Compact tri-band antenna with integrated slot-strip filtering for Wi-Fi 7 multi-link operation

This paper presents a low-cost, compact tri-band antenna with an integrated filtering function, realized using a dual-PCB architecture for Wi-Fi 7 Access Point (AP) applications. The first PCB implements a dual-band array of two dipoles covering the 2.4 GHz and U-NII-1/2A [5.17-5.33 GHz] bands, the second PCB integrates a single-band array of three dipoles operating in the U-NII-3 [5.735-5.835 GHz] band. Filtering features are embedded in the antenna structure to suppress unwanted signals: the dual-band array rejects the U-NII-3 band, whereas the single-band array suppresses the U-NII-1/2A band through slots and strips. Decoupling rings provide strong port isolation, with measured S21 reaching −33 dB. The measured gains are 2.37 dBi, 3.23 dBi, and 3.21 dBi at 2.4 GHz, 5.2 GHz, and 5.78 GHz, respectively, while the radiation efficiency reaches about 63%. Its compact size makes it suitable for Multi-Link Operation (MLO), enabling reliable Wi-Fi performance in multi-AP/multi-user FTTR deployments.