ka-band gap waveguide coupled-resonator filter for radio link

7/28/2019 Ka-Band Gap Waveguide Coupled-Resonator Filter for Radio Link

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Sara Sofía Abril Guevara (261689)Roberto Salamanca Girón (261878)

Diego Velandia Cárdenas (261765)



GLOSSARY◦

Ka-Band

INTRODUCTION◦ Gap waveguide◦ Diplexer

DESIGN AND SPECIFICATIONS◦ Filter Specifications◦ Curve Specifications

SIMULATED CIRCUITS

PROTOTYPE MEASUREMENTS

CONCLUSIONS

REFERENCES

2



IEEE defined frequency band between 26.5 GHz

and 40 GHz.

It is widely used in satellite communications.

AdvantageHigh bandwidth -> good data flux

DisadvantageRequires high power devices;

highly environmental noise sensitive.



Waveguidearrangement verysimilar to Ridgeconfiguration.

Gap waveguideshow low loss buthas a high costand difficulty tointegrate.



Waves propagate: TEM-modefollowing ridges/strips withinthe ridge and microstrip gapwaveguides.

This texture creates a highimpedance condition at thesurface which in turn forces acut-off for the parallel-platemodes

Wave propagation forbbidenbetween these plates.Distance<λ/4



Diplexer: Critical componentHigh requierements: Fullfilled by WG

Very low insertion loss and high selectivity to rejectsignals

The RF front ends for point-to-point microwave linkscould benefit from the gap waveguide technology tointegrate active and passive parts in the same module



Tradicionally constructed using RWG, but they representa higher cost, complexity and size.

Must be connected to electronic modules, which contains active

components and MMIC

Gap waveguide technology integrate passive and activecomponents in the same module, even the anthena

Package microstrip circuits without creating cavity resonances

They can be used as transmission lines to realize passive components,such as filters and couplers

Gap waveguides supplies new technologies



Coupling coefficient of intercoupled resonatorsand the external qualityfactors of the input and

output resonators.

The selectivity of a filter

increases with the numberof resonant sections



Any filter can be described by three fundamental variables:

• The synchronous tuning frequency of each resonator, f0• The coupling between adjacent resonators, K• The singly loaded or external Q of the first and last resonators, Qex



From the Chebyshev filter's iteration parameters, it's quitesimple getting the operation order, from which it's alsopossible to derive the prototype elements values, andfurthermore, the coupling coefficients and external qualityfactors.



As usual practice, a BW 20% wider than

the required 1.5% has been considered for thedesign.



In order to determine the filter geometry, design curves have tobe previously calculated. Such curves describe therelationship between the filter parameters, i.e., couplingcoefficient between resonators (K) and coupling to theexternal network or external quality factor (Qex), and someparameters describing the filter geometry.



Results show

optimumperformanceat qualityfactor

Qex=44.27And centralfrequency of f0 = 37.37

GHz

=20

−3



As can be seen, specifications are satisfied. Return loss better than−17 dB and insertion loss less than 1.5 dB within the pass-band

were obtained. Isolation higher than 70 dB within the stop-band isalso satisfied. Insertion loss at the central frequency is below 1 dB.

=



Two prototype were built. One using aluminumas conductor and the other with silver plates.



Gap resonators show similar performance torectangular waveguide, slightly better in terms of insertion loss.

Waveguide filters are high-performance, butdifficult to integrate with active components.

Coupled-resonator filters in groove gapwaveguide are cost effective, since they areformed in the gap between two parallel-metalplates. And moreover, they are less sensitive totemperature drift, as they are based open cavities

that allow airing and cooling. Silver plates showed better performance than

aluminum plates in terms of loses.



[1] Alos, E. A. ; Zaman, A. U. ; Kildal, P.-S. “Ka-Band Gap Waveguide Coupled-Resonator Filterfor Radio Link Diplexer Application” Components, Packaging and Manufacturing Technology, IEEETransactions on Volume: PP , Issue: 99 Digital Object Identifier:10.1109/TCPMT.2012.2231140 Publication Year: 2013 ,

Page(s): 1

[2] D. Deslandes and K. Wu, “Integrated microstrip andrectangular waveguide in planar form,” IEEE Microw. Wireless Compon. Lett., vol. 11, no. 2, pp. 68–70, Feb. 2001.

[3] P.-S. Kildal, E. Alfonso, A. Valero-Nogueira, and E. Rajo-Iglesias, “Local metamaterial-based waveguides in gapsbetween parallel metal plates,” IEEE Antennas Wireless Propag.Lett., vol. 8, pp. 84–87, Apr. 2009.

ka-band gap waveguide coupled-resonator filter for radio link

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