Design of a compact low profile high-gain UHF antenna using High-Impedance Surfaces

A low-profile high-gain antenna for UHF applications is presented in this paper, which is based on the use of High-Impedance Surfaces (HIS). The proposed design is an improvement of the structure presented in [1]. This design is based on a wideband monopole antenna in close proximity to an artificial ground plane, composed of an array of square metal loops at the top and a ground plane at the bottom, without grounded vias. Low-cost substrates are employed in the design, rigid PVC for the antenna, and foamed PVC for the artificial ground plane. PVC substrate is ecologic, recyclable, long lasting and cheap, what makes it desirable for this application. The advantages of using a HIS structure as a reflecting surface are the reduction of back-radiation, the increase of the antenna gain, the broadening of bandwidth, and the mitigation of the effects of parasitic surface waves. Details of the proposed antenna design are described, and simulation results together with a comparison with the previous design [1] and with a conventional antenna with PEC ground plane are presented.