A Compact, Wideband, and High Gain Truncated 24×24 Cavity-Backed Slot Waveguide Array Antenna for Ku-Band Radar, Military, and Satellite Applications

This letter presents a wideband, high-gain waveguide-based antenna array using a novel 24 × 24 cavity-backed slot for Ku-band radar, military, and satellite applications. Additionally, an equal-phase unequal-amplitude T-junction power divider is proposed using the Taylor Distribution, which is coupled with a compact monopulse comparator for gain improvement. A 2 × 2 subarrays structure is introduced and optimized for improving the antenna performance at the Ku-band. By utilizing 448 radiating slots and 112 coupling slots, instead of the conventional 576 and 144 slots, the proposed circular-shaped array antenna achieves a significant 21.5% reduction in size and the proposed antenna structure achieves a compact dimension of 186.9<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> × π × 30.1 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>. Experimental results show that the proposed antenna achieves a 19.31% impedance bandwidth (13.4–16.2 GHz) with VSWR ≤ 2, and high directivity, as the peak gain is recorded as 34 dBi. Moreover, the monopulse comparator and array antenna maintains over 80% radiation efficiency (VSWR ≤ 1.5), with a maximum exceeding 90% at 14–15 GHz. Meanwhile, the sidelobe level is suppressed to -26.7 dB and -22.5 dB at E-plane and H-plane, respectively, and the cross-polarization suppression is greater than 50 dB at the center frequency. This wideband, high-gain, cavity-backed slot waveguide-based array antenna has been designed and verified for radar, military, and uplink satellite applications in the Ku-band, showcasing its efficiency and practical applicability.