Classical Electrodynamics Applied in Modern Technology Günter Nimtz Physics Department, University of Cologne 1. 2. 3. 4. 5. Properties of Nano-Metal Films Anechoic EMC Chambers: Pyramidal Absorber Absorption by Anechoic Traps: Reflecting Curtains Ferrite Tile Absorber……….Hybrid Absorbers Rain Sensing Wipers: Frustrated Total Internal Reflection = Tunneling 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) R A T R+T+A=1 of Nano-Film Resistance Angle of incidence = = 900 > d T = {1 + Zo/(2 Z)}-2 ; TM = 450 Zo vacuum impedance Z =/d sheet resistance d film thickness EM = 450 How to get a huge metal cavity behave like free space with : ZO = 377 Ω, i.e. no standing wave patterns? Install absorbers at the walls! EM anechoic chambers Metal walls Install absorbers at the walls! EM Anechoic Chamber Nano-Metal-Film, a 10 nm metal film vapor deposited on 10 µm polyethylene film Sheet Resistance Z is Relevant for Wave Propagation if » d : Z = 1/( d) d d = conductivity d = film thickness = wavelength Foam ≈ 10-7 Nano-Metal Film (≈ 0.1 S/m) (≈ 106 S/m) 2.4 m International Patents: G. Nimtz and A. Enders (1998) Standing Waves in Front of the Metal Wall Variation of impedance Z with position along the line (Smith Diagram) Absorbing Pyramids: Absorption with Low Reflection Z=0 Foam E Nano-film E = electric field Vacuum Impedance Z0 = 377 Ω Metal E /4 Z=Ω ≈ 377 Ω Shunt No Reflection The variation of impedance with position along the line (Smith Diagram) R A T R+T+A=1 of Nano-Film Resistance Angle of incidence = = 900 >d Special Property : TM = 450 For 188 Ω: 0.25 + 0.25 + 0.5 = 1 EM = 450 Novel Principle, Device under Test: Absorption by Multiple Reflection e.g. 8 Reflections: R(total) = 0.258 - 48 dB; dB = 10 lg(P1/P2) Transmitter Anechoic trap nano-Metal Films Metal Wall Nimtz and Panten, Ann. Phys. 19, 53 (2009); Pending Patents, G. Nimtz (2008) Curtains of nano Films instead of Pyramids at one wall as shown next figure EM Anechoic Chamber In small Chambers: Ferrite Tiles with ZF ≈ Z0 6.3 mm; 30 MHz – 300 MHz (< -20 dB, regulation) Hybrid Absorber: Pyramidal Absorber + Ferrite Tile (30 – 18 000 MHZ) ZF = Z0 µr/r = Z0 ! Reflection R: R = (n1 – n2)/(n1 + n2) = (ZF – Z0)/ZF + Z0) Metal Wall Ferrite tiles TDK (Ni-Cu-Zn) : Rain sensing wiper: frustrated total reflection glass n1 > n2 air Total Reflection if: sin n2/n1 ß tot = arc sin(n2/n1) Frustration : tot The double prisms: frustrated total internal reflection The analog of quantum mechanical tunneling Sommerfeld (1954) Rain Sensing Wipers: Front windshield LED Frustrated total reflexion Rain represents the second prism Prism Receiver Rain……. Summing Up : • 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 (30-400 MHz) • Frustrated total internal reflection as rain sensing car device. • Double Prisms: Newton 1700, BOSE 1900, Sommerfeld 1954