Small Size, High Gain and High F/B Ratio Patch Antenna Arranging Parasitic Element on the Back

A small size patch antenna with high gain and high front-to-back (F/B) ratio has been newly developed. The antenna consists of two elements, that is, RF exiting element arranging on the front side and parasitic one on the back. The latter is terminated by the reactance. The antenna is as small as 80x80x8 mm in size and shows the gain and F/B ratio of 6 dBi and 15 dB at 950 MHz band, respectively. The obtained results are about 2 dB and 10 dB higher in gain and F/B ratio, respectively as compared with the conventional patch antenna. The size dependence of the performance has been investigated for antenna design by the simulation. The result shows that decreasing the element width with sacrificing the increase of thickness is found to be effective for minimizing the antenna volume.