LAUSR

This paper presents the design and the implementation of a fully integrated active phase shifter for beamforming at 5.8 GHz. The proposed circuit, implemented in a 0.25 µm BiCMOS SiGe:C process, is based on an original architecture using an injection-locked oscillator (ILO) associated with an in-phase/quadrature (IQ) modulator. The dynamic behaviour of an ILO is first analysed theoretically and important characteristics are deduced. At 2.5 V power supply voltage and total power dissipation of only 92.5 mW, the proposed circuit allows to obtain a 360° phase shift range and occupies 1.43 mm 2 . This phase shift is synthesised using the ILO for fine-tuning and the IQ modulator for coarse tuning.