Broadband Full-Metal Cavity Slot Antenna Using Mixed Resonant Modes

In this letter, a broadband full-metal cavity slot antenna using mixed resonant modes is proposed. A simple dual-resonance slot antenna is first presented, which is composed of a feeding probe and a metal cavity with a rectangular slot on the top wall. The rectangular slot can produce a resonant-iris mode, while the feeding probe can produce a coaxial-cavity mode. Benefitted by introducing the new coaxial-cavity mode, this antenna can simultaneously achieve wide operating bandwidth and simple antenna structure. To further improve the bandwidth, this dual-mode antenna is combined with a dual-mode cavity resonator operating at TE101cavity mode and resonant-iris mode, thus realizing a quadruple-resonance broadband antenna. The experimental results show that the proposed quadruple-resonance metal cavity slot antenna can achieve 54% bandwidth with stable radiation pattern and high total efficiency over the entire operating band.