A Wideband Dual-Polarized L-Probe Antenna Array With Hollow Structure and Modified Ground Plane for Isolation Enhancement

A two-element wideband dual-polarized L-probe antenna array with hollow structure is presented in this letter. The hollow structure is applied to offer space for hosting other antennas (e.g., the concept of shared-aperture antenna). Each radiating element is designed with a compact size of 51 mm × 51 mm × 24.5 mm (0.374λ₀ × 0.374λ₀ × 0.18λ₀ at 2.2 GHz) and has a hollow volume of 31 mm × 31 mm × 24.5 mm. With a slotted square ring patch and unique L-probes, the antenna element exhibits a fairly large fractional bandwidth of 45%, ranging from 1.71 to 2.69 GHz. Moreover, a narrow slot and T-shaped metallic structures on the ground plane are introduced to increase the input-port isolation of the proposed antenna array to 26 dB across the entire operating bandwidth. The experimental results indicate that the antenna array has an average realized gain of 10.5 dBi, which correlates well with the simulations.