A Hybrid Antenna Element for Travelling Wave Dual-Plane Monopulse Slotted Waveguide Arrays

A novel antenna element for low loss and low-profile dual-plane monopulse arrays is proposed. The travelling wave array has both sum and difference distributions in azimuth. The designed element is the unit cell of an interleaved slotted waveguide array feeding wideband printed antennas via probes inserted into waveguides from the slots. The use of printed antennas enhances the narrow sidelobe and efficiency bandwidth of the closely-spaced slotted waveguide arrays by up to 20%. The unit cells are modelled as multi-port networks including mutual-coupling effects between sum and difference elements placed in an interleaved manner. This enables a very accurate modelling of the coupling effects between sum and difference arrays