Investigation of Designs for Tuning of Mutual Coupling and Operating Frequency in High-Power Slot Antenna Arrays

Abstract

Today's congested frequency spectrum calls for frequency agile arrays and antennas that can avoid the interference of the myriad of RF sources, from satellites to amateur radio, that take up the same bandwidths. Previous work has been done developing tunable slot antennas for this purpose using varactor tuning methods, but a high power tunable slot array has not yet been developed. This thesis presents work aimed at enabling the creation of this high-power tunable slot array. The development of a miniaturized coplanar waveguide to slotline transition and the simulation of several tunable antenna designs are intended to enable frequency tuning in the array at the element level. The transition is based off of previously developed coplanar waveguide to slotline transitions, but will also be miniaturized to achieve easier implementation into the tunable slot array. This transition will also be used to investigate the effects of different loading mechanisms on the slots, based on a previous tunable slot design. The mutual coupling behavior of a two-element tunable slot array is investigated and a method of tuning the mutual coupling between these tunable slots is developed. From there, a transmission line model of this coupling mechanism is created to aid in further understanding of the design and achieve better understanding of the process of mutual coupling in tunable slot arrays.