Design of a new compact dual-mode multiband bandpass filter using multi-armed ring-open-loop resonators without coupling gaps

Abstract

In this article, we proposed at first step a new compact dual-mode bandstop filter with broad stopband and low insertion loss in the passband using one ring resonator.Based of this microstrip ring resonator, a novel type of multibandpass filters is proposed. The idea of the proposed filters is to engineer the transmission band using multireject band resonators, which are implemented using multi-armed open-loop resonators that are directly coupled to the input/output ports. Each resonator pair of arms creates a reject band in the transmission response. By properly adjusting the multireject bands, appropriate multitransmission bands are created. The idea was verified by designing three different filters with multibandpass response. The designed and fabricated filters have compact size with good agreement between the measured and simulated responses. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2668–2672, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25576