The thesis explores the use of a 4-channel Vector Network Analyzer (4ChVNA) for in-situ measurement of phased array antennas, crucial in wireless technology. It emphasizes the importance and challenges of in-situ measurement tools like VNA for accurate, immediate assessments. The research focuses on characterizing antenna elements in phased arrays, enhancing understanding of their behavior for IoT sensor antenna performance requirements. This involves employing specialized tools and devising effective measurement strategies. Additionally, it evaluates the frequency response of "L" band phased arrays, offering insights into their operating bandwidth and resonance. Ultimately, this work enhances existing knowledge and sets the stage for future developments in the field.