Null Frequency Scanning Antenna Based on Asymmetric Phase Transforming of Spoof Surface Plasmon Polaritons (SSPPs)

A null frequency scanning antenna is proposed based on the asymmetric spoof surface plasmon polaritons (SSPPs) in this paper. Dispersion property of the SSPP mode is determined by the sub-wavelength configurations, and phase constants of electromagnetic waves in SSPP mode vary nonlinearly with the frequency change. Therefore, two SSPP radiators with asymmetric phase transforming could realize frequency scanning in the boresight for either null or main lobe when magnitudes of radiated fields are the same and phase difference between two radiators is even or odd multiple of 180°. A prototype antenna is designed and simulated from 5.99 GHz to 6.44 GHz, and angular range of null scanning is from -20° to 28° is obtained with null depth over 20 dB. The proposed antenna has potential in suppressing interference and realizing frequency scanning monopulse for direction detection and locating.