Vector Sum Phase Shifter using Phase Control Linearization Technique

This paper presents a vector sum phase shifter using folding circuits with optimized emitter feedback resistors for phase control linearization. The emitter feedback resistors make pseudo-sine-cosine generator output closer to the true-sine-cosine functions. We introduce a new scheme to analytically determine the emitter feedback resistance. Thanks to this scheme, phase control linearity and output amplitude constantity of the vector-sum phase shifter are improved without any digital pre-calculation or calibration. The measured RMS phase error is 3.3° and output amplitude was 98 ± 7 mV for 5 GHz.