A Low Profile Circularly Polarized Antenna based on Stepped Open-ended Slot Radiator

摘要

A compact wide band and low profile circularly polarized antenna is presented based on stepped open-ended slotline in this paper. The antenna is composed of four open-end-slotted patchs and a feed network. Four open-end-slotted patchs are sequentially rotated and vertically soldered on the ground plane of the feed network, and are excited by a wide band transition from strip-line to slot-line with short pin in antenna element. The CP radiation of the proposed antenna is realized by four output ports of the feed network which transmit four signals that have equal amplitude with quadrature phase difference (0 degrees, 90 degrees, 180 degrees, and 270 degrees). Simulation results are compared with the measurements, and a good agreement is obtained. The measured results show that the proposed antenna can provide broad impedance bandwidth of 73.4% (3.5 GHz-7.56 GHz) (reflection coefficient less than -10 dB), a maximum gain of 4.74 dBi, and a 3-dB axial ratio (AR) bandwidth of about 35.1% (3.65 GHz-5.2 GHz).