0.13-/22m CMOS Phase Shifters for X-, K u-, and K-Band

Abstract

Two 4-bit active phase shifters integrated with all dig- ital control circuitry in 0.13- m RF CMOS technology are devel- oped for X- and K u-band (8–18 GHz) and K-band (18–26 GHz) phased arrays, respectively. The active digital phase shifters syn- thesize the required phase using a phase interpolation process by adding quadrature-phased input signals. The designs are based on a resonance-based quadrature all-pass filter for quadrature sig- naling with minimum loss and wide operation bandwidth. Both phase shifters can change phases with less than about 2 dB of RMS amplitude imbalance for all phase states through an associated DAC control. For the X- and Ku-band phase shifter, the RMS phase error is less than 10 over the entire 5–18 GHz range. The average insertion loss ranges from 3d B t o 0.2 dB at 5–20 GHz. The input /49/100/66for all 4-bit phase states is typically 5.4 1.3 dBm at 12 GHz in the X- and Ku-band phase shifter. The K-band phase shifter exhibits 6.5–13 of RMS phase error at 15–26 GHz. The av- erage insertion loss is from 4.6 to 3 dB at 15–26 GHz. The input /49/100/66of the K-band phase shifter is 0.8 1.1 dBm at 24 GHz. For both phase shifters, the core size excluding all the pads and the output 50 /10matching circuits, inserted for measurement purpose only, is very small, 0.33 0.43 mm/50. The total current consump- tion is 5.8 mA in the X- and K u-band phase shifter and 7.8 mA in the K-band phase shifter, from a 1.5 V supply voltage.