DOI: 10.1109/TMTT.2025.3532037   IEEEXplore: https://ieeexplore.ieee.org/document/10856682    

Input-reflectionless filter/filtenna on substrate-integrated-waveguide (SIW) technology based on complementary-diplexer topologies

10 GHz proof of concept

The design methodology begins with a synthesized coupling matrix, develops a dimensional physical design from the couplings, and replaces the last resonator of the bandpass channel with a radiator for an absorptive SIW-based RF filter-antenna, or filtenna. A third-order bandpass filter and filtenna, a second-order diplexer, and a dual-band filtenna, all desigfned with this methodology, are demonstrated in this article.

This novel class of RF filtenna device finds potential application in almost any communications device where reduced size and loss are key performance requirements.

47.5 R/O (ratio of reflectionless range to operational BW) for a single-layer SIW filter/diplexer, 18.06 R/O for a double-layer SIW filter/diplexer far exceeds performance of devices derived by other design methodologies. 27.27 R/G (ratio of reflectionless and 3dB gain BWs) for a single slot reflectionless antenna far exceeds performance of reported single-band reflectionless antennas; 11.6 R/G for a dual-slot reflectionless antenna. No dual-band input reflectionless antenna has been previously reported to the authors' knowledge.