Compact Dual-Band Bandpass Filter Using U-Shaped Stepped-Impedance Resonators with Parallel Coupled Structures

Abstract

This paper proposes a dual-band bandpass filter using stepped-impedance resonators (SIRs) with parallel coupled structures. The proposed filter adopts U-shaped SIRs with parallel coupled lines (PCLs) that have interdigital and comb-line shorted ends. The central PCLs build an upper passband and a transmission zero, and the two U-shaped SIRs build a lower passband. Four resonators and coupling structures are theoretically analyzed to derive its scattering parameters. A novel dual-band bandpass filter is designed and fabricated using the induced scattering characteristics. The measured results show that the fabricated dual-band bandpass filter has an insertion loss of less than 1.02 dB in the lower band of 2.45 GHz and of 3.01 dB in the upper band of 3.42 GHz, and a band-to-band isolation of more than 40 dB, from 3.14 to 3.2 GHz. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ⓒ

Dual-Band BPF Based on a Single Dual-Mode Stepped-Impedance Resonator for 4G Systems

“…The second type is based on Stub-Loaded Resonators (SLR) [5][6][7]. Another technique is called the multi-mode Stepped-Impedance Resonators (SIR), which can provide resonances at non-harmonically related frequencies and offers significantly more design freedom in passband control compared to the two previous techniques [8][9][10][11].…”

Simple quad‐band bandpass filter implemented on a 50‐Ω microstrip line

“…Recently, as wireless communication technology has developed, a variety of communication services can be provided by one terminal. Accordingly, communication systems prefer dual‐ and multi‐band microwave components . Up to now, quad‐band bandpass filters (BPFs) using diverse concepts have been studied.…”

“…Accordingly, communication systems prefer dual-and multi-band microwave components. 1,2 Up to now, quad-band bandpass filters (BPFs) using diverse concepts have been studied. To realize quad-band characteristics, short-circuit stubs are embedded into the low-impedance sections of two-sided open-circuit stepped-impedance resonator.…”