Capacitor-loaded circularly polarized annular-ring slotted microstrip patch antenna

摘要

This paper studies a simple and novel annular-ring slotted microstrip patch antenna loaded by a surface mount chip capacitor for circularly polarized (CP) radiation. By connecting the capacitor with a proper value across the annular-ring slot at an appropriate position, the fundamental resonant mode of the microstrip patch antenna can be degenerated into two orthogonal modes with equal amplitude and quadrature phase. Hence, CP radiation can be obtained. An antenna prototype was fabricated and measured. The simulation and measurement results validate that the proposed antenna has excellent CP characteristics at the resonant frequency.