Dual-Band Dual-Mode Patch Antenna with High-Gain and Wide-Beam Radiations in Two Respective Bands

In this paper, a novel dual-band dual-mode (DBDM) patch antenna is proposed with flexible radiation coverage and a simple structure. Distinct radiation properties with high-gain in the lower band and wide-beam in the upper band could be attained under a small frequency ratio and a single element. The working principle of the wide-beam radiation is, for the first time, proposed and theoretically analyzed based on the electric current calculation, providing a good insightful understanding of the radiation of the inverse currents. The high-gain radiation in the lower band is realized by introducing the shunt inductive effect while maintaining a negligible influence on the upper band. In terms of realization, a pair of stubs and shorting pins are properly loaded on a square patch to achieve the conditions required in the theoretical analysis. It indicates that the proposed method could be easily achieved with the simple structure of a single layer and a single element. Additionally, further discussion on the size reduction of the patch is provided with good cross-polarization. Two prototypes are finally designed, fabricated, and tested. The simulated and measured results exhibit good agreement with each other, certifying the validity of the proposed method. All these attractive merits, such as flexible coverage with high-gain and wide-beam radiations, simple structure with a single element, small achievable frequency ratio, and low profile, demonstrate that the proposed antenna could be a good potential candidate in the modern wireless systems.