Millimeter and Tera-Hertz waves applications for communications and homeland security

Transcription

1 ה מרכז האוני ברסיטאי אריאל Ariel University Center of Samaria בשומרון ה מ חל ק ה ל הנ דס ת ח ש מל ו אל קט רונ יק ה Dept. of Electrical and Electronic Engineering Millimeter and Tera-Hertz waves applications for communications and homeland security Prof. Yosef Pinhasi

2 BAND Extremely Low Frequency Super Low Frequency Ultra Low Frequency Very Low Frequency Low Frequency Medium Frequency High Frequency Very High Frequency Ultra High Frequency Super High Frequency Extremely High Frequency Sub-millimeter (TeraHertz) Mid infra-red Near infra-red ELF SLF ULF VLF LF MF HF VHF UHF SHF EHF FIR MIR NIR IEEE L S C X Ku K Ka V W D FREQUENCY 3-30Hz Hz 300-3,000 Hz 3-30 KHz KHz 300-3,000 KHz 3-30 MHz MHz 300-3,000 MHz 1 - GHz - 4 GHz 3-30 GHz 4-8 GHz 8-1 GHz 1-18 GHz GHz GHz GHz GHz GHz GHz 300-3,000 GHz 3 30 THz THz WAVELENGTH 1, Km Km 10-1 Km Km m 10 1 m m 10-1 cm cm mm μm 10 1 μm

3 Propagation in dielectric media

4 Complex dielectric constant ~ D ~ ~ ( f ) = ε E( f ) + P( f ) = ε( f ) E( f ) = ε [ ε '( f ) jε'' ( f )] ~ ε r ( f ) ~ E ( f ) ε r ( f ) = ε' ( f ) jε' '( f ) ε '' ( f ) = σ πf ε 0 tg [ δ ( f )] = ε '' ε ' ( f ) σ = ( f ) πf ε '( f ) 0 ε

5 ~ Ε out Complex propagation coefficient ~ [ ] d ( ) ( ) jk( f ) d ( ) ( f ) j ( f ) f = Ε f e = Ε f e α + β in πf k = r β c ( f ) ε ( f ) = jα( f ) + ( f ) ~ in α β ( f ) ( f ) = = πf c πf c ε ' ε ' ( f ) ( f ) { [ ( ) } 1+ tg δ f ] 1 { [ ( ) } 1+ tg δ f ] + 1

6

7 Space-frequency model TRANSMITTER RECEIVER I in (t) MEDIUM I out (t) cos(ω c t) H ( jf ) cos(ω c t) Q in (t) Q out (t) -sin(ω c t) -sin(ω c t)

8 Transmission of modulated signal A E in in () t = I ( t) jq ( t) in { ( ) j f t } A t e π c ( t) = Re in in E out { ( ) j f t } A t e π c ( t) = Re out A = out + () t = I ( t) jq ( t) A in out out ( f ) H ( f + f ) c e = + jπft df

9 0log( e) α ( ) [ db ] f Km Δβ ( ) [ rad ] f Km

10 LINK BUDGET P r P t = c G G t r 4π f d e α( f )d FRIIS T. H. Friis: A note on a simple transmission formula, Proc. IRE 34, (1946), 54-56

11 COMMUNICATION RANGE - HORIZONTAL Transmitted power: Bit rate: Receiver noise figure: Eb/No: 10dBm 1MBPS 10dB 10dB FREQUENCY ATTENUATION ANTENNA DISTANCE 35GHz -0.1 db/km 0dBi 100 m 60GHz -15 db/km 0dBi 60 m 94GHz -0.3 db/km 0dBi 40 m 119GHz - db/km 0dBi 30 m

12 Unlicensed 60GHz band (EHF)

13

14 60GHz Wireless Personal Area Network IEEE c 11,, 33, 44, & 55 MBPS Ad hoc peer-to-peer networking Designed to meet the demanding requirements of portable consumer imaging and multimedia applications The mm Wave WPAN will operate in the GHz unlicensed band defined by FCC 47 CFR The millimeter-wave WPAN will allow high coexistence (close physical spacing) with all other microwave systems in the family of WPANs.

15 GAUSSIAN PULSE A in () t = e t σ in

16 ANALYTICAL RESULTS () ( ) ( ) ( ) 0 '' ' 1 exp out t d t in in out e d d d t A σ + α πσ α + α σ σ ( ) d d d t in d α + πσ β α β π = ' ' ' ' ' ' 1 ( ) ( ) ( ) ' ' ' ' ' ' π α + σ π β + π α + σ = σ d d d in in out

17 00 ps pulse

18 Remote sensing and imaging in sub-millimeter and Tera-Hertz Waves

19 Transmission of clothes

20 THz Gap Millimeter and Sub-Millimeter Waves

21 Millimeter and Tera-Hertz Spatial resolution. characteristics Small equipment and antennas. Quasi optical, near field. Non-metallic, non-polar materials are transparent. Target compounds have characteristic THz spectra that can be used to identify these compounds. THz radiation poses no health risk for scanning of people. Metals completely block or reflect THz waves. Ceramic guns and knives would partially reflect the THz waves.

22 Passive imaging at millimeter wavelengths

23 Example THz imaging Azimuth/elevation collection of a clothed mannequin with a concealed, metal tiewrap gun (inset). Left image taken at 1.56THz. Center image taken at 350GHz (dbv color scale). Photograph of subject as measured on right. Note the penetration through the black plastic wrapping of the trigger handle at 350GHz. The black plastic wrap is heavily attenuating at 1.56THz and minimally attenuating at 350GHz, allowing the handle metal to reflect brightly.

24 DETECTION AND IDENTIFICATION OF EXPLOSIVES

25 Absorption and reflection of explosives (TeraView) Semtex

26 Spectral lines of explosives and drugs

27 Radiation sources

28 Backward Wave Oscillators

29

30 Pyroelectric detector

31 Experimental setup

32 Characterization of Explosives

33 Dummy explosives Deta Semtex ε ' Deta Semtex TNT Deta Semtex TNT TNT ε '' Frequency, THz

34 Clothes Absorption, db f, THz Absorption Coefficient, cm -1 (1/e) f, THz

35 Active imaging

36 Active imaging - THz Radar system

37 Linear FM (FMCW) Radar Δf peak VCO Y linear-fm (t) f m 0 τ T T+τ Z(t) LPF Product Detector Y linear-fm (t-τ) Δf peak ylinear FM () t = Ac cos πf ct + π t T Δf peak ylinear FM ( t τ ) = Acos πf c( t τ ) + π ( t τ ) + θ T A A Δf Δf c peak peak z() t = cos π τ t + πf cτ π τ θ 1443 T T ν IF d = 30m Δf peak d Δf peak = 500MHz, T = 100mS ν IF = =1, 000Hz T c

38 340GHz FMCW RADAR system Transmitter Power Box Control/Bias Box Amplifier Multiplier Chain RF input ELTA Syn. ( GHz) X4 X X X RFOutput (30-330GHz) Plate Connect RF Output Power ON/OFF Control/Bias Box Power Input RF Input TTL Modulation User Controlled Attenuation Plate connector; to Mix. Chain

39 340GHz FMCW RADAR system Receiver Power Box Amplified Mixer Chain IFOutput LO input Synthesizer ( GHz) X16 Isolator X Mixer RFInput (30-330GHz) IF Output Plate Connector Screws; to Multiplier Chain System ON/OFF RF Input LO Input

40 Imaging Thru Walls - MM-Wave Brick wall Screen T-rays source

41 Propagation through walls