A compact active planar patch antenna array for sub-6 GHz 5G applications

This paper presents the design, analysis, achievement, and validation of a high-performance 64-element planar patch antenna array tailored explicitly for sub-6 GHz fifth-generation (5G) communication systems. Operating at 3.5 GHz and mounted on an FR4 substrate, the antenna array exhibits a high gain of approximately 17.5 dB, with excellent input impedance matching and radiation efficiency. To further enhance the system's performance, the antenna array was integrated with a custom-designed power amplifier based on the BFP640ESD bipolar transistor. This integration enabled the achievement of an active antenna circuit, improving both transmission power and overall system efficiency. The power amplifier was designed using the Advanced Design System (ADS) solver. To ensure reliable operation, key parameters such as power efficiency, input/output impedance matching, and stability were analyzed and achieved. Integrating the power amplifier, the active antenna array was thoroughly tested into simulation and validated at 3.5 GHz. The results demonstrate that the proposed circuit not only meets the required specifications for 5G applications but also offers enhanced performance in terms of signal strength and matching input impedance across a wide bandwidth. This study confirms the benefit of incorporating an active power amplifier with a planar antenna array for modern wireless communication systems.