots.

Calculated and measured reflection

coefficient of the tri-band PIFA.

Adding a quarter wavelength slot generates the third resonant frequency.

Although, the small PIFA couples with the quarter wavelength slot, these

two higher frequency bands can be brought as closely as desired.

PIFA 2PIFA 1

Slot

2.45GHz

5.25GHz

5.75GHz

YRS-UCLA-07

7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

9/18

UCLA

Fractal Antennas and MIMOSelf-similaritySpace filling ability

Properties of Fractal Antennas that

potentially benefit antenna design:

Space filling property to miniaturize

wire and patch antennas

Self-similarity to design multiband

antennas

MIMO

Packaging 4 fractal

elements in the same

space as 3 standardsYRS-UCLA-07

7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

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Reconfigurable Antennas: Patch Antennas

Ground Plane

Patch

SlotSwitch

LHCP/RHCP diversity

Dual band CP performance

(2)

(1)

Dual frequency operationYRS-UCLA-07

7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

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Switch - off Switch - on

Operational Mechanism: Current Flow

Switch-off, LHCPx is /2 ahead

Switch-on, RHCP-y is /2 ahead

Feed Point

x

y

z

Reconfigurable Dual-Frequency Dual-CP Antenna for Wireless Communications

3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

0

Frequency (GHz)

ReturnLoss(dB)

Switch off, Mesurement

Switch off, Simulation

Switch on, Mesurement

Switch on, Simulation

Simulation

Measurement

3.6 3.8 4 4.2 4.4 4.6 4.8 5 5.2 5.4-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

0

Frequency (GHz)

ReturnLoss(dB)

Switch off, Mesurement

Switch off, Simulation

Switch on, Mesurement

Switch on, Simulation

Simulation

Measurement

-30dB-20dB

-10dB 0dB

30

210

60

240

90270

120

300

150

330

180

= =

f=4.38GHz, LHCP, =0

-30dB-20dB -10dB

0dB

30

210

60

240

90270

120

300

150

330

180

0

f=4.38GHz,LHCP,=90(deg)

f=4.38GHz, LHCP, =90

MEMS switches can be used for

low loss operations.

YRS-UCLA-07

7/27/2019 From Maxwells Equations to Modern Communication Antenna Marvels: An Amazing Journey of Novel Designs By Yahya Rahmat-Samii Professor & Past Chairman Electrical Eng

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YRS-UCLA-07

Meta-Materials( Beyond the nature; none existing in the nature)

Artificial complexground planes

Double NegativeMaterials (Left-handed)

0

0