Two-layer electromagnetically coupled rectangular patch antenna

The authors report an experimental study of a rectangular electromagnetically coupled patch antenna excited in the TM/sub 01/ mode. The major finding is that, depending on the spacing s, the characteristics of the antenna can be separated into three regions. Region 1 is associated with bandwidths exceeding 10%, region 2 has abnormal radiation patterns, and region 3 is associated with narrow beamwidths. The values of s separating these regions depend on the dielectric material between the two-layers. A high-gain region is found both when the dielectric material separating the two layers is air and when it is teflon. This region begins at s=0.3 lambda for air and at s=0.21 lambda for teflon, with antenna gains of 9 and 11 dB, respectively, for the two cases. It can be utilized in applications where narrow bandwidths is not a disadvantage.<>