Compact Ku-band monopulse microstrip stacked patch array antenna with hybrid power divider system

This article will present an array antenna system with a compact size (diameter 190 mm) for a monopulse tracking application working in the Ku band, suitable for placement airborne where there is not much space. The antenna system consists of a monopulse comparator, a power divider system, and four subarray antennas. The monopulse comparator and part of the hybrid power divider are designed on the rectangular dielectric waveguide (RDW). The other part of the power divider and antenna element array is designed on the PCB substrate. The two parts of the power divider system are connected to each other through coaxial cables. Simulation results of the antenna system are obtained as follows: impedance bandwidth (VSWR < 1.8) is about 9%; SLL of the radiation pattern of an array antenna using an unequal power divider system with Taylor distribution (SLL= -20 dB, n = 4) at full range frequency is less than -20 dB. The realized gain of the sum beam is 28 dBi at the center frequency, while the zero depth of the difference beam is better than 20 dB. The excellent features of the proposed design make it a good candidate for two-dimensional monopulse tracking applications.