A Millimeter-Wave Inflatable Frequency-Agile Elastomeric Antenna

This letter reports a millimeter-wave frequency-agile microstrip antenna printed on an ultrasoft elastomeric polydimethylsiloxane (PDMS) substrate. The microstrip patch antenna is supported by a PDMS membrane suspended over an air cavity. The distance H between the patch and the ground plane, and thus the resonant frequency of the antenna, are tuned using pneumatic actuation, taking advantage of the extreme softness of the PDMS membrane. A continuous frequency shift varying from 55.35 to 51 GHz (≈8%) has been obtained for a tuning range of H between 200 and 575 μm. In all configurations, the antenna remains matched and its radiation characteristics are very satisfactory.