Design and fabrication of pneumatically controlled capacitive switches

Series capacitive switches controlled by means of pneumatic pressure are introduced. The switch was incorporated into a microstrip line to demonstrate its viability. The position of a copper-coated dielectric solid slug, confined in a chamber which rests on top of a gap in the microstrip line, dictates the state of operation of the switch. The switch was fabricated and measured using a TRL calibration to remove the effect of the coax-to-microstrip transitions. The simulated insertion loss of the closed switch was below 0.5 dB up to 15 GHz and up to 10 GHz for the fabricated device. The measured isolation of the open switch is better than 15 dB over the entire measured range up to 15 GHz. Successful fabrication and measurement of these switches serves as a proof of concept for implementing this technology in reconfigurable antenna designs.