| The performance of the RF front-end determines the working performance of the entire wireless communication system.The amplifier is the core part of the entire RF front-end.In recent years,the monolithic trend of RF front-end circuits has become more and more significant.Compared with traditional board-level RF front-end circuits,MMIC(Monolithic Microwave Integrated Circuit)has many irreplaceable advantages and is used in more and more fields.The monolithic bidirectional amplifier chip is a typical representative of the miniaturization and integration of microwave integrated circuits in recent years.It integrates switches and transmit-receive amplifiers,which can share a set of up-down conversion components in the transmit-receive link and simplify the system structure.Therefore,it gradually becomes a popular research direction.In this thesis,a Ku-band bidirectional amplifier chip is designed using 0.25μm GaAs PHEMT process and the assembly and testing work is completed.Two SPDT switches,a transmit link amplifier,and a receive link amplifier were integrated on this bidirectional amplifier chip.Both the amplifier and the RF switch are powered by a positive voltage.Both amplifiers are self-biased and the receive chain amplifier incorporates negative feedback between source and drain.The working frequency band of the two-way amplifier is 12-18GHz,the small signal gain in the transmitting mode is above 6d B,the measured result of the output 1d B compression point is above 18 d Bm;the small signal gain in the receiving mode is above 6 d B,the measured result of the output 1d B compression point is above 14 d Bm,and the noise figure is less than 4.2d B;The input and output return losses of both transmitting and receiving modes are above 10d B,and the overall size of the chip is 2×2.5mm~2.The test results show that the design can meet the design specifications.In addition,a Ku-band 4-bit digitally controlled attenuator is designed using the same technology as the bidirectional amplifier chip.In a radio frequency transceiver system,an attenuator can be used to control the signal amplitude of a transceiver link,and a digitally controlled attenuator is sometimes integrated in the design of a bidirectional amplifier.4-bit digital attenuator is a common solution method used in the attenuator.This thesis designs a 4-bit digital attenuator that includes a 1d B basic attenuator module,a 2d B basic attenuator module and two 4d B basic attenuator modules.It has a step length of 1d B and can achieve an attenuation dynamic range of 1 d B～11 d B. |
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