Near-Field Reception of Dipole Sources Using a Dual-Loaded Loop

The dual-loaded loop is a two-port antenna configured as two half-loops. Its advantage is the ability to sense two field components instead of the single component of a single-port loop. In this study, the theory of the dual-loaded loop is extended to cases for sensing arbitrarily located electric and magnetic dipole sources. New general expressions are presented for the tangential electric field on a loop resulting from electric and magnetic dipole sources. From these field expressions, closed-form approximations for the currents at the ports are obtained. The approximations are shown to be very accurate through simulation, but can degrade when the separation distance between the dipole source and loop is small. The worst discrepancy occurs when an electric dipole is close to and aligned with one of the ports. These expressions provide a benchmark for checking numerical and physical results for this class of sensor.