Dual-Band Bandpass Filter Based on Electromagnetic Coupling of Twin Square Metamaterial Resonators (SRRs) and Complementary Resonator (CSRR) for Wireless Communications

In this paper, a dual-band bandpass microwave filter (DBBPF) is presented. This filter is based on the electromagnetic coupling between two identical split-ring metamaterial resonators (SRRs) (for the same square shape and also for the same dimensions) and a complementary symmetrical metamaterial resonator (CSRR) for a square shape with optimized dimensions. The set of two square SRRs of magnetic activity for negative permeability (\(\upmu \) <0) and of the CSRR is etched on the upper face of a chosen substrate. The electrical qualities of our filter are improved by the electromagnetic inter-resonator coupling in the chosen optimum position and also by the coupling to the two microstrip feed lines. The results obtained based on simulations performed by the High-Frequency Structure Simulator (HFSS) commercial software show the impact of electromagnetic coupling between SRRs and the CSRR on our proposed filter. For the DBBPF without the CSRR, the two frequency bands are not so clear. But with the CSRR, the DBBPF filter becomes more selective, having two bandwidths 320 MHz and 280 MHz, respectively.