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Presented at the COMSOL Conference 2008 Hannover ResonancesinTaperedDouble-Port TEMWaveguides Prof.Dr.-Ing.JensPeterKärst HochschulefürAngewandteWissenschaftundKunst FakultätN COMSOLMultiphysicsKonferenz6.November2008

Presented at the COMSOL Conference 2008 Hannover<br />

ResonancesinTaperedDouble-Port<br />

TEMWaveguides<br />

Prof.Dr.-Ing.JensPeterKärst<br />

HochschulefürAngewandteWissenschaftundKunst<br />

FakultätN<br />

COMSOLMultiphysicsKonferenz6.November2008


Contents Introduction<br />

Analyticalcalculation<br />

Simulation<br />

Measurements<br />

Conclusion<br />

JensPeterKärst ResonancesinTEMWaveguides


Introduction<br />

Analyticalcalculation<br />

Simulation<br />

Measurements<br />

Conclusion<br />

Introduction<br />

Whatarewetalkingabout?<br />

Whatdidwecalculate?<br />

Whycouldthisbeinterestingforyou?<br />

JensPeterKärst ResonancesinTEMWaveguides


Smalltapereddouble-portTEMwaveguides<br />

◮ µTEMcell,PTB,German�E-fieldstandard<br />

◮ µC 3 cell,proposedCircularCoaxialCalibrationcell<br />

JensPeterKärst ResonancesinTEMWaveguides


Mechanicalconstruction,CrawfordTEMcell<br />

◮ Rectangularcrosssection<br />

◮ Flatinnerconductor(Septum)<br />

JensPeterKärst ResonancesinTEMWaveguides


Mechanicalconstruction,µC 3 cell<br />

◮ Circularcrosssection<br />

◮ Roundinnerconductor(Septum)<br />

JensPeterKärst ResonancesinTEMWaveguides


Introduction<br />

Analyticalcalculation<br />

Simulation<br />

Measurements<br />

Conclusion<br />

Analyticalcalculation<br />

Generalizedtelegraphist’sequations<br />

Resonancecalculation<br />

JensPeterKärst ResonancesinTEMWaveguides


Fieldmodes,transversal�E<br />

TEMmode<br />

0.5<br />

0.4<br />

0.3<br />

0.2<br />

0.1<br />

0<br />

−0.1<br />

−0.2<br />

−0.3<br />

−0.4<br />

TEM−Mode<br />

−0.5 0 0.5<br />

JensPeterKärst ResonancesinTEMWaveguides


Fieldmodes,transversal�E<br />

TM01mode<br />

0.5<br />

0.4<br />

0.3<br />

0.2<br />

0.1<br />

0<br />

−0.1<br />

−0.2<br />

−0.3<br />

−0.4<br />

E−Mode, k (E)<br />

/(2a) = 11.0242<br />

c<br />

−0.5 0 0.5<br />

JensPeterKärst ResonancesinTEMWaveguides


Fieldmodes,transversal�H<br />

TM01mode<br />

0.5<br />

0.4<br />

0.3<br />

0.2<br />

0.1<br />

0<br />

−0.1<br />

−0.2<br />

−0.3<br />

−0.4<br />

E−Mode, k (E)<br />

/(2a) = 11.0242<br />

c<br />

−0.5 0 0.5<br />

JensPeterKärst ResonancesinTEMWaveguides


TransmissionlinemodelofataperedTEMwaveguide<br />

Setup<br />

V<br />

ZC<br />

TEMmode<br />

Z (TEM)<br />

W<br />

V·u<br />

V (TEM)<br />

outerconductor<br />

innerconductor(septum)<br />

coupling coupling<br />

I (TEM)<br />

γ (TEM) ,Z (TEM)<br />

W<br />

ZC<br />

0z0 z z<br />

(TE)<br />

c z (TM)<br />

c zK zsym zL<br />

JensPeterKärst ResonancesinTEMWaveguides<br />

Z (TEM)<br />

W


TransmissionlinemodelofataperedTEMwaveguide<br />

TEMmode<br />

Z (TEM)<br />

W<br />

V·u<br />

TEmode<br />

Z (TE)<br />

W (z(TE)<br />

V (TEM)<br />

CTEM,TE<br />

undercutoff overcutoff<br />

I (TEM)<br />

γ (TEM) ,Z (TEM)<br />

W<br />

V (TE)<br />

CTE,TEM<br />

I (TE)<br />

γ (TE) ,Z (TE)<br />

W<br />

Z (TEM)<br />

W<br />

c ) Z (TE)<br />

JensPeterKärst ResonancesinTEMWaveguides<br />

W


TransmissionlinemodelofataperedTEMwaveguide<br />

TEMmode<br />

Z (TEM)<br />

W<br />

V·u<br />

TMmode<br />

V (TEM)<br />

Z (TM)<br />

W (z(TM)<br />

Cp,TM<br />

I (TEM)<br />

γ (TEM) ,Z (TEM)<br />

W<br />

V (TM)<br />

CTM,q<br />

γ (TM) ,Z (TM)<br />

W<br />

I (TM)<br />

Z (TEM)<br />

W<br />

c ) Z (TM)<br />

undercutoff overcutoff undercutoff<br />

