High-gain low-cost microstrip antennas and arrays based on FR4 epoxy

In this work, two previously reported low-cost design techniques for high-gain microstrip antennas are compared based on detailed parameter study. Both of these methods exploit a combination of a spacer and a layer of FR4 epoxy. The distinguishing feature of the said methods is the position of the metallization. A parameter study is performed on the thickness of the FR4 layer and its effect on the antenna gain, efficiency and pattern symmetry is reported. Capability of these methods is designing high-gain arrays is studied and specific design examples are provided. It is shown that the first method has superior performance in the sense of gain and efficiency. Especially, the first method supersedes the second one for high-gain arrays. As well, it is shown that the first method is a pure microstrip alternative to another previously reported technique wherein a CNC milled waveguide structure is exploited as the feed network.