A Compact SIW Monopulse Antenna Array Based on Microstrip Feed

In this letter, a compact substrate integrated waveguide (SIW) monopulse antenna array based on microstrip feed is proposed. The antenna cell is composed of two layers of dielectric substrates, the model of the dielectric substrate is Rogers 5880. The TE20 mode is excited in the bottom SIW cavity, and the mirrored TE20 mode is used to realize the function of a monopulse comparator, which makes the structure of the antenna simple and superior in performance. Furthermore, an array is formed on the basis of the cell. The performance of the array was verified in simulated software and the prototype was fabricated for testing. The measured results are consistent with simulated results. The antenna works in the X-band, and the measured and beam gain reaches 16.4 dBi, and the null depth is 33.8 dB. The antenna aperture efficiency reaches 43%, which has great advantages compared with similar antennas.