M. Hajebi, M. Danaeian, E. Zarezadeh,
Volume 13, Issue 3 (9-2017)
Abstract
Using composite right-left handed (CRLH) transmission line concept, a novel miniaturized dual notch band filter (DNBF) is proposed. The suggested DNBF consists of an interdigital transmission line (ITL), split ring resonators (SRRs) and complementary split ring resonators (CSRRs). Since the resonance frequency of the SRRs and CSRRs are quite independent of each other, the dual notch bands of the proposed filter can be separately controlled and shifted by changing the dimension of the SRRs and CSRRs. In this paper, the reject bands are designed for WLAN (2.4 GHz) and WiMAX (3.5 GHz) to reject these frequency bands from the ultra-wide band communication systems. The simulation results show that the transmission response has more than 32 dB rejections near each band. To validate the design concept, the proposed NBPF has been fabricated and tested. Experimental verification is provided and good agreement has been found between simulation and measurement. To the best of our knowledge, the proposed NBPF is more compact in comparison with other reported filters.
Gauravkumar Asari,
Volume 22, Issue 3 (9-2026)
Abstract
Bandpass filters (BPFs) are critical components in 5G radio-frequency front-end systems, where wide bandwidth, low insertion loss, and compact size are simultaneously required. In this paper, a metamaterial-inspired wideband BPF based on Complementary Split Ring Resonators (CSRRs) loaded with a dumbbell-shaped Defected Ground Structure (DGS) is proposed for mid-band 5G applications centered at 4.7 GHz. Unlike conventional designs that rely on commercial electromagnetic solvers, the proposed filter is developed and analyzed using a fully open-source electromagnetic simulation framework based on Open EMS, enabling cost-effectiveness and design reproducibility. The design evolution from a single-ring CSRR to a triple-ring configuration is systematically presented to enhance magnetic coupling and bandwidth. The incorporation of a dumbbell-shaped DGS further modifies the ground current distribution, leading to improved selectivity and reduced insertion loss. The optimized filter achieves a fractional bandwidth of approximately 43%, a minimum insertion loss of 0.72 dB, and a return loss better than -35 dB using a low-cost FR-4 substrate. Comprehensive parametric analysis, metamaterial characterization, group delay response, and electromagnetic field distribution are provided to validate the proposed approach. The results demonstrate that the open-source Open EMS-based methodology can achieve performance comparable to commercial solvers, offering an accessible and reliable design pathway for next-generation microwave filter development.
