6/5/2015 SIW Filter Screens Narrow Bandwidth http://mwrf.com/print/passivecomponents/siwfilterscreensnarrowbandwidth 1/7 print | close SIW Filter Screens Narrow Bandwidth Ali Frotanpour, Ali Foudazi, and Leila Mohammadi Thu, 20121206 21:00 This dualmode, substrateintegratedwaveguide (SIW) filter offers an asymmetric response and outstanding return loss at a center frequency of 11.3 GHz. Filters employing substrateintegratedwaveguide (SIW) technology can achieve high selectivity with low passband insertion loss. By way of demonstration, a narrowband, secondorder, dualmode SIW filter was designed for use at 11.3 GHz. Following computer software simulations, the filter was fabricated and found to have high rejection and low passband insertion loss around the center frequency. The filter includes a square SIW cavity, two coupling metalized vias (CMVs), and input/output microstrip lines. Two CMVs in the corner of the cavity provide coupling between degenerate modes. Pseudoelliptic filters with finite transmission zeros are not new, but have been widely studied in the literature. 13 The main challenge in developing these pseudoelliptic filters is to achieve an asymmetric response. 2,3 Dualmode filters that support crosscoupled network can be designed to satisfy the asymmetric response. Filters based on SIW technology are useful in microwave integrated circuits (MICs), for a wide range of applications in communications, for suppressing unwanted responses and interference. Learning to implement SIW technology on MIC printedcircuit boards can be instructive, as well as add a great deal of value to both active and passive microwave circuits. For example, SIW technology has been widely used for a number of different types of microwave filters. 49 To demonstrate the use of the technology, a narrowband dualmode secondorder filter based on SIW technology with an asymmetric response was designed and fabricated. The filter employs two CMVs for coupling between degenerate modes. The filter achieves two righthanded transmission zeros as a result of sourceload coupling and the CMV position.