| In recent years,with the demand for high-speed communications,millimeter-wave communication has led to a wide range of research,which Ka-band 28GHz becomes one of the hot band of the next generation of mobile communication 5G.However,high-frequency signal in the propagation process will have a large loss,which has an adverse effect on the communication quality.Phased array technology,because of its large antenna gain and high signal to noise ratio,is an attractive solution for this problem.Based on IBM 0.13?m process,a Ka-band fully integrated single-channel and four-channel phased array transmitter front-end chip are designed.The main contents are as follows:(1)Ka-band 1:4 Wilkinson power splitter design.It consists of three 1:2 passive Wilkinson power splitter,each passive Wilkinson power splitter is composed of the?/4 transmission line and isolation resistor.In this design,ADS momentum tool is used to simulate the electromagnetic field to obtain the S-parameter.Through the simulation,its input and output return loss are less than-12dB and-20dB from 27.5 to 28.5GHz,its insertion loss is less than 2.6dB,the isolation between the channels is greater than 20dB.(2)Ka-band 4-bit phase shifter design.It is based on the phase shift principle of the switched LC delay network and consists of 22.5°bit,45°bit,90°bit and 180°bit phase shifters.Through the simulation,the input and output return loss are less than-lOdB of the most phase shift state.The average loss at 28 GHz is-13.7 dB,and the loss of all states changes within 1.2 dB of the mean value.The rms gain error of the loss is less than 1 dB in the operating frequency band.The rms phase error is 7° at 28 GHz and less than 9.3° in the operating frequency band.(3)Ka-band power amplifier design.It is cascaded.by two cascode amplifiers.The overall circuit adopts differential structure.The input and output balun are designed to simultaneously perform impedance transformation and differential to single-ended conversion.The inter-stage matching network is composed of inductance and capacitance.Through the simulation,PA's saturation output power is 18.4dBm,1dB compression point output power is 13.4dBm,the maximum power gain is 22dB,peak and 1dB compression point PAE are 16.6%and 6%,third-order intermodulation point output power is 23.4dBm at 28GHz.(4)Ka-band single-channel and four-channel phased array transmitter front-end design.The single-channel phased array transmitter is composed of a 4-bit phase shifter and a power amplifier.The four-channel transmitter consists of four single-channel circuits and a 1:4 Wilkinson power splitter.The S11 of the single-channel transmitter is less than-lOdB in the operating frequency band.The average gain is 9.2dB at 28GHz,the rms gain error is less than 1dB in the operating frequency band,and the rms phase error is 10° at 28GHz and less than 10.3° in the operating frequency band.The average output power of the power amplifier is 17.9 dBm,the average output power at 1dB compression point is 13.4dBm and the average maximum power added efficiency is 7.5%.For four-channel transmitter,the phase and gain curves of each channel have almost the same frequency characteristics.The isolation between channels is greater than 48 dB in the operating frequency band,and the reverse isolation of each channel is greater than 65 dB. |
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