Experimental study on the radiation beam scan of a waveguide slot array antenna filled with a ferrite

This paper describes a millimeter wave slot array antenna whose beam direction can be scanned by a bias magnetic field. A rectangular waveguide with radiating slots on the side wall is partially filled with a ferrite slab. The propagation characteristic changes by applying a dc bias magnetic field parallel to the ferrite, so the radiation direction of the leaky waves from the slot array can be scanned. The radiation pattern of a prototype antenna has been measured at 40 GHz. The main beam direction changes from 10 to 3 degree by the bias magnetic field of 0.73 T.