Reconfigurable ring slot antenna with polarization diversity using pneumatic control

In designing reconfigurable antennas, pneumatic control of solid dielectric slugs offers an alternative to established technologies of reconfigurability, such as PIN diodes and MEMS switches, that require biasing feedlines embedded in the radiating structures. A pneumatically controlled ring slot antenna capable of switching between LP, LHCP, and RHCP is described, in which the dielectric slugs and their enclosing channel are fabricated on a different layer. The positions of the slugs, controlled by the pressure gradient within the channel, determine the polarization state. An axial ratio bandwidth of 5% was measured, which is slightly greater than those of similar antennas with polarization diversity using PIN diodes. The measured performance was found to be similar to existing reconfigurable antennas, demonstrating that a device using pneumatic actuation is a viable alternative.