Monopole Antenna with Dual-Band and Dual-Sense of Reconfigurable Circular Polarization

A simple design of a dual-sense circularly polarized antenna for dual-band application is proposed here. The design consists of a microstrip line fed rhombus shaped ring monopole, a modified ground plane, only two PIN diodes as switching elements and biasing circuit. Dual-sense of polarization in two different bands can be reconfigured by controlling the ON - OFF states of those PIN diodes. To validate the simulated results, a prototype of the antenna is fabricated and measured. Measured results show that a wide overlapped bandwidth (by considering vertical bar S-11 vertical bar <= -10 dB and axial ratio <= 3 dB) of > 68.5% in lower band and > 8.2% in upper band are obtained from the fabricated prototype.