Non-Contact Coupling between Antenna and Circuit Front-Ends

Two simple methods for non contact coupling of differential signals to an antenna are presented. In the proximity coupling technique, a differential signal generates voltage maxima on either side of a microstrip gap under an antenna while in the aperture coupling technique, a current maxima is generated and energy is electromagnetically coupled via an aperture under the antenna. Both techniques effectively merge the front end balun or power combiner/divider into the antenna feed. Both feeding methods have been successfully applied to the design of simple passive microstrip antennas and active integrated antennas (AIA)s. These techniques are also applicable to traditional compact antennas such as the planar inverted F antenna (PIFA), H-shaped microstrip antennas and meandered dipole antennas. Simulated and measured results will validate the applicability of the feeding techniques to these alternative antennas.