Ferrite excited slots with controllable amplitude and phase

This paper describes waveguide slot elements whose radiating characteristics can be electronically varied, both in amplitude and phase. It is well known that a normally nonradiating longitudinal slot in the broadwall of rectangular wave guide can be caused to radiate by discontinuities judiciously placed near the slot and within the waveguide. If the characteristics of the discontinuities (stubs, irises, etc. ) can be varied by external means, the control of slot radiation is facilitated. The use of various ferrite discontinuities are discussed and shown to enable either variable amplitude of radiation or both variable amplitude and variable phase of radiation. The controlling mechanism is a d-c magnetic field provided by an external electromagnet.