| The phase shifter is an important circuit module in the phased array system,and its performance has a huge impact on the overall performance of the phased array system.In this paper,the low error,low power consumption and broadband technology of silicon-based CMOS vector modulation phase shifters are studied,and three phase shifters are designed and simulated.The main research contents and innovations are as follows:1.A high-precision tail current addition and subtraction circuit is proposed.By introducing the MOS transistor gate adaptive bias voltage,the accuracy of the current addition and subtraction operation is guaranteed,and the phase shift coding complexity is simplified while the phase error of the phase shifter is reduced.By introducing current scaling,the power consumption due to current addition and subtraction operation is reduced.Based on the current addition and subtraction operation circuit,a 6-bit low gain and phase error digital phase shifter is designed.The RMS gain error is less than 0.305dB and the RMS phase error is less than 1.75 degree.2.A vector modulator based on two-layer MOS transistor structure is proposed.The MOS transistors used for switching control and providing tail current in the traditional vector modulator are combined into one,which reduces the power consumption of the vector modulator.A new type of tail current bias circuit is proposed,which adopts complementary PMOS current array and controls logic through complementary switches,so that the sum of output tail currents is a constant value in 64 phase-shifting states,and constant gain of the phase shifter is realized.The expansion from one set of current states to eight sets of phase-shifting states is achieved through current exchange switches and quadrant selection switches,which simplifies the complexity of phase shifting encoding.Based on these circuit,a 6-bit low power digital phase shifter is designed.The RMS gain error of the proposed phase shifter is less than 0.125 dB,and the RMS phase error is less than 1.18 degree.3.A vector modulator based on switch amplifier array structure is proposed.By introducing complementary switching amplifiers,the change of the input impedance of the vector modulator under 64 phase-shifting states is reduced,and the effect of the change of impedance on the accuracy of the quadrature signal is reduced.Based on the proposed vector modulator structure,a 6-bit Ku-band broadband digital phase shifter is designed.The RMS gain error is less than 0.245dB and the RMS phase error is less than 1.76 degree.4.Based on two equivalent circuits of transformers,two design methods for broadband matching using transformers are analyzed and deduced.Based on these two methods,two transformer input baluns and two transformer output baluns are designed,which achieve good input and output matching. |
