Fluidically Reconfigurable Multifunctional Frequency-Selective Surface With Miniaturization Characteristic

This paper presents a multifunctional reconfigurable frequency-selective surface (FSS) based on liquid-metal-filled microchannels engraved in an elastomeric substrate. The proposed FSS comprises two layers of periodic meandered patterns encased within the opposite sides of a dielectric, where the layers are arranged in orthogonal polarization with independent control of reconfigurability. The novelty of the design lies in its switching characteristic between four different working states (dual-polarized all pass, single-polarized low pass, single-polarized bandpass, and dual-polarized bandpass) with the injection of a liquid metal in the top and bottom microchannels. Moreover, the design exhibits miniaturization performance during one of the states (exhibiting dual-polarized bandpass response at 1.58 GHz) corresponding to the unit cell dimensions of 0.052 lambda(0) x 0.052 lambda(0). The equivalent circuit models and parametric variations are extensively analyzed for understanding the design principles. Because any liquid-metal-based reconfigurable FSS structure has not been reported earlier, a detailed description of the fabrication and measurement procedure are presented in this paper. The experimental validation of the fabricated prototype also confirms the potential use of microfluidic technology-based reconfigurable structures in future.