Implementation Challenges of UWB Systems

Transcription

1 Implementation Challenges of UWB Systems Vancouver, British Columbia March 10, 2006 By: Alon Newton

2 If things were so easy

3 A 2 cents UWB antenna(1)

4 UWB in a nutshell New type of radio uses an already existing devices (which may not be even RF devices) Heinrich Rudolf Hertz was the first to broadcast and receive radio waves between 1885 and In essence, the first radio ever was an UWB device... (2)

5 Hertz experiments

6 Why do we call it Ultra Wide Band? Jean Baptiste Joseph Fourier (3) Any non repetitive signal can be represented as a combination of repetitive signals In other words a transfer from the time domain to the frequency domain translates short pulses into frequency rich spectrum

7 Half the truth Based on the FCC definition of minimum 500MHz there is another option MBOA MultiBand OFDM can fit a similar spectral mask but based on narrow band techniques Seen as an extension to Bluethooth Popular approach with a lot of industry support

8 So simple? Where can we buy it? In USA (4). UWB is still illegal in most of the world including Canada A lot of effort is being made to fully utilize the available capacity of UWB but it not simple or affordable as of yet. IEEE standardizing for high data rate recently abandoned The low data rate and low power standard is still being worked on (IEEE TGa) (5)

9 UWB emission mask

10 UWB FCC mask & UNII mask

11 Ideal UWB TX mask

12 Actual complex pulse and its FFT A nice interactive demo can be found on line (4)

13 UWB background summary (UWB systems use PULSES not sinusoidal waves) Uses wide bandwidth (short pulses in time domain) Less sensitive to multi-path fading (time gated) Appears as noise (hidden from interception and jamming; minor interference with other users) Larger bandwidth allows more total power to be transmitted (more energy per bit) UWB radars can use non-coherent methods to resolve the distance a pulse has traveled to within centimeters (micro impulse radar) Potential low cost implementation CMOS based transceiver is possible Signal Time area under curve (power) larger due to increased bandwidth Frequency Noise

14 Niche UWB applications Utilizing low data rate, low power and short to medium range UWB signals Operating within the current FCC limits UWB enables better penetration through materials and can be used as a Doppler radar to detect motion even behind walls (6) Wireless 2000 is currently developing: UWB based heart rate and respiration rate monitor UWB based location system

15 UWB based heart rate monitor Non invasive, non contact Provides information about the mechanical movement, not the electrical stimulation (7)

16 HRRM prototype board

17 Radar Cross Section

18 How to start a UWB project? One may need to: Investigate existing UWB patents Investigate current and potential markets Identify the unique design tools such as simulation, CAD & test equipment Locate experienced manpower for the job Practical examples: Most of the early patents invented by Tom McEwan at LLNL belong to the US government The only viable market as of today is the US (under FCC) Most frequency domain simulation tools have very limited time capability Most candidates we met have simulated UWB but never built one

19 Simulation tools General tools can be used to design communication protocols, capacity Classic TD tools such as SPICE usually fail to accurately simulate nanosecond pulses Classic FD tools are helpful only for the discrete elements design (Group Delay) Designs tool box or design guides are usually too specific in most cases Simulation can easily yield unrealistic results

20 Test & assembly equipment (general) Sampling and general purpose oscilloscopes Network analyzer (up to 10.6GHz) Spectrum analyzer (up to 40GHz) Signal and pulse generator Calibrated antenna (for pre screening) Anechoic chamber Microscope & SMT hand tools Component design kits PCB layout CAD

21 Specific parameters and issues UWB pulses are measured in nanoseconds. What is the resolution of the test equipment? Most wide band antennas are actually multi band and do not have a constant group delay or linear phase Harmonics must be tested up to 40GHz for compliance Synchronization and repetitive transmission for signal capture (triggering issues) Most certified laboratories lake experience with UWB Experimental license is usually required

22 Experimental license (useless BW)

23 Examples - sampler (8)

24 Examples - sampling

25 Examples - strobe

26 Examples TD TEM antenna (9)

27 Examples Large Current Radiator

28 Examples - Vivaldi

29 Examples - Bowtie

30 Examples - PICA

31 How are we doing so far?

32 Example UWB radar

33 Example UWB radar TX

34 Example UWB radar RX

35 Communication system

36 UWB propagation indoors

37 UWB propagation model

38 Existing UWB based products

39 Existing UWB based products

40 Existing UWB based products

41 Existing UWB based products

42 Existing UWB based products

43 Existing UWB based products (10)

44 Existing UWB based products (11)

45 Existing UWB based products (12) Ubisense Hybrid UHF UWB asset location tracking system

46 Existing UWB based products (13)

47 Other interesting UWB projects To learn more about the IGERT SKINS program, visit Erick Maxwell s homepage is: Unclassified and Commercial Technology Capable of Some Electronic Harassment Effects

48 Links (1) (2) (3) (4) (5) (6) (7) (8) mley_sampcircmodel_com.pdf (9) (10) R_Overview.pdf (11)

49 Links (continued) (12) uary% pdf (13)

50 Notes summary 1 *Alon Newton, Engineering Manager* In 2003, Alon joined Wireless 2000 as their Engineering Manager bringing with him over 15 years of experience in the RF/ Microwave, Electro Optics and consumer electronics communications manufacturing industries. Prior to taking on the role of Engineering Manager within Wireless 2000, Alon took on roles within increasing responsibility. Starting out as an RF/Microwave Engineer, he soon took on the roles of Senior RF Engineer, Senior RF Design Engineer, with his last role being a Senior Development Engineer at Scientific Atlanta Canada. Alon is a registered Professional Engineer in British Columbia and earned his Bachelor of Science degree in Electrical Engineering at the Technion, Haifa, Israel. _ *Wireless 2000 RF & UWB Technologies *is an Engineering and R&D company based on qualified professionals with advanced academic degrees and extensive practical experience in RF, RFID, UWB and wireless communications technology. We provide customer contract designs, product development and R&D services. Currently we have 10 Electrical Engineers and one Mechanical Engineer as well as contractors and periodically CO-OP students. We are members of WinBC and participated in few Industry Canada trade missions. Wireless 2000 is privately funded and wholly Canadian owned corporation.