Design of a Novel Compact Microstrip Triple-Band Bandpass Filter Utilizing a Symmetric Stepped-Impedance Resonator (SIR) Structure

Khajavi, Morteza; Farshidi, Ebrahim; Soroosh, Mohammad; Ajabi, Shahrzad

doi:10.22075/mseee.2026.40893.1265

Design of a Novel Compact Microstrip Triple-Band Bandpass Filter Utilizing a Symmetric Stepped-Impedance Resonator (SIR) Structure

Document Type : Research Article

Authors

Morteza Khajavi

Ebrahim Farshidi

Mohammad Soroosh

Shahrzad Ajabi

Department of Electrical Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran.

10.22075/mseee.2026.40893.1265

Abstract

In this research, an innovative design of a tri-band microstrip bandpass filter is presented, utilizing a combination of Stepped-Impedance Resonators (SIRs). The design methodology of the proposed filter is based on a systematic and goal-oriented approach. In the initial design phase, a specific topology is employed as the baseline structure. Subsequently, through a targeted process involving several stages of optimization and structural/parametric modifications to the baseline design, the original single-band structure is effectively evolved into a tri-band structure with desirable frequency characteristics and quality factors. The final filter designed in this study features three passbands with central frequencies of 5 GHz, 7.8 GHz, and 14.5 GHz. The passband insertion losses are 1.4 dB, 0.7 dB, and 0.6 dB, respectively, while the return losses are 41.2 dB, 21 dB, and 25.1 dB, respectively. The quality factors of the passbands are 8.4, 7.9, and 26.3, respectively. This design offers the advantages of a compact size, simple structure, and multiband operation.

Keywords

Triple-band bandpass filter

Resonator

Stepped-impedance resonator (SIR)

Insertion loss

Return loss

Subjects

Communication System

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