Novel Defected Ground Structure and Two-Side Loading Scheme for Miniaturized Dual-Band SIW Bandpass Filter Designs

• Published in: IEEE microwave and wireless components letters Vol. 25; no. 4; pp. 217 - 219
• Main Authors: Xu, Shanshan, Ma, Kaixue, Meng, Fanyi, Yeo, Kiat Seng
• Format: Journal Article
• Language: English
• Published: IEEE 01.04.2015
• Subjects: Back-to-back E-shaped; Band theory; Band-pass filters; bandpass filter (BPF); Bandpass filters; complementary open-loop resonator (COLR); complementary split ring resonator (CSRR); Couplings; defected ground structure (DGS); Design engineering; Dual band; dual-band filters; Grounds; Loading; Microwaves; miniaturization; Noise levels; Optical ring resonators; Poles; Resonant frequency; substrate integrated waveguide (SIW); Substrates; Wave propagation
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2015.2400916

This letter reports a novel back-to-back E-shaped defected ground structure (DGS) and two-side loading scheme for miniaturized dual-band substrate integrated waveguide (SIW) bandpass filter (BPF) designs. The SIW loaded by novel DGS supports evanescent-mode wave propagation below the cut-off frequency of SIW, while achieves two transmission poles at the passband and two controllable transmission zero points. Furthermore, the novel loading scheme by loading different-sized DGS resonators on two sides of SIW is proposed for dual-band BPF designs. To validate the design and analysis, a 2.4/5.2 GHz filter prototype was designed. In good agreement with theoretical results, the measured results of the dual-band filter achieve insertion losses of 3.6 and 3.1 dB, and fractional bandwidths of 5.8% and 6.45% at 2.4 and 5.2 GHz, respectively. The filter size is only 408 mil × 420 mil.