2.45 GHz end-loaded dipole backed by a high impedance surface

An end loaded planar open sleeve dipole (ELPOSD) antenna over an electromagnetic band gap (EBG) high impedance surface is presented. An ELPOSD consists of a printed dipole with two parasitic elements (sleeves) along its sides and capacitive loading at the end. This antenna is fed from beneath the ground plane by live vias connected to a microstrip to coplanar strip balun. The EBG structure is based on the Jerusalem Cross geometry and is sandwiched between two 1.27 mm-thick substrate layers, resulting in a total antenna thickness (excluding the feed layer) of ~λ/50. Measured performance of the antenna demonstrates a bandwidth of 30 MHz at 2.45 GHz, with a gain of ~3.5 dB.