A cognitive compensation mechanism for deformable antennas

This work presents the design, theory, and measurement of a linearly polarized microstrip patch antenna with a substrate-integrated compensation mechanism to mitigate the detuning effects from a physical deformation (e.g., bending and twisting). In particular, we investigate the ability of an antenna to maintain its impedance bandwidth as it bends sharply through the center (from flat up to 90° pivoted about the ground plane). Compensation for this bending occurs through the displacement of electromagnetically functionalized colloidal dispersions (EFCDs) in a substrate-embedded capillary. By replacing a high permittivity EFCD with a low permittivity EFCD during bending this provides a net length reduction to oppose the length extension (stretching) from the bending action. Stability of the 2:1 VSWR (matched impedance) bandwidth has been examined numerically across the entire range of bending, and examined experimentally using fixed-bend patch antennas on 4 mm thick isiocane foam substrates (one flat patch and one patch bent to 90°) to demonstrate this concept. A deformable patch antenna fabricated on a silicone substrate with conductive elastomers has also been examined and trends between simulated and measured results are in good agreement.

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