Double triangular monopole-like antenna with reconfigurable single/dual-wideband circular polarization

A polarization and frequency reconfigurable circularly polarized (CP) antenna is proposed based on a novel bilateral switching mechanism. Two triangular monopole antennas are connected to each other in an L-shaped form by a narrow link to produce a CP operation. In the proposed technique, 4 PIN-diode-based switches are designed with desired insertion loss and isolation, and only 2 DC-voltage controllers. These switches are located on the links and the feed lines to realize a polarization reconfigurable feature including both right-hand CP (RHCP) and left-hand CP (LHCP) modes. Moreover, 2 CP states, a single wideband operation and a dual-band operation, can be supported by this mechanism. In a special performance of the switches, CP reconfigurability can be obtained in a narrow-band mode around 2.45 GHz. Two general simulations are performed based on the simple microstrip links and a diode-circuit model. The measured results exhibit a wide overlapped bandwidth (AR<3 dB and VSWR<2) of 44.4% (1.63-2.56 GHz) with a peak gain of 2.88 dBi in the first state and 5.5% (1.22 approximate to 1.29GHz) and 20.6% (2.12-2.61 GHz) with the peak gains of 0.52 and 3.0 dBi in the second state, respectively. A wide beamwidth is obtained more than 75 degrees. This work is appropriate for L- and S-band CP diversity applications.