A novel low profile high-gain UHF antenna using High-Impedance Surfaces

A High-Impedance Surfaces (HIS) analysis is presented to study the feasibility of these elements to be used in the novel design of low-profile planar antennas for UHF applications. The proposed 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 backradiation, 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 to a conventional antenna with PEC ground plane are presented.