45 nm transistor
45nm = .045um (microns)= 450 Angstroms
Review Safety Test
Wireless Technology
• Wireless devices transmit information via Electromagnetic waves
• Early wireless devices– Radios – often called wireless in old WWII
movies– Broadcast TV– TV remote controls– Garage door openers
Wireless technology
• Today’s wireless devices include– Mobile phones– Satellite TV– Satellite radio– Global Positioning Systems (GPS)– “Bluetooth” devices– Wi-Fi systems– RFID tags
Apple iPhone
Mobile Phone (Cellular) Systems
• Mobile phones are two-way radios. They transmit and receive RF signals. Old style phones are not radios.
• Original mobile phones used a single large central antenna and had limited channels available to carry signals. Only a small number of mobile phones were available in a city due to the limited amount of usable frequency bands.
• Cellular technology allowed for a near limitless number of mobile phones to operate in a city.
Mobile Phone (Cellular) Systems
• Cellular systems operate at a frequency of 824 to 894 Mhz, and 1850 to 1990 Mhz . Other bands are also being used as demand increases.
• These frequency bands are controlled by the Federal government.• The original cell phones operated at 824-894 MHz. Sometimes
these phones are referred to as “analog phones” since digital technology had not yet been developed.
• Systems today operate mostly at 1850 to 1990 Mhz, the PCS band in the digital mode but can also operate at the lower frequency band. These phones are called “dual band” phones.
• The term “cellular” refers to the fact that service areas are divided into “cells” typically 1- 10 miles apart. Cell size is dependent on the population density of the area. Large population areas require closer spaced cells.
• Each cellular company has their own towers, thus the large number of towers throughout the area. Sometimes towers will have multiple sets for the same system or multiple systems.
PCS Band1850-1990
MHZ
Grid pattern for cellular antenna
Adjacent grids do not use the same frequency
Mobile Phone (Cellular) Systems
• Each phone has a unique code.• If your cell phone is “on”, it is transmitting a signal to the
nearest cell tower.• This signal locates you and allows you to receive calls.• It also identifies your phone, carrier, and status of your
account.• When you make a call, it is transmitted to the nearest
tower and it is then routed to the person you called.• The call may go via radio waves, land lines, or satellite.• As you move, the call can be transferred to the next cell.
This is done automatically as signal strength changes• Phones typically transmit with around 600mW of power.
Typical cellular system antenna tower
Base station RF transmit/receive
modules
Communities are trying to disguise cellular towers
“ Bluetooth”
• “Bluetooth” named after a Swedish King that united the country. First proposed by Ericsson
• The systems utilizes an unregulated band of frequencies at 2.4 GHz that operate on a relatively short distance, about 10m.
• Bluetooth uses a “frequency hop transceiver” to handle device traffic. A radio channel is shared by a group of devices and is synchronized by one device known as the master. This forms a piconet.
• Bluetooth devices can be used to connect a headset to a cellular phone, a printer to a computer, a digital camera to a computer, etc.
• Because “Bluetooth” circuits are low power with low battery requirements, the chipsets are relatively inexpensive.
• Many newer devices have “Bluetooth” already built into them.
Wi-Fi –provides access to internet wirelessly
• Uses IEEE standard 802.11• Transmits at
– 2.4 GHz (802.11b and 802.11g)– 5.0 GHz (802.11a)
• Transfer Rates– 802.11a and 802.11g (54 Megabits per second)– 802.11b (11 Mega bits per second)
• Frequency hopping for security• Range: about 100 meters (300 feet)• Range limited by output power level.
“Bluetooth” vs. Wi-Fi
• Both use the 2.4 GHz frequency band
• Both could use the same antenna
• “Bluetooth” is for short range, about 10m
• Wi-Fi has a longer range, about 100m
• “Bluetooth” can operate from a small battery
• Wi-Fi requires higher power, usually plugs into a home electrical outlet
RFID tags
• Passive -uses the incoming signal for power to transmit
• Active- requires an internal power supply, more expensive and less widely used
• Could replace bar codes and security attachments on merchandise
• Implantable for medical and security data
Implantable RFID device
Antenna Design
• In antenna design, an important design parameter is the wavelength of the EM wave
• Wavelength is a function of frequency
• Antenna length is typically either 1. 1 wavelength
2. ¼ wavelength
3. ½ wavelength
Frequency vs wavelength
Wavelength
Wavelength Calculations
• Wavelength units:(wavelength) m/cyclef (frequency) cycles/sec = hertzc (speed of light) m/sec3.0 x 108
m/sec
• Wavelength equationc / fm/cycle = (m/sec) / (cycles/sec)
Sample calculation• Find the wavelength of a frequency of 850 MHz
1. Convert 850 MHz to Hz850 MHz = 850 x 106 Hz = 8.50 x 108 Hz
2. Use wavelength equation= c/f where c = speed of light = 3.0 x 108 m/sec
3. 3.x 108 m/sec ) / (8.50 x 108 cycles/sec)
4. = .353 m/cycleConvert to cm gives
5. = 35.3 cm/cycle6. For a ¼ wavelength antenna =
(35.3cm/cycle)/4=8.825cm/cycle
Assignment due next class
• HW #5 from the web site– Frequency and wavelength calculation
• Begin discussions with your team on what application to pursue for your project
