Wideband Patch Antenna With Ground Radiation Mode and Patch Radiation Mode

In this paper, patch antenna structures are studied to simultaneously excite the ground radiation mode and patch radiation mode. Based on the analysis of characteristic current distribution on the ground plane of patch antenna, an exciting method of the ground radiation mode is proposed. Then a dual-mode patch antenna of patch radiation and ground radiation is designed, which can achieve a wideband radiation using two modes resonating at two adjacent frequencies. To improve the radiation efficiency of the ground mode, the electric field distribution of the dual-mode antenna is investigated in detail and the electric field models for two modes are constructed. It is suggested that the additional notches introduced on the ground plane can enhance the resonance component of the ground mode. By this way, the modified patch antenna presents better radiation efficiency over the operating band. The measurement results show that the relative bandwidth of the patch antenna prototype with the notches is about 16.2%, defined by the reflection coefficient less than -10 dB. The proposed dual-mode antennas have the inherent characteristics of weak directivity, for that the antenna application scenarios also are indicated.