Body armour with integral high impedance surface

This paper describes the performance of high impedance surfaces (HIS) integrated into body armour equipment. A protective insert made of Aramid material and a metallic woven layer is used as the dielectric material with a metallic ground plane of the HIS. The frequency selective layer added to create the high impedance surface consists of a 15×15 array of interwoven spiral elements capable of reducing size of the cell by over 98% compare to the typical square patch element. The HIS has been designed to operate at around the 400MHz band TETRA employed by the police and emergency services in Europe. The HIS is able to improve the matching of the antenna by over 7dB compared to the antenna mounted directly on the armour vest. The paper includes simulations and experiments.