On the study of passive and active slotline ring antennas

The design and measurement of the passive and active slotline ring antennas are discussed. A simple transmission line method is used to predict the resonant frequency of the slotline ring antenna. Two feed methods for the passive slotline ring antenna are described. A new type of FET active slotline ring antenna is also presented. The measured H-field radiation patterns of the passive and active slotline ring antennas showed that the active antenna had improved copolar pattern and crosspolar level. This active radiating element offers a simple, lightweight, low-cost, small, reproducible, and truly planar active source for quasi-optical power combiners and mixers. The circuit is also amenable to monolithic circuit integration for mass production.<>