A Wideband Polarization-Reconfigurable Antenna Based on Fusion of TM10 and Transformed-TM20 Mode

A wideband polarization-reconfigurable microstrip antenna based on a mode-fusion mechanism is proposed. This simple antenna structure consists of a rectangular radiation patch and a ground, both with crossed slots. The slots crossing the ground are connected by eight PIN diodes and four capacitors such that two orthogonal linear-polarization radiation modes can be realized. The radiation patch is slotted such that a transformed TM20 mode is excited, realizing broadside radiation that the traditional TM20 mode is unable to. With fusion of the fundamental TM10 mode and the transformed-TM20 (T-TM20) mode, a wide bandwidth of 30.1% is achieved in two reconfigurable polarizations. The measured results agree well with the simulation results. The total efficiency of the proposed antenna is more than 80.0% over the bandwidth.