A new wideband circularly polarized square-slot antenna with parasitic elements

ABSTRACT A novel broadband circularly polarized square-slot antenna with parasitic elements is presented in this article. The proposed antenna with dimensions of 77.6 × 77.6 × 1.6 mm3 is composed of a L-shaped strip, a pair of rectangular slots, a L-shaped branch, and an inverted L-shaped feeding line. First, a pair of rectangular slots are used to excite an impedance resonance point that appears near 4.8 GHz and improve the axial ratio bandwidth (ARBW). Second, a L-shaped strip etched into the square-slot ground plane is used to enhance the ARBW. Third, a L-shaped branch is inserted into the inverted L-shaped feeding line to improve the impedance matching at high frequencies. At a result, the multiple circularly polarized (CP) resonant points could be excited by using these slot and strips as perturbation elements to alter the surface current distribution of the antenna. To demonstrate the design rationality, a designed antenna model is simulated, manufactured, and measured. The tested results show the proposed antenna has a wider −10-dB impedance bandwidth from 2.6 to 6.6 GHz (86.9%) and a broad 3-dB ARBW from 2.35 to 5.80 GHz (84.7%). In addition, the measured peak gain of the antenna is 4.8 dBi. The presented antenna has a potential application value in C band wireless communication.