Large frequency tuning of a millimeter-wave antenna using dielectric liquids in integrated micro-channels

In this work, investigation has been made of a planar millimeter wave antenna on microfluidic channels which allow a very large resonance frequency tuning up to 51% (from 16.8 to 28.4 GHz). A microstrip antenna lays over a 12 mil (300 μm) thick liquid crystal polymer (LCP) substrate in which two micro-channels are drilled to be filled with different dielectric liquids (water, ethanol, methanol, acetone). The two channels are strategically placed under the radiating edges of the patch antenna where the electric field is the strongest. Thus, by changing the liquid in the channels, the equivalent permittivity of the multilayer structure is locally modified and the resonant frequency of the antenna is strongly tuned.