A minimized dual-band bandpass filter using series λ/4 resonators and open stub line

Abstract

A compact dual-band bandpass filter (BPF) design using series λ/4 resonators and open stun line was proposed in this paper. The proposed circuit was implemented with a multilayer structure by low-temperature co-fired ceramic. The proposed device has two passband responses with low insertion loss and multiple transmission zeros (TZ) to have wide stopband with high reject level. Through the proposed schematic, a dual-band BPF with stopband up to 4.5 f 1 (central frequency of the first passband) can be easily designed. The overall dimensions of dual-band bandpass of dual-band bandpass filter are 1.6 mm (L) − 0.8 mm (W) − 0.7 mm (H).