A wideband bandstop filter design utilizing rounded interdigital meander lines and impedance stubs for S and C bands

This paper introduces a novel wideband bandstop filter designed for S and C band applica-tions, utilizing rounded interdigital meander lines and impedance stubs to achieve significant bandwidth and performance improvements. The proposed filter, with compact dimensions of 25 mm x 30 mm, exhibits a wide stopband spanning 4.58 GHz, covering critical frequencies for modern communication systems. The design leverages simple yet effective structural ele-ments, including meandering lines and impedance stubs, to modify the impedance at the ex-citation ports, ensuring efficient band rejection. The filter’s performance was thoroughly val-idated through parametric simulations, followed by the fabrication of a prototype on an FR4 substrate. Measurement results show excellent agreement with simulations, achieving |S₁₁| of-0.56 dB and |S₂₁| of-73 dB at 4 GHz, demonstrating the filter’s ability to deliver high rejection with minimal insertion loss. This BSF not only offers a robust solution for interference miti-gation in S and C bands but also stands out for its ease of fabrication and stability, making it a viable option for integration into compact and high-performance communication systems.