CAD and optimization of circularly-polarized microstrip arrays

Circularly-polarized (CP) antennas are often used in deep space or satellite communications. Depending on the application, the operating frequency ranges from S-band to Ka-band. To yield a high gain, it is important to minimize mismatch in the feed network. The design of each array element is also crucial in yielding a good tradeoff between reflection loss and axial ratio. Analysis at the subarray level is often required to ensure a good design. The authors examine the design of circularly-polarized arrays in the S-band and the Ka-band at the element as well as the subarray level. They demonstrate how the design process can be enhanced by the use of a powerful computer-aided design (CAD) software tool for designing microstrip antennas.