Dual-band bandpass filter design using miniaturized spiral scheme

Abstract

A compact dual‐band bandpass filter using two sets of spiral resonators and loaded spiral open‐stub is proposed. The dual‐band resonances are introduced by the quarter‐wavelength (λ/4) spiral resonator and λ/2 asymmetrical spiral stepped‐impedance resonator, respectively. Then, the loaded spiral open‐stub tapped on the λ/4 spiral resonator is utilized for spurious shifting close to transmission zero, which can lead to spurious suppression for extended upper stopband. Finally, a dual‐band bandpass filter with good performance and size miniaturization is fabricated and verified experimentally. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:997–999, 2014

Miniaturised dual‐band filter with high selectivity using split ring scheme

“…The two passbands in [3] can be designed separately and changed individually with the shortage of poor insertion losses. Otherwise, to miniaturise the size of BPFs, many new microstrip structures have been proposed, such as spiral scheme [5], folded SIR [6] and modified SIR [7].…”

“…Introduction: Rapid development in dual-band wireless communications has been continuing to promote the design and exploration of advanced bandpass filters (BPFs) with better functionalities in recent years. As a result, various design methods for the dual-band BPFs have been presented [1][2][3][4][5][6][7]. Properly introducing two individual resonators is an effective way to approach dual-band filters [1].…”

A miniature hext‐band bandpass microstrip filter using stepped‐impedance spiral resonators

“…These MBPFs should be characterized by compactness, low‐cost fabrication process, suppressed spurious responses, low insertion loss in sub‐bands, high selectivity, less complexity in designs, and having a sufficient number of sub‐bands specified for various wireless standards. In the literature, intensive research efforts by the scientific community have focused, to achieve numerous design and analysis techniques, to realize MBPFs, having aforementioned characteristics, including dual‐, triple‐, and quad‐bands . However, comparatively, a limited research work has been conducted to date to achieve quint‐ and hext‐band filters and beyond.…”