An X-band 6-bit active phase shifter

This paper presents a 6-bit active phase shifter using a new vector-sum method for X-band (8-12 GHz) phased arrays in 0.13 μm SiGe BiCMOS process. An RC filter is used to generate two orthogonal vectors which are then fed into four VGAs, two using the common-base and two using the common-emitter topology. This generates 4 vectors of 0°, 90°, 180° and 270° which are scaled and added by varying the gains of the VGAs to generate any phase between 0-360°. The gains of the VGAs are adjusted with analog voltage control using the current-steering method. The outputs of the VGAs are connected together with a common load in order to add the vectors in current-domain. The phase shifter achieves <; 5.6° RMS phase error over 8-12 GHz and <; 3.1° RMS phase error over 9-11 GHz. The phase shifter has a power consumption of 16.6 mW from a 2V supply. The chip size is 850 μm × 532 μm including the probing pads. These performance parameters are comparable with the state of the art of the technology in literature.