Abstract: A monopulse comparator is formed by milling grooves in opposed surfaces of aluminum circular blocks. The milled grooves define a number of waveguides, ports and hybrid junctions. A, B, C and D ports are coupled by respective waveguides to respective side branches in first and second hybrid rings. The series branches of these hybrid rings are coupled by respective waveguides to parallel and series branches respectively of a third ring hybrid ring. One side branch of this hybrid ring is coupled to an azimuth differential port by one of the waveguides. The other side branch is coupled to a termination by a waveguide. The parallel branches of the first and second hybrid rings are coupled by respective waveguides to respective side branches of a fourth hybrid ring. The parallel branch of this hybrid ring is coupled by a waveguide to the elevation differential port. The series branch of this hybrid ring is coupled by a waveguide to the sum port.