Analysis, Design, and Measurement of Continuous Frequency-Scanning Polarization-Rotating Antenna

Polarization reconfigurable antennas are useful in certain wireless systems to adapt to different incident polarizations or measurement systems. In this work, we develop an innovative and simple frequency-controlled polarization-rotating antenna. The antenna provides continuous adjustment of the orientation of linear polarization (LP) over a range of 180°, making it suitable for applications such as identifying objects with diverse orientations in sensing and detection systems. We introduce a general model of an LP antenna, in which the orientation of polarization can be controlled with an adjustable phase shift. By substituting the phase shift in the model with one that is frequency dependent, a 180° LP rotation can be attained by sweeping the source frequency across a custom-designed bandwidth. This allows the implementation of an antenna system that can continuously adjust the orientation of LP in response to frequency scanning over a wide operating bandwidth. As demonstrated in a prototype, a 180° polarization scan with a realized gain varying between 7.0 and 9.8 dBi is achieved by sweeping the frequency from 9.6 to 11.65 GHz. The continuously frequency-scanning polarization rotation behavior offers a novel and efficient solution for polarization reconfiguration.