Dual Linearly Polarized Microstrip Antenna Using a Slot-Loaded TM₅₀ Mode

We present a high-gain, low-profile dual-polarized microstrip antenna operating in the hybridized higher order mode. The proposed antenna consists of a slot-loaded cross-shaped patch, which can be considered as orthogonally polarized radiating elements operated in the TM₅₀ mode. Moreover, the four loaded slots can effectively excite the in-phase TM₁₀ mode such that the superposition of both modes can lead to gain enhancement in the broadside direction, with suppressed sidelobes. The proposed antenna requires only a single-dielectric layer and a simple feeding method, while exhibiting good isolation between the two polarizations. We have developed a prototype, which has a total size of only 1.65 λ₀ × 1.65 λ₀ × 0.04 λ₀ (λ₀ is the free-space wavelength at the center frequency) and a measured maximum gain of 10.9 dBi. This dual-polarized microstrip antenna with the advantages of high gain, low profile, low cost, and good isolation, is envisioned to benefit many multiple-input, multiple-output and the fifth generation (5G) communication systems.