A Structurally Simple Patch Filtenna Based on Dual-Mode Triple-Line Resonator

This letter proposes a filtenna based on the dual-mode triple-line resonator (TLR) structure. Due to the dual modes' unique current distributions, their eigenmode frequencies can be independently adjusted. As a fundamental filtering structure, the radiation null (RN) of the TLR patch can be flexibly controlled. Moreover, with shorted pins loading, the dual RNs flanking passband can be easily achieved while maintaining a compact structure. To enhance the high-frequency suppression level without disrupting the existing passband, a specific non-standard coupling matrix is synthesized. A U-shaped slot and double non-resonating stubs are loaded to provide an additional RN. It demonstrates the extensibility of the TLR and its compatibility with other popular filtering schemes. The final filtenna exhibits a fractional bandwidth (FBW) of 10.56%, a peak realized gain of 7.74 dBi, 3 RNs, and suppression levels of 20.97 dB and 18.42 dB. The proposed patch was fabricated and tested for validation. It offers advantages such as a simple structure, wide bandwidth, and high selectivity. These features fulfill the requirements for the new 5.925-7.125 GHz communication band, which applies to Wi-Fi 6E/7 and future 6G technology.