Compact Monopulse Antenna with Low Sidelobe at Ka-band

A new kind of monopulse antenna at Ka-band with low sidelobe and compact structure is designed in this paper. The feed of the antenna consists of four rectangular waveguides which turn around at the end of the radiating aperture, four short rods which are inserted in the four rectangular waveguides respectively. The sum and difference network can be designed inside of the rectangular waveguides. By adjusting the sizes of the rod and waveguide, a good sum pattern with low sidelobe is achieved. Both the elevation plane and the azimuth plane of the differences patterns are in good agreement.