Small-Volume Microstrip Patch Antennas Exactly Covering Wi-Fi 6 Bands of 2.4-2.5 GHz and 5.15-5.85 GHz

The sixth generation of wireless fidelity (Wi-Fi 6) spectrums possess two unbalanced bands of 2.4-2.5 GHz (4.1%) and 5.15-5.85 GHz (12.7%). Most of the existing dual-band Wi-Fi 6 patch antennas are with either a superfluous lower or an insufficient higher bandwidth. It remains a challenge to cover these two bands in an exact way. This article addresses the issue of the exact coverage problem of the unbalanced Wi-Fi 6 bands by engineering the TM 0.5,0 and TM 0.5,1 modes of the half-mode patch while maintaining a very small volume. The design guideline follows three steps. First, select proper patch size to make the first two modes resonate at 2.45 and 5.5 GHz using two ports. Second, optimize feeding positions to make both impedance trajectories in the Smith Chart with minimum sizes. Third, use lumped components to make the two resonances with good matching condition. Using the novel matching method, the resultant half-mode patch with a profile of 3 mm ( 0.024 λ L/0.052 λ H) and size of 22.55 ×23.95 mm2 ( 0.18 × 0.19 λ L^{2}/0.39 × 0.41 λ H2) exactly covers the Wi-Fi 6 bands, indicating that the antenna space is taken up fully. As far as the authors know, the proposed antenna is with the smallest volume compared to all the reported Wi-Fi 6 dual-band patch antennas. Moreover, the proposed antenna is with dual-port and aperture sharing properties, which suits the optimal Wi-Fi 6 radio frequency (RF) front-end architecture.