Millimeter-Wave Broadband Monopulse Radar Antenna for Space Debris Detection

In today’s world, artificial satellites play critical roles in communication, navigation, weather monitoring, and scientific research. However, the increasing presence of space debris poses a significant threat to their functionality and safety. This debris includes defunct satellites, rocket stages, and fragments from collisions with other objects, all orbiting Earth at high speeds. Such debris particles can collide with operational satellites, potentially causing damage or destruction. Such collisions could result not only in financial losses, but could even have other far-reaching ramifications. To address this challenge, this article introduces a novel thin mm-wave monopulse antenna system designed to detect space debris during satellite missions. This system compares amplitude and phase signals received through both sum and difference beams, enabling effective space debris detection. It consists of a tapered slot antenna integrated with a mm-wave rat-race design on parallel transmission lines, implemented on a PCB with a thickness of 0.17 mm. The proposed rat-race has a quadruple arm structure, which holds a 90° electrical length on each arm, unlike the conventional rat-race. With the proposed rat-race, sum and difference signals are generated over a broad frequency range. Based on the measurement results, the proposed monopulse antenna covers a frequency spectrum of 22–42 GHz.