Circularly polarized patch antenna with simultaneously wide frequency tuning range and high gain performance

Abstract

A tunable circularly polarized square patch antenna with parasitic elements is designed for a wide frequency tuning range and high gain characteristics. The proposed antenna is constructed by one main patch and four semi-elliptic parasitic units. By loading four varactor diodes and adjusting their capacitance values, the tunable feature is performed to reallocate the corresponding working frequency. Moreover, the diagonal corners of the antenna are cut and loaded with varactor diodes, which provide the appropriate perturbation between the two orthogonality modes of the antenna, so as to ensure the circular polarization characteristic in the entire operating tuning band. The experimental results demonstrate that the reflection coefficient and axial ratio are less than À13 dB and 3 dB, respectively. The proposed antenna features a relatively wide continuously tuning range of 24% within 1.9-2.3 GHz and a stable gain of over 7 dBi with a radiation efficiency of above 85%.

An ultra‐wideband dual circularly polarized slot antenna with high isolation

“…Circularly polarized (CP) antennas have enjoyed prominent applications in many systems for the better performance of receiving the incident waves with any polarization and reducing multipath interferences. [1][2][3][4] Meanwhile, ultra-wideband (UWB) antennas with an impedance bandwidth (IBW) of more than 100% have drawn extensive attention due to the increasing demands for higher data rates and greater capacity in wireless systems. 5 Additionally, port-port isolation is a critical consideration in the design of antennas.…”