A Directive Antenna Based on Conducting Disks for Detecting Unintentional EM Emissions at Large Distances

This paper proposes a novel high-gain planar antenna design that consists of conducting metallic disks suspended on air and operates at 1 GHz. The antenna is designed for receiving the unintentional electromagnetic emanations generated by one or multiple embedded, “smart” electronic systems. The antenna consists of two layers of slotted conducting metal disks suspended on air and placed above the ground plane using teflon screws. The circular disks are designed to operate in higher order ${TM}_{12}$ mode. The screws’ location is the electric field nulls along the disk radius. The upper layer is $2 \times 2$ array of slotted circular disks electromagnetically coupled by the lower identical disk which is fed directly by a single coaxial feed. The complete fabrication of the antenna is done using aluminum metal sheets and involves no use of the dielectric substrate. The antenna has a peak gain of 19 dBi with impedance bandwidth ( $S_{11}\le -6$ dB) of 6.7%. The simple and cost-effective design can be easily scaled to higher frequencies.