Comparative Studies on Wave Guide Open Slot Radiator, H-Plane T-Junction Radiator

Abstract

In defence radar applications, slotted waveguides have excellent, predictable and replicable antenna parameters, when their mechanical manufacturing tolerances defined accurately and controlled. Open slot radiators in the narrow wall of rectangular waveguides are popularly used in several radar applications. Slots used are either longitudinal or inclined depending on the desired polarizations. The longitudinal slots are used for the generation of vertical polarized fields and vertical slots are used for horizontally polarized fields. Sometimes both polarizations are required in succession in defence radar applications. However when longitudinal inclined slots are coupled to a T-arm forming H-plane T-junction, they produce only vertically polarized fields. In this case it is possible to have more parameters for the design of the arrays. At the same time above two types of radiators exhibit different characteristics. In the view of this fact, intensive investigations are made, to bring out and consolidate their comparative characteristics. The admittance parameters, coupling and VSWR are numerically computed using the concept of TE, TM, hybrid and self-reaction concepts.