Abstract: A short ridge waveguide load is described which absorbs and cancels non-radiated electromagnetic energy in continuous slot or discrete slotted antennas. The load achieves a small physical size by using a resonant structure which includes an absorbing ferrite front section positioned within the interior of the waveguide antenna below the slot and a back section of ferrite material also positioned in the interior of the waveguide antenna. This allows for energy to be radiated from the slot while absorbing and canceling the non-radiated energy using a relatively small size load. In a rectangular ridge waveguide configuration, the front section consists of a pair of posts having a trapezoidal, rectangular or triangular shape.

Abstract: A waveguide antenna apparatus which allows accurate and independent control of RF amplitude and phase characteristics while maintaining small, narrow dimensions and a constant external cross-sectional shape. The waveguide antenna apparatus comprises a waveguide section having first and second opposing broad faces, with the first broad face having a continuous curvilinear slot therein, and the second broad face having a continuous ridge thereon. The ridge may vary in width along the length of the waveguide and may also vary in height. The waveguide section generally includes first and second narrow faces. The slot in the first broad face is generally positioned off-center with respect to the waveguide section and is elongated, curvilinear or meandering in shape. Conventional feed and load may be coupled to the waveguide antenna.