Presentation is loading. Please wait.

Presentation is loading. Please wait.

Classical Electrodynamics Applied in Modern Technology Günter Nimtz Physics Department, University of Cologne 1. Properties of Nano-Metal Films 2. Anechoic.

Similar presentations


Presentation on theme: "Classical Electrodynamics Applied in Modern Technology Günter Nimtz Physics Department, University of Cologne 1. Properties of Nano-Metal Films 2. Anechoic."— Presentation transcript:

1 Classical Electrodynamics Applied in Modern Technology Günter Nimtz Physics Department, University of Cologne 1. Properties of Nano-Metal Films 2. Anechoic EMC Chambers: Pyramidal Absorber 3.Absorption by Anechoic Traps: Reflecting Curtains 4. Ferrite Tile Absorber……….Hybrid Absorbers 5.Rain Sensing Wipers: Frustrated Total Internal Reflection = Tunneling

2 Free carrier EM interaction : Drude (1900), Hagen & Rubens (1902) Nano metal films ( gravimetrical determination ! ) Infrared studies on Absorption, Reflection and Transmission: A + R + T = 1 Murmann; Barnes; Czerny; Woltersdorff (1929 – 1934)

3 R + T + A = 1 of Nano-Film Resistance Angle of incidence = TM = 45 0 EM = 45 0 = 90 0 A T R > d T = {1 + Z o /(2 Z )} -2 ; Z o vacuum impedance Z = /d sheet resistance d film thickness

4 How to get a huge metal cavity behave like free space with : Z O = 377 Ω, i.e. no standing wave patterns? Install absorbers at the walls! EM anechoic chambers Install absorbers at the walls! Metal walls

5 EM Anechoic Chamber

6 Nano-Metal-Film, a 10 nm metal film vapor deposited on 10 µm polyethylene film

7 d Sheet Resistance Z is Relevant for Wave Propagation if » d : Z = 1/( d) = conductivity d = film thickness = wavelength Foam Nano-Metal Film ( 0.1 S/m) ( 10 6 S/m) d International Patents: G. Nimtz and A. Enders (1998) 2.4 m

8 Absorbing Pyramids: Absorption with Low Reflection E = electric field E Standing Waves in Front of the Metal Wall Z = 0 Nano-film Foam Variation of impedance with position along the line (Smith Diagram) Z

9 Z = Ω 377 Ω Shunt No Reflection /4 E Metal Vacuum Impedance Z 0 = 377 Ω The variation of impedance with position along the line (Smith Diagram)

10

11 R + T + A = 1 of Nano-Film Resistance Angle of incidence = Special Property : For 188 Ω : = 1 TM = 45 0 EM = 45 0 = 90 0 A T R > d

12 e.g. 8 Reflections: R(total) = dB; dB = 10 lg(P 1 /P 2 ) Anechoic trap Transmitter nano-Metal Films Novel Principle, Device under Test: Absorption by Multiple Reflection Metal Wall Nimtz and Panten, Ann. Phys. 19, 53 (2009); Pending Patents, G. Nimtz (2008)

13 Curtains of nano Films instead of Pyramids at one wall as shown next figure

14 EM Anechoic Chamber

15

16 In small Chambers: Ferrite Tiles with Z F Z mm; 30 MHz – 300 MHz (< -20 dB, regulation) Hybrid Absorber: Pyramidal Absorber + Ferrite Tile (30 – MHZ) Metal Wall Z F = Z 0 µ r / r = Z 0 ! Reflection R: R = (n 1 – n 2 )/(n 1 + n 2 ) = (Z F – Z 0 )/Z F + Z 0 )

17

18 Ferrite tiles TDK (Ni-Cu-Zn) :

19 Rain sensing wiper: frustrated total reflection

20 Total Reflection if: sin n 2 /n 1 tot = arc sin(n 2 /n 1 ) Frustration : tot glass n 1 > n 2 air ß

21 The double prisms: frustrated total internal reflection The analog of quantum mechanical tunneling Sommerfeld (1954)

22 Front windshield Prism Rain……. LED Receiver Rain Sensing Wipers: Frustrated total reflexion Rain represents the second prism

23 Nano-Metal Film Absorbers are Broad Band Absorbers, Superior to Carbonized Foam Absorber Incombustible. Non-Toxic. No Hazardous Waste Nano-Metal Film Absorbers on Duty since 1995 Ferrite Tiles, very thin but expensive ( MHz) Frustrated total internal reflection as rain sensing car device. Double Prisms: Newton 1700, BOSE 1900, Sommerfeld 1954 Summing Up :


Download ppt "Classical Electrodynamics Applied in Modern Technology Günter Nimtz Physics Department, University of Cologne 1. Properties of Nano-Metal Films 2. Anechoic."

Similar presentations


Ads by Google