Dual Plane Monopulse Comparator Network System using Substrate Integrated Waveguide Hybrid Coupler

ABSTRACT This paper presents a new compact monopulse comparator network system (MCNS) using a modal substrate-integrated waveguide (SIW) hybrid coupler for the first time. The main objective of this research is to evaluate the performance of dual-plane MCNS based on return loss and coupling coefficients. A detailed analysis, design, and implementation of dual-plane MCNS is performed using the four modal SIW hybrid couplers. The sum and difference signals required by the monopulse antenna are generated with the proper orientation of couplers. The in-phase and out-phase characteristics of the couplers are generated using TE102 and TE201 orthogonal degenerate modes. A complete planar and compact SIW structure has a footprint of 58.2 mm × 58.2 mm. MCNS is fabricated on a single-layer Rogers RO4003 substrate with a permittivity of 3.55 and thickness of 0.787 mm using a photo-lithographic process. MCNS provides excellent return loss characteristics at all input and output ports. It measured the isolation better than 20 dB for all output ports in the desired frequency band. It achieved good coupling between all input and output ports. Simulation and measured results show that at 10 GHz, MCNS gives better performance parameters and can be used in monopulse antenna.