JensPeterKärst ResonancesinTEMWaveguides<br />

W


TransmissionlinemodelofataperedTEMwaveguide<br />

TMmode<br />

Setup<br />

Z (TM)<br />

W (z(TM)<br />

V<br />

ZC<br />

V (TM)<br />

undercutoff overcutoff undercutoff<br />

outerconductor<br />

I (TM)<br />

c ) Z (TM)<br />

γ (TM) ,Z (TM)<br />

W<br />

innerconductor(septum)<br />

W<br />

coupling coupling<br />

ZC<br />

0z0 z z<br />

(TE)<br />

c z (TM)<br />

c zK zsym zL<br />

JensPeterKärst ResonancesinTEMWaveguides


Generalisedtelegraphist’sequationsformodep<br />

Usingpropagationconstantγ (p) andwaveimpedanceZ (p)<br />

W :<br />

dV (p)<br />

dz =−γ(p) (z)Z (p)<br />

W (z)I (p) ∞�<br />

(z) + Cpq(z)V (q) (z)<br />

dI (p)<br />

dz =−γ(p) (z)<br />

Z (p)<br />

W (z)V (p) (z)−<br />

q=1<br />

∞�<br />

Cqp(z)I (q) (z)<br />

q=1<br />

Neglectingmodecouplingusingwavenumberk=ω √ µε:<br />

d 2 V (TE)<br />

dz<br />

d 2 I (TM)<br />

k<br />

= 2<br />

k<br />

= 2<br />

dz<br />

�<br />

k (TE)2<br />

c (z)−k 2�<br />

V (TE)<br />

k (z)<br />

�<br />

k (TM)2<br />

c (z)−k 2�<br />

I (TM)<br />

k (z)<br />

JensPeterKärst ResonancesinTEMWaveguides


I (TM) (z)ofTM01atresonanceinaµC 3 -cell<br />

I (TM) zsym<br />

0.05<br />

0<br />

−0.05<br />

0 0.02 0.04 0.06 0.08 0.1<br />

Firstresonanceatfres =4.456GHz<br />

JensPeterKärst ResonancesinTEMWaveguides<br />

z<br />

m


I (TM) (z)ofTM01atresonanceinaµC 3 -cell<br />

I (TM) zsym<br />

0.05<br />

0<br />

−0.05<br />

0 0.02 0.04 0.06 0.08 0.1<br />

Secondresonanceatfres =5.001GHz<br />

JensPeterKärst ResonancesinTEMWaveguides<br />

z<br />

m


Introduction<br />

Analyticalcalculation<br />

Simulation<br />

Measurements<br />

Conclusion<br />

Simulation<br />

MATLAB/NAGsimulation<br />

FEMLABsimulation<br />

JensPeterKärst ResonancesinTEMWaveguides


Simulationusinggeneralisedtelegraphist’sequations<br />

1<br />

0.8<br />

0.6<br />

0.4<br />

0.2<br />

0<br />

0 1 2 3 4 5 6<br />

MATLABwithNAGtoolbox,S21,range0


Longitudinalcomponentoftheelectricfield�E<br />

Belowresonanceatf =1GHz<br />

JensPeterKärst ResonancesinTEMWaveguides


Longitudinalcomponentoftheelectricfield�E<br />

AtfirstTM01resonancefTM011 =4.4GHz<br />

JensPeterKärst ResonancesinTEMWaveguides


Longitudinalcomponentoftheelectricfield�E<br />

AtsecondTM01resonancefTM012 =4.9GHz<br />

JensPeterKärst ResonancesinTEMWaveguides


SimulationusingFEMmodel,FEMLABwithRFtoolbox<br />

1<br />

0.9<br />

0.8<br />

0.7<br />

0.6<br />

0.5<br />

0.4<br />

0.3<br />

0.2<br />

0.1<br />

0<br />

0 1 2 3 4 5 6<br />

x10 9<br />

S11,S21,range0


Introduction<br />

Analyticalcalculation<br />

Simulation<br />

Measurements<br />

Conclusion<br />

Measurements<br />

Comparisonwithanalyticalcalculations<br />

Comparisonwithsimulationresults<br />

JensPeterKärst ResonancesinTEMWaveguides


SimulationusingFEMmodel,FEMLABwithRFtoolbox<br />

1<br />

0.8<br />

0.6<br />

0.4<br />

0.2<br />

0<br />

0 1 2 3 4 5 6<br />

S11,S21,range0


Introduction<br />

Analyticalcalculation<br />

Simulation<br />

Measurements<br />

Conclusion<br />

Conclusion<br />

JensPeterKärst ResonancesinTEMWaveguides


Conclusion<br />

◮ Ananalyticalmethodforthecalculationofresonant<br />

frequencieshasbeenpresented<br />

◮ Acomparisonofresultsobtainedusingtwodifferent<br />

simulationmethods<br />

1. Generalisedtelegraphist’sequations(MATLABwithNAG<br />

toolbox)<br />

2. FEMmodel(FEMLABwithRFtoolbox)<br />

andmeasurentsshowscloseagreement<br />

◮ Simulationscanbebenchmarkedusingthisanalyticalmethod<br />

JensPeterKärst ResonancesinTEMWaveguides

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