Millimeter-Wave Phased Array Antennas for Defense and Satellite Applications

Abstract

In recent years, the surging demand for high-speed data communication in both military and civilian sectors has positioned millimeter-wave (mmWave) technology as a key solution due to its wide bandwidth and high data rate capabilities. Applications such as low-Earth-orbit (LEO) satellite communications, exemplified by systems like Starlink and OneWeb, particularly benefit from mmWave technology for rapid information transfer and real-time connectivity. These systems leverage mmWave bands to offer high-speed, low-latency communication while reducing the size and weight of satellites and user terminals, requiring robust beam steering to maintain stable links and emphasizing the role of phased array antennas and RF systems. In military applications, missile seekers demand precise beam steering, target tracking, and systems that are lightweight, compact, and capable of high gain. The need for lightweight and compact systems is critical due to the limited space and payload capacities in missile designs. High-gain antennas are essential for enhancing the detection and tracking of distant or small targets. mmWave technology enhances resolution and accuracy, while phased array antennas enable swift electronic beam steering without mechanical parts, improving reliability under dynamic conditions. Similarly, robust beam steering systems are essential for LEO satellite communications to maintain stable links due to the rapid movement and changing angles of satellites relative to ground stations. The development of electronic beam steering modules is thus essential, with a trend toward beamforming for more flexible and precise control—crucial for maintaining communication with fast-moving satellites. However, challenges include expanding the 3-dB axial ratio (AR) coverage for consistent circular polarization in wide-angle beamforming and miniaturizing antenna elements to prevent grating lobes during beam scanning. Fabrication difficulties arise from shorter wavelengths and limitations of conventional manufacturing processes. Addressing these challenges is vital for effective mmWave technology implementation in both military and civilian applications. This thesis focuses on designing planar phased array antennas and mmWave beam steering modules. We propose novel antenna designs, including a sequentially fed rhombus patch subarray for wide-angle circular polarization beamforming in Ka-band communications. In addition, we propose a Ka-band seeker array antenna employing an air-filled Substrate Integrated Waveguide (SIW) cavity structure to achieve a lightweight and compact design while maintaining high gain and efficiency. Additionally, we introduce the development process and performance analysis of a 32-channel Ka-band electronic beam steering module employing beamforming for rapid and accurate beam steering in dynamic environments. Through simulations and experimental validations, we demonstrate that our designs meet the requirements of mmWave applications, contributing significantly to the advancement of mmWave technology and offering promising approaches for future communication systems.