Design of microstrip patch antennas with improved low-elevation gain for CRPA applications

This article proposes the design of microstrip patch antennas to improve low-elevation gain for controlled reception pattern antenna (CRPA) applications. The proposed antenna consists of a main resonant patch and a subpatch that are electromagnetically coupled with each other to operate as a two-element array whose bore-sight direction points toward low-elevation angles. The array factor is then enhanced by inserting a ceramic substrate with a high dielectric constant to maximize the electrical distance between the patches. As a result, the average gain at =75 degrees is enhanced by 1.2 dB, which demonstrates that the proposed antenna is suitable to be used for the individual elements of CRPA arrays with the improved radiation gain at low-elevation angles