A Novel Miniaturized Dual-Band Substrate Integrated Waveguide Filter Using Metamaterial Unit-Cells with High Selectivity

In this paper, a novel miniaturized dual-band (DB) substrate integrated waveguide (SIW) filter using metamaterial unit-cells with high selectivity is proposed. The working principle of the introduced configuration is based on the theory of evanescent-mode propagation. Two passbands which are propagating below the SIW cut-off frequency have been generated separately by etching two different types of metamaterial unit-cells on the SIW surface. Because the central frequencies of each unit-cells are different, two different passbands for WiMAX and WLAN applications have been achieved. The resonance frequencies of each unit-cells can be arbitrarily controlled. Consequently, the center frequencies of the designed unit-cells could be independently tuned by resizing the dimensions of each unit-cells. To design of the proposed DB SIW BPF with miniaturized dimension, three different techniques have been used which are the evanescent mode propagation technique, the fractal technique and the meander technique. To demonstrate and verify the novel property of the proposed DB SIW filters, the proposed one- and two-stage filters are fabricated and measured. The measured results are in good agreement with the simulated ones. The results confirmation that a miniaturization about 42% has been obtained. The whole size of the presented DB SIW BPF is only 0.19 λ_g × 0.07 λ_g.