A novel modified complementary metamaterial resonator based dual-band bandpass quasi-elliptic filter using half-mode SIW cavity with wide stopband rejection for wireless communication applications

This article presents a novel dual-band metamaterial bandpass quasi-elliptic filter (DBBPF) for wireless communication applications, addressing the critical need for compact, high-performance multi-band filters in modern systems. The proposed filter leverages substrate-integrated waveguide cavity (SIWC) technology combined with innovative complementary metamaterial resonators to achieve significant miniaturization while maintaining excellent electrical performance. The filter’s design incorporates four complementary resonators of modified rectangular shape (CMSRR) on the metalized top face, generating targeted operating bands below the SIW cutoff frequency. To control their resonances, the size of each CMSRR is optimized for electrical dimensions of just 0.154 ${\lambda }_0\times$ 0.115 ${\lambda }_0\times$ 0.028 ${\lambda }_0$. We present a comprehensive analysis of both full mode (FMSIWC) and half mode (HMSIWC) configurations, demonstrating dual-bandpass behavior with central frequencies at 5.79 and 9.82 GHz for FMSIWC, and 5.72 and 9.74 GHz for HMSIWC. The electromagnetic behavior of the basic cell of the filter is analyzed based on the frequency characteristics of its permittivity and permeability. A parametric study according to the location of the metamaterial resonators in the filter is conducted to have the optimized dimensions. Additionally, the confinement of the electric field in the two filter configurations is discussed to better understand their behavior. The fabricated HMSIWC filter, implemented on an FR4-Epoxy substrate measuring only 54.60 × 25.75 × 1.5875 mm³, achieves remarkable miniaturization while maintaining desired performance characteristics. Experimental results validate the simulated performance, demonstrating excellent agreement for both configurations. Key performance metrics include fractional bandwidths of 3.77 and 6.98 %, and insertion losses of 1.33 dB and 2.14 dB for the two passbands in the HMSIWC design. This work advances the state-of-the-art SIW filter design by combining half-mode techniques with optimized CMSRR structures, resulting in a compact, high-performance dual-band filter. The proposed DBBPF’s simple design and small form factor make it an ideal candidate for integration into various wireless communication systems, particularly where space constraints are critical.