Design of very simple frequency and polarisation reconfigurable antenna with finite ground structure

A frequency and polarisation reconfigurable printed monopole antenna using switching PIN diodes is presented. This antenna is made up of a printed monopole, two switching circuits and a reflector. By controlling the on-off states of these two switching circuits on the finite ground plane, a frequency and polarisation reconfigurable antenna is achieved. To verify this design, this antenna is fabricated and measured. The measured results show that this antenna has four states. These states are: state 1, 2.02–2.56 GHz (23.6%); state 2, 2.32–2.95 GHz (23.9%); state 3, 1.92–2.70 GHz (33.8%); state 4, 1.88–2.67 GHz (34.7%). In states 1 and 2, this antenna radiates linearly polarised wave as a traditional printed monopole. In states 3 and 4, this antenna radiates left-hand circularly polarised wave and right-hand circularly polarised wave, respectively.