Miniaturized SIW Wideband BPF Based on Folded Ring and Meander Line Slot for Wireless Applications

A miniaturized wideband bandpass filter (BPF) substrate integrated waveguide (SIW) has been proposed in this paper for the operation in X-band applications. The design of the suggested filter is carried out by etching a complementary folded ring resonator (CFRR) cell embedded with a meander line slot on the top layer of the structure. The filter performance has been evaluated of the proposed filter have been carried out using the Microwave Studio Suite, CST electromagnetic simulator. A parametric study has been conducted to explore the influence the various filter elements on its performance. The results show that the application of the (CFRR) cells makes the filter to possess a more compact size and a broader bandwidth. The SIW cavity dimensions are 13 × 9.4 mm
²
while the overall filter dimensions are 18 × 10 mm
²
using a substrate having a relative dielectric constant of 6 and thickness of 0.508 mm. The realized results demonstrate a return loss of less than -45 dB and insertion loss of about -0.5 dB with a fractional bandwidth of about 45% centered at 8.56 GHz. These features offered by the proposed filter make it more suitable for use in the design of modern microwave and millimeter-wave circuits.