On slotted waveguide antenna design at Ka-band

This paper deals with the design of slotted waveguide arrays at Ka-band (38 GHz). Practical machining tolerances are considered. In order to achieve low sidelobes throughout it is critical that the centre line of the waveguide broad wall is determined very accurately. An error in this position results in systematic errors in the excitation of the slots. This leads to grating lobe like side lobes, the level of which depends on the amount of misplacement. However, the angle at which the side lobe occurs is independent of the position error.