Embroidered Conductive Fibers on Polymer Composite for Conformal Antennas

We provide a novel class of conformal antennas based on embroidered conductive metal-polymer fibers (E-fiber) on polymer-ceramic composites. This new technology offers attractive mechanical and RF performance when compared to traditional flat and rigid circuits and antennas. The proposed E-fiber components are consisted of high strength and flexible polymer fiber cores and conductive metallic coatings. They were fabricated using automatic embroidery process, followed by assembly with polydimethylsiloxane and rare-earth titanate ceramic composites. Such composite substrates were tape-casted, and capable of providing tunable dielectric constant from 3 to 12 with a low tanδ <; 10^-2 up to GHz frequencies. Basic RF prototypes, such as transmission lines (TL), patch antennas, and antenna arrays were fabricated for experimental evaluation. Measurement of the prototypes were conducted and compared to their copper counterparts. The RF characteristics of the E-fiber TLs exhibited an insertion loss of only 0.03 dB/cm higher than copper TLs up to 4 GHz . Also, the E-fiber patch antenna and antenna array exhibited 0.3 dB and 0.6 dB lower gains, respectively, than their copper counterparts. When applied onto a cylindrical surface, both the E-fiber patch antenna and antenna array only suffered 1 dB loss in realized gain, which is quite remarkable when compared with traditional antennas.