C-Slotted Patch Filter Antenna with Triple Notches for Enhanced Wi-Fi Performance

This paper presents a low-cost passive patch antenna with filtering capabilities for Wi-Fi applications. The antenna achieves a realized gain of over 5 dBi across all channels in the 5 GHz band. It incorporates a three-pole rejection mechanism with etched C-shaped slots on the same patch radiator. The resulting filter antenna demonstrates radiation nulls and effective band rejections in coexisting Wi-Fi bands, significantly reducing interference. Specifically, a gain reduction of at least 20 dB is achieved at critical coexisting Wi-Fi frequencies: 4.9 GHz (closest 5G licensed band), 5.4 GHz (U-NII-2B), and 5.9 GHz (CV2X).