DUAL FREQUENCY CIRCULARLY POLARIZED CROSS-SHAPED SLOTTED PATCH ANTENNA WITH A SMALL FREQUENCY RATIO

摘要

A compact novel probe-feed single-layer annular ring, dual-frequency circularly polarized (CP) microstrip antenna is assessed numerically and experimentally in this communication. The antenna characterizes a small frequency ratio with good impedance bandwidth. The dual band operations are realized using two circular patches with one annular ring slot and exact feed position. In addition, a cross shaped slot is placed in the patch to achieve circular polarization. The antenna geometry structure is simulated using a commercially available electromagnetic solver high frequency structural simulator. The simulated and measured results, costly match within the operating bandwidth. The experimental results depict a 10-dB return loss bandwidth of 15 MHz (2.415-2.430 GHz) for the lower band and 15 MHz (2.895-2.910 GHz) for the upper band, respectively. The measured 3-dB axial ratio bandwidth is 0.826% (2.410-2.430 GHz) for the lower band and 0.862% (2.880-2.905 GHz) for the upper band. The frequency ratio of the upper and lower band is 1.19. The overall antenna size is 0.363 λ_0×0.363 λ_0× 0.013 λ_0 at 2.42 GHz. Details of the obtained dual band CP performances are also presented and discussed.