Compact quasi-elliptic waveguide filters on contoured resonant diaphragms

ABSTRACT

We present a new type of waveguide bandpass quasi-elliptic filter whose resonators are implemented by thin transverse resonant diaphragms with an aperture in the form of a rectangular window with two metal L-shaped ridges. It is shown that the amplitude–frequency characteristics of such contoured diaphragms demonstrate the frequencies of parallel and series resonances simultaneously. We also construct equivalent circuits of the third and fifth-order elliptic filters and provide a computer simulation of the diaphragms satisfying the amplitude–frequency characteristics of each resonator. It is shown that for waveguide elliptic filters, some resonators can be located on one resonant diaphragm, which further reduces the length of the filter. The synthesis results of compact quasi-elliptic filters for WR137 rectangular waveguide with the central frequency of 6.5 GHz and bandwidth of 7.5% are presented. The total length of the filters is 34 mm for third order and 64 mm for fifth order, respectively.

KEYWORDS:

• Rectangular waveguide
• bandpass filter
• quasi-elliptic filter
• compact geometry
• contoured resonant diaphragm

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

V. Zemlyakov http://orcid.org/0000-0002-3932-6759

Additional information

Funding

The work of the first author was supported by the Southern Federal University. The work of the second author was partially supported by the Joint NSFC-ISF Research Program, jointly funded by the National Natural Science Foundation of China and the Israel Science Foundation (No. 11561141001).

Notes on contributors

V. Zemlyakov

Prof. V. Zemlyakov received his B.Sc. from Rostov State University (Russia) in 2000, M.Sc. from Karlsruhe University of Applied Sciences (Germany) in 2003, Ph.D. from Rostov State University (Russia) in 2005 and D.Sc. from Southern Federal University (Russia) in 2015. He is currently a Professor with the Faculty of Physics of Southern Federal University, Russia. His research interests include electrodynamics, computer simulation, microwave filters and diplexers.

M. Tyaglov

Dr. M. Tyaglov received B.Sc., M.S., and Ph.D. degrees from Rostov State University, Rostov-on-Don, Russia, in 1999 and 2001, respectively, and Ph.D. degree from Berlin Technical University, Berlin, Germany, in 2009, in classical analysis. Currently, he is a Special Researcher with the School of Mathematical Sciences of Shanghai Jiao Tong University. His research interests include classical and complex analysis, orthogonal polynomials, stability theory and filter design.

V. Shevchenko

Prof. V. Shevchenko received his Ph.D. from Rostov State University (Russia) in 1993 and D.Sc. from Southern Federal University (Russia) in 2003. From 2009 to 2014 he was a Professor with the faculty of Physics of Southern Federal University, Russia. He is currently a Chief of research activities with the Scientific Research Institute “Gradient”, Russia. His research interests include radio-engineering, microwave CAD, antenna systems.