A Compact Broadband Water Patch Antenna

A novel compact broadband water dense patch antenna with relatively thick air layer is introduced. The distilled water with high permittivity is located on the top of the low-loss, low-permittivity supporting substrate to provide an electric wall boundary. The dense water patch antenna is excited with cavity mode, reducing the impact of dielectric loss of the water on the antenna efficiency. The designs of loading the distilled water and T-shaped shorting sheet are applied for size reduction. The wide bandwidth is attributed to the coupling L-shaped probe, proper size of the coupled T-shaped shorting sheet, and thick air layer. As a result, the dimensions of the water patch are only 0.146 λ₀ × 0.078 λ₀ × 0.056 λ₀. The proposed antenna has a high radiation up to 70% over the lower frequency band of 4G mobile communication from 690 to 960 MHz. Good agreements are achieved between the measured results and the simulated results.