Development of a prototype antenna radiation pattern measurement system using Software-Defined Radio

This work presents the design and implementation of an automated prototype system for measuring antenna radiation patterns, using Software Defined Radio (SDR), a stepper motor-driven rotational platform, and custom 3D printed components. The system is powered by a Raspberry Pi processing unit, equipped with a touchscreen interface for real-time control and data visualization. The prototype enables automated 360°sweeps in either the horizontal (azimuth) or vertical (elevation) plane, facilitating signal strength measurements across a broad sub-6 GHz frequency range (70 MHz - 5.9 GHz). The prototype was validated by measuring the radiation pattern of an ultra-wide band (700 to 6000 MHz) flexible antenna under far-field conditions and in non-anechoic environment, demonstrating its practical applicability with acceptable accuracy. Performance was evaluated by comparing the measured radiation patterns against the manufacturer's reference data, yielding a root mean square error (RMSE) and a mean absolute error (MAE) below 0.172 (3.260 dB) and 0.139 (2.625 dB), respectively. These results indicate that the prototype offers a low-cost, reliable, modular, and adaptable solution for antenna characterization, suitable for both academic research and practical telecommunications applications. Furthermore, the hardware and software are open source, promoting ease of replication and enabling future enhancements.