Using anisotropic high impedance surfaces for tuning antenna performance

More recently, structures capable of being produced inexpensively and operated in the more commercially viable bands have been proposed. Unfortunately, high impedance (high-Z) surfaces capable of operating at lower frequencies tend to be far more susceptible to fabrication errors because of complex surface patterns. In most cases, standard circuit board manufacturing tolerances are too loose to create such high-Z surfaces to the necessary accuracy. To circumvent these difficulties in fabrication, we propose that adding a small degree of anisotropy to high-Z surfaces can enable compensatory tunability for certain planar antennas located on the surface by simply rotating the antenna. Doing so allows fabrication tolerances to be loosened to those available for large scale, inexpensive fabrication