A phased array antenna system employing frequency-upconverted local signals with phase difference

This paper proposes a novel configuration for a phased array antenna system (PAS) that achieves ultra-broadband transmission using millimeter waves. Since it is expected to employ an unprecedented number of antennas, the PAS is required to be compact and cost effective. Generally, the PAS employs phase shifters that are applied to the IF or RF transmission signal lines for beam forming. However, the phase shifter limits the bandwidth of the transmission signal due to the required accuracy of the phase adjustment. A PAS employing phase-controlled RF carriers is a promising configuration for broadband transmission. In the proposed configuration, RF carriers are generated by frequency upconverting the phase-controlled local signals with a lower frequency. To confirm the feasibility of the proposed configuration, a two-branch PAS transmitter with phase-controlled RF carriers is configured and tested. Measurement results show that the phase-controlled local signals that have a frequency lower than that of the RF carriers can be used to control the phase difference between the transmitted RF signals.