New ‘phase shifter’ technology will reduce signal loss in antenna systems

Researchers led by Dr Yi Wang from Birmingham’s School of Engineering created a new type of high-performance ‘phase shifter’ using a liquid Gallium alloy, which varies the phase angle of microwave and millimetre-wave radio signals.

The phase shifter is a key enabling technology for advanced phased array antennas (PAA) which are widely used in mobile base stations, satellites and radar systems. These PAA systems use multiple phase shifters to provide the controlled phase increments that steer the radiation beam (see picture). However current phase shifters typically use semiconductors and suffer from high loss of signal (insertion losses) and relatively poor power handling capability.

Dr Wang said: “An ideal phase shifter would provide a stable, and wide phase angle range with a minimal loss of signal over the operation bandwidth. However conventional phase shifters suffer from signal losses which increase as the phase angle increases, and the phase varies with frequency. Taken together, these issues can cause signal degradation and impair performance. Rectifying this requires additional complicated circuitry and consumes more power, which adds to both the bulk and the running cost of the entire antenna.”