1. Engr 1202 E01 Clean Room Project

2. Dilbert the engineer gets special recognition

5. September 2005

6. 2014 Version – does not even have my name!

7. AC vs. DC Circuits

8. DC and AC devices in everyday life DC Devices –Batteries –Automotive electronics –Portable electronics IPod Cellular Phone PDA –Laptop computers –Desktop computers –Solar cells –Computer and memory chips AC Devices –Electric wall outlets –Household appliances –High voltage transmission lines –Electromagnetic transmissions Mobile phone signals Satellite signals Radio signals

9. AC Frequency Number of complete cycles per unit time Units are hertz, Hz Units are cycles per second Household electrical outlets operate at 60 hertz or 60 cycles per second Electromagnetic waves operate at much higher frequencies

10. Sun burn

11. Frequency Allocations

12. Broadcast Frequencies Use of frequencies for broadcast are controlled by the Federal Government – the FCC - Federal Communications Commission License required to use a given frequency Companies purchase licenses to use these frequencies Specific bands are setup for all transmissions –Police/Fire/EMS radio –Commercial aircraft –Marine radios –Mobile phones –Military applications –Citizen band radio –GPS –RFID Bluetooth and Wi-Fi operate in the scientific unlicensed band where products can be developed without a FCC license

13. Typical large broadcast antenna Very tall, often on mountains, to transmit over long distances

14. Some common frequencies AM Radio –535 to 1605 KHz FM Radio –88-108 MHz Broadcast TV (old)- requires external antenna –Channels 2-4 54-72 MHz –Channels 5-6 76-88 MHz –Channels 7-13 174-216 MHz –Channels 14-36 470-608 MHz –Channels 38-69 614-806 MHz Today, most TV transmissions are digitized and sent via cable, fiber optics, or satellite

15. 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

16. Wireless technology Today’s wireless devices include –Mobile phones –Satellite TV –Satellite radio –Global Positioning Systems (GPS) –“Bluetooth” devices –Wi-Fi systems –RFID tags

17. Wireless frequencies for the EE project PCS digital phones - 1850-1990 MHz – Current frequency of operation of most mobile phones Bluetooth and Wi-Fi devices - 2400-2497 MHz (2.4 – 2.497 GHz) GPS – 1575.42 and 1227.60 MHz RFID – multiple frequencies – 860 to 960 MHz very common

18. Smart phones dominate cellular systems today

19. Apple iPhone A computer that is also a cell phone

20. 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.

21. Early Mobile Phones where not cellular but used a common centrally located tall antenna (similar to police and fire radios) and were limited in the number of phone numbers available

22. 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. Many systems today operate 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.

23. My first cell phone - 1992

24. PCS Band 1850-1990 MHZ

25. Grid pattern for cellular antenna Adjacent grids do not use the same frequency

26. 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.

27. Typical cellular system antenna tower with two sets of base station modules Base station RF transmit/receive modules

28. Large cell phone antenna is a remote location

29. Communities are trying to disguise cellular towers Several cell phone antenna towers like this are near the campus

30. First cell phone tower on campus

31. “ 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.

33. 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. Often called a “Hotspot”

34. Installing a home Wi-Fi network is easy and cheap

35. A city wide Wi-Fi zone can be created using multiple routers similar to the cell phone antenna network

36. “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

37. Smart phones can access the internet either through a local Wi-Fi access point or the cellphone network

38. Instead of using a Wi-Fi location, you can access the internet through the cellular phone network BUT you will pay for the time. Could be expensive unless you have unlimited data downloads Allows for your laptop to access the internet via the cellular system

39. 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

40. Implantable RFID device

41. Companies like Wal-Mart plan to use RFID extensively

42. RFID gate access at UNCC

43. GPS systems uses orbiting satellites The primary frequency of operation is 1575.42 MHz with a secondary frequency of 1227.6 MHz Cellular GPS systems use local cellular antennas

44. Stationary Satellites Orbit the Earth

45. GPS devices calculate the signal time from each satellite and using triangulation determine location

46. Communications – the key to technology progress Data, voice, and video are all key elements Both electrical and computer engineers will play a key and vital role “Wireless” communications is the dominate form The EE project will focus on communications systems and a key element of these system, the antenna.

47. What is an antenna The antenna is an essential part of any wireless communication system that sends information over the air. An antenna is a device that provides a means for radiating or receiving electromagnetic waves. It provides a transition from a guided wave on a transmission line to a free space wave or vice versa.

48. Every communications device needs an antenna

50. The Engr 1202 EE Project Research, design, and fabricate a miniature planar antenna for use in: 1)Mobile phone using the PCS frequency of 1850-1990 MHz 2)“Bluetooth” and Wi-Fi antenna using the frequency band of 2400-2597 MHz 3)RFID antenna using the frequency band of 860-960 MHz 4)GPS antenna using the frequencies of 1227.60 MHz and 1575.42 MHz Maximum size of 20mm x 20mm, minimum size of 10mm x 10mm. Can be rectangular. Width on antenna not less than 1mm. Design to have no sharp corners.

51. Cell phone showing internal antenna Antenna

52. Example of a miniature antenna for a mobile phone/watch

53. 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

54. Frequency vs wavelength Wavelength

55. Wavelength Calculations Wavelength units:  (wavelength) m/cycle f (frequency) cycles/sec = hertz c (speed of light) m/sec  3.0 x 10 8 m/sec Wavelength equation  c / f m/cycle = (m/sec) / (cycles/sec) Frequency must be converted to Hz

56. Sample calculation Find the wavelength of a frequency of 850 MHz 1.Convert 850 MHz to Hz 850 MHz = 850 x 10 6 Hz = 8.50 x 10 8 Hz 2.Use wavelength equation = c/f where c = speed of light = 3.0 x 10 8 m/sec  x 10 8 m/sec ) / (8.50 x 10 8 cycles/sec)  =.353 m/cycle Convert to cm gives  = 35.3 cm/cycle 6.For a ¼ wavelength antenna = (35.3cm/cycle)/4=8.825cm/cycle

57. To find wavelength 1.Convert frequency to Hz (cycles/sec) 2.Use 3.0 x 10 8 m/sec for speed of radio waves (same as speed of light) 3.Use equation wavelength (m/cycle) = speed of light (m/sec) / frequency (cycles/sec) Wavelength is use to determine antenna length

58. Antenna Design Design can take an artistic form (not the best design for an antenna but OK for this project) Design must not be controversial –Not religious –Not gang sign –Not sexual –Not offensive to any group

59. Example of antenna design Dimension DrawingDesign arrayed for 4” wafer

60. Assignment due next class HW #2 from the web site –Frequency and wavelength work sheet Sketch your antenna design to be ready to transfer into AutoCAD A final report on the project is due at completion. –PowerPoint format –One per team –Summary of project including photos in the clean room