Abstract: A self-contained system containing an antenna, a circuit board, and a power source. The antenna consists of two loop elements mounted perpendicular to each other on a circular metal plate that acts both as part of the radiating system and as a shield between the circuitry and the radiator. The circuit board includes a transmitter, a receiver, and other circuitry for storing information and executing software. The antenna has a high gain, is omnidirectional in two orthogonal polarizations, and has a high degree of isolation between the two loop elements. To achieve omnidirectionality, in one mode, the antenna operates by using each loop element in a time-sequence of brief on/off states. In another mode, the transceiver uses both loop elements simultaneously with the signals on the two loop elements in phase quadrature.

Abstract: An efficient electrically small loop antenna includes a radiation device, an impedance matching network, and a connector that interfaces to associated electronic circuitry. The radiation device includes a conductive planar base element extending in a base plane and a conductive loop connected to the planar base element. The loop connects to the base element so that the electrical current for the antenna flows through both the conductive loop and the planar base element. The impedance matching network matches the radiation device to the associated electronic circuitry. The matching network is integrated into the planar base and is connected to both the conductive loop and the base element so that the electric current supplied to the antenna is conducted through both the base element and the conductive loop.