Miniaturization of S-Band Monopulse Antenna Feeding Network Using Substrate-Integrated-Waveguide

In monopulse antenna systems, the feeding network plays a critical role since it provides the sum and difference beams. A hybrid waveguide is a type of four-ports device widely used as a feeding network to produce sum and diff beams. This paper deals with the miniaturization of feeding network monopulse antenna using substrate integrated waveguide (SIW). The proposed feeding network which is developed based on SIW structure will be compared with the conventional one, which has a bulky structure, to determine the miniaturization ratio. Parameters of the feeding network such as physical dimension, return loss, insertion loss, isolation, and phase difference will be analyzed to determine the performance of proposed feeding network after miniaturization. The proposed feeding network is deployed on a double side 1.524 mm thick Rogers RO-4003C dielectric substrate. The characterization results show that the proposed feeding network performs well in each port with the phase difference of 180°. In comparison to the conventional one, the use of SIW structure is ultra-compact and implementable in finite space.