A Compact Ultra-Wideband Multimode Bandpass Filter With Sharp-Rejection Using Stepped Impedance Open Stub and Series Transformers

Kumar, Kanaparthi V. Phani; Velidi, Vamsi Krishna; Rajkumar, R.; Rao, T. Rama

doi:10.1109/tcsii.2022.3192512

Cited by 3 publications

(1 citation statement)

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“…Recently, several models of filters with wideband and multiband frequency response have been developed [4][5][6][7]. It is common to use coupled line topologies [8], multiple transmission poles and zeros [9], stepped-impedance resonators (SIR) [10] and classical geometries (square/ split-ring) [11]. In [12] a bandstop filter with high frequency selective response is presented.…”

Section: Introductionmentioning

confidence: 99%

A new tunable bandstop filter square-ring resonator using varactor diodes

Duarte Júnior,

da Silva Neto,

Gomes d’Assunção

2023

PLoS ONE

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This work presents the development of a bandstop filter with a tunable response. Varactor diodes are used as control elements. Studies and investigations demonstrate the influence of the variable capacitance on the input admittance and on the S-parameters frequency responses of the proposed square-ring resonator geometry. The design of the square-ring resonator is based on mathematical modeling of ideal transmission lines, considering parameters of characteristic admittance and electrical length for odd and even excitation modes. Based on S-parameters in ports, an equivalent circuit model of the resonator geometry is presented. The corresponding results are compared with numerical simulations. Comparative analyses are presented in order to guide the process of optimizing the physical dimensions of the layout. A prototype with dimension 0.0272 λg2 was designed, fabricated, and tested. As a measured result, a filter with two rejection bands was obtained, the first at 0.6–1.15 GHz and the second at 1.71–2.28 GHz, with 63.0 and 29.0% tuning range, respectively. In comparison with bandstop filters from the literature, the proposed reconfigurable filter presents a larger tuning range for the first band, sufficient inband rejection levels for several applications, and reduced physical dimensions. The proposed configuration is an attractive reconfigurable filtering device for use in modern communication systems operating below 3.0 GHz.

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