Computer aided design of planar waveguide monopulse comparator for low height airborne antennas

In this paper, we present the issues of design, fabrication and testing of a planar monopulse comparator for airborne radar antennas. An X-band monopulse comparator has been designed using a side wall coupler as a building block. Individual side wall couplers are optimized using the finite element method. The side wall coupler is converted to an equivalent of magic tee, by adding a quarter guide wave length to one of the input of the side wall coupler. Four such hybrids are connected appropriately using H-plane bends to form a compact two plane monopulse comparator. The theoretical and experimental performances of this comparator are also presented