Compact Wideband BPF With Wide Stopband Using Substrate Integrated Defected Ground Structure

• Published in: IEEE microwave and wireless components letters Vol. 31; no. 4; pp. 353 - 356
• Main Authors: Zhou, Jie, Rao, Yunbo, Yang, Dongxia, Qian, Huizhen Jenny, Luo, Xun
• Format: Journal Article
• Language: English
• Published: IEEE 01.04.2021
• Subjects: Band-pass filters; Bandpass filter (BPF); compact; Couplings; Equivalent circuits; Harmonic analysis; Passband; substrate integrated defected ground structure (SIDGS); Substrates; wide stopband; Wideband
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2021.3053756

In this letter, a compact wideband bandpass filter (BPF) with a wide stopband is proposed based on the substrate integrated defected ground structure (SIDGS) and folded stepped-impedance resonator (FSIR). Such a SIDGS resonator can not only allocate a specific resonance with compact size but also introduce the different harmonic positions compared with a traditional microstrip line resonator. Meanwhile, due to the discrepant harmonic positions of proposed SIDGS and FSIR, a wide stopband response can be achieved using a compact stacked-coupled scheme. To verify the mechanism, a miniaturized wideband BPF operating at 1.69 GHz (i.e., <inline-formula> <tex-math notation="LaTeX">f_{0} </tex-math></inline-formula>) is implemented and fabricated. A measured wide stopband up to 11.8<inline-formula> <tex-math notation="LaTeX">f_{0} </tex-math></inline-formula> with a 20-dB rejection level is achieved.