2.4 GHz antenna array using vector modulatorbased active phase shifters for beamforming

This study presents the analysis and the experimental results of a 2.4 GHz antenna array using vector modulators working as active phase shifters for beamforming. With the use of such an active phase shifter, a continuously controlled 360° phase shifting range can be achieved leading to an efficient beamforming architecture. To show the robustness of this system, a theoretical analysis is first performed in order to quantify the impact of vector modulators l/Q. mismatch on the obtained gains and phase shifts. In the same way, the impact of the vector modulators noisy command voltages is also quantified by system simulations. The experimental results of the 2.4 GHz vector modulators show a maximum relative gain error close to 2.5% and an absolute phase error less than 3°. The measured 1 dB output compression point is -6 dBm. Measurements of the prototype including an array of four ´patch´ antennas controlled by the vector modulators were also performed in an anechoic chamber. The results show good agreement between measured and theoretical radiation patterns.