Multi-conductor coaxial cavity resonators for miniaturization of UHF bandpass filters

Abstract

In this paper, we present the compact bandpass cavity filters for UHF range. We investigate the properties of coaxial resonators with various numbers of tubular posts from one to four. We show that the resonant frequency can be four times smaller for the four-post resonator in comparison with the single post resonator with the same cavity dimensions. We synthesized and manufactured fifth-order bandpass cavity filter on four-post coaxial resonators for the 690–806 MHz frequency range with 20-dB return loss. The filter dimensions were 30 mm × 44 mm × 127 mm. We also synthesized and manufactured the fifth-order bandpass cavity filter on four-post coaxial resonators with inductive and capacitive cross-coupling between first and fifth resonators to provide transmission zeros in amplitude–frequency characteristic in lower- and upper-frequency band, respectively. Comparison with the standard double-post coaxial cavity filters demonstrates more than 30% volume reduction with similar transmission characteristics.

KEYWORDS:

• UHF range
• cavity filter
• coaxial resonator
• multi-conductor
• cross-coupling
• compact

Acknowledgments

This research is supported by the Southern Federal University.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Southern Federal University.

Notes on contributors

Zi Meng Li

Zi Meng Li has received a Bachelor's degree in Mechanical & Electrical Integration from Shaanxi University Of Science & Technology, Xi’an, China, in 2006. He is currently the CEO of Guangdong Sigtenna Communication Technology Co., Ltd. in China. His current research interests include the development of multi-beam antennas and multiband antennas for wireless communication.

Victor A. Sledkov

Victor A. Sledkov has received an M.S. degree in radiophysics and a Ph.D. degree in radiophysics from Southern Federal University, Rostov-on-Don, Russia, in 1971 and 1975, respectively. He is currently a Chief scientist of Guangdong Sigtenna Communication Technology Co., Ltd., Dongguan, China. His current research interests include the development of multi-beam and multiband antennas for wireless communication.

Viacheslav V. Zemlyakov

Viacheslav V. Zemlyakov received and M.S. degree in physics, a Ph.D. and a Dr.Sc. degrees in radiophysics and electronics from Southern Federal University, Rostov-on-Don, Russia, in 2002, 2005, and 2015, respectively. He is currently a Professor at Southern Federal University, Rostov-on-Don, Russia. His research interests include numerical modeling, synthesis, and analysis of microwave frequency-selective systems.