No abstract

Abstract-A novel compact microstrip resonator based on interdigital structure is proposed. The resonator has several times higher quality factor than similar resonators presented earlier. It is shown that the size of the resonator can be significantly reduced with substantial increase in quality factor by incrementing the number of pins in the interdigital structure. A 4-pole bandpass filter with central frequency 900 MHz and an overall size 4.6 mm 10.0 mm was designed and fabricated on the base of the proposed structure. The measured upper stopband of the filter was found to be up to at the level 40 dB.Index Terms-Bandpass filter (BPF), interdigital resonator, microstrip, microstrip resonator.

A new quasi-lumped suspended-substrate stripline structure admitting implementation of miniature highly selective narrowband filters is studied. Appreciable improvement of the device selectivity is achieved with supplementary strip conductors introduced between the resonators, which induce attenuation poles near both passband edges. Furthermore, these supplementary conductors reducing the coupling between the resonators allow diminishing the interresonator spacing and the total size. A four-resonator filter is synthesized using the intelligence optimization method. Experimental results of the manufactured filter are presented.

A dual‐mode microstrip resonator whose strip conductor is partially split from its one end by a longitudinal slot has been studied. The resonator has two fundamental modes, even and odd ones. The difference of their frequencies is controlled by varying the slot length. Based on such resonators, original structures of a diplexer and passband filters including dual‐band have been designed. Measured performances of their fabricated prototypes prove applicability of designed devices in microwave engineering. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2186–2190, 2013