Miniature bandpass filter with a wide stopband up to 40F₀

Abstract

A 243‐MHz narrowband filter with high selectivity performance has been designed. The filter comprises two electromagnetically coupled quasi‐lumped resonators placed into a metal case. Each resonator consists of a tubular capacitor connected in series between two tubular conductors. The measured frequency response of the fabricated filter is presented. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1117–1118, 2012

Implementation of cross couplings in microwave bandpass filters

“…A new quasi‐lumped resonator was recently proposed . It consists of two coaxial tubular conductors each of them is grounded by one of its ends to the metal case.…”

Stripline Bandpass Filter with Wide Stopband and Rejection Level Up to 100 dB

“…One can see that the proposed suspended stripline BPFs have extremely wide and deep stopband. They are inferior only to the latest novel coaxial BPFs but are smaller them in size and are more fabricable.…”

“…One of ways of further widening the stopband lies through developing new structures of resonators whose the second mode frequency many times exceeds the first mode frequency. For example, a fourth‐order BPF based on novel coaxial resonators has the upper stopband at the level of −90 dB which extends up to 47 f 0 . However, from point of view of manufacturability, reliability, and cost such BPFs are significantly worse than constructions based on stripline or microstrip structures.…”

A compact L-band bandpass filter based on SIR coaxial resonators with high multipactor threshold

“…Moreover, it is possible to take advantage of a stepped impedance coaxial resonator (SIR) [9] effect appearing in the folded structure to modulate the size reduction. This principle provided an original concept for a resonator, the SIR coaxial resonator [10][11][12], built from coaxial structures fitted inside one another. The main particularity of this resonator is its construction out of a succession of coaxial sections in cascade, where the ground conductor of one becomes the central core of the next, or vice-versa.…”