Differentially-Fed Circular Patch Antenna under Dual High-order Modes for Enhanced Bandwidth and Stable High Gain

A differentially-fed circular patch antenna under dual high-order modes for enhanced bandwidth and stable high gain is proposed in this paper. The current distribution of TM
₃₁
mode is reconstructed by loading two open slots at the edge of patch, by which the broadside radiation of TM
₃₁
mode is substantially increased. By loading an additional slot in patch's center, the current of TM
₁₂
mode is reshaped to be more in-phase, and so the sidelobe radiation is dramatically reduced. The resonant frequencies of TM
₃₁
and TM
₁₂
modes are then reallocated and get close to each other due to the loading of slots and shorting pins, which finally contributes to an enhanced bandwidth of 12.9%. Moreover, the antenna produces high gain up to 13.7 dBi, while the beamwidth and gain level are kept stable in band.