A Compact Wide-Band Circularly-Polarized Antenna for Radar Applications in X-Band

This paper presents a compact, singly-fed, circularly polarized microstrip patch antenna designed for operation in the X-band. The proposed structure consists of a central disc-shaped radiating element surrounded by multiple parasitic patches, arranged with specific angular displacements to enable broadband circular polarization through sequential rotation. The antenna is implemented on a low-loss substrate to ensure high efficiency and mechanical stability. Simulation results demonstrate a peak gain of approximately 9 dB, a reflection loss above 10 dB across the operational bandwidth, and a 3-dB axial ratio bandwidth covering a significant portion of the X-band. Owing to its compact footprint, broadband polarization performance, and single-feed simplicity, the antenna is a promising candidate for radar sensing and satellite communication systems.