Recent Development on Circularly-Polarized Self-oscillating Active-Integrated Antennas and Its Measuring System

This paper briefly reviews the recent development on self-oscillating circularly-polarized active integrated antennas (CPAIAs), including the advance in antenna design as well as the advance in measuring facilities. CPAIA is a rare topic drawn unreasonably little attention in the literature. We believe it is most likely due to the lack of an easy and low-cost measuring facility for experimental validation, particularly the axial ratio. Recently, we tackle this issue and develop a low-cost polarization sensing system. With the powerful portable equipment, CPAIA designs are no longer a difficult task and a few examples are given in this discussion.