Radiation performance improvement for wideband patch antenna by using characteristic mode analysis

A novel method is proposed to achieve radiation performance improvement for patch antennas by using characteristic mode analysis (CMA). In our previous work, a microstrip patch antenna composed of a driven patch and parasitic square patches was presented to realize wideband performance. To improve the radiation performance, the parasitic patches are replaced with split ring resonators (SRRs). Compared with the previous antenna, the unwanted higher-order modes of the proposed antenna are effectively suppressed based on the simulated results of CMA, leading to good radiation performance. Meanwhile, wideband performance is maintained as well. Simulated results indicate that these two antennas share similar wide bandwidth more than 30%. However, the gains at the higher resonant frequency for these two antennas are 10.8 and 11.75 dBi, respectively. Finally, measured results show that the bandwidth of SRR loaded antenna is from 10.5 to 15.3 GHz, and the gain varies from 8 to 11.5 dBi across the operating bandwidth.