| The fifth-generation communication system has the characteristic of high speed,low delay,high reliability and large capacity,which can be wildly used in all areas of people’s life the future.It can also push the development of military,communication,transportation,medical and education industries to a more intelligent direction.However,the development of 5G challenges the radio-frequency front end.As the main part fo the RF front end,the millimeter wave power amplifer is the main energy consuming part,which means the optimization design of power amplifer has practical economic significance for energy saving.In addition,the reaserach of silicon-based millimeter wave power amplifer is also very important since it can acceralate the process of the full integration of RF front-end and back-end.However,the efficiency and output power of silicon-based millimeter wave power amplifier are low.The main reason for the low efficiency is the high substrate loss of the silicon-based process,which leads to the high loss of the passive components used in the matching network.The low output power is mainly due to the low breakdown voltage of silicon-based process transistor.Firstly,aiming at the problem of low efficiency of matching network,this paper proposes a general efficiency calculation equation of lossy matching network without any ideal assumption.The equation can include the case that both the load impedance and the target impedance are complex impedances,and consider the influence of lossy inductance and capacitance on matching and efficiency.Through SPICE simulation,the results calculated by the generalized efficiency formula are completely consistent with the simulation results.In addition,for the matching network with full inductance or full capacitance,the generalized equation can provide a very easy way to calculate the efficiency.Based on thisgeneralized equation,in order to optimize the efficiency of lossy matching network,this paper firstly proposes a method to find the optimal two-stage network,and further proposes a top-down splitting algorithm.The top-down splitting algorithm can optimize the efficiency by increase the number of stages of matching network.Meanwhile,this algorithm can effectively control the number of stages of matching network,so that the designer can make a trade-off between the efficiency,the complexity and the area.Compared with previous work,this top-down splitting algorithm Compared with prior works,this proposed algorithm shows largest improvement of the efficiency.In addition,on the global optimization of matching network efficiency,this paper proposes a method to find the optimal target impedance from the perspective of global optimization after considering the loss of lossy matching network.Secondly,in order to enlarge the output power of the silicon-based millimeter wave power amplifier,we have used the triple-stacked transistors structure.In order to make the three transistors have uniform AC voltages,the influence of the base capacitance on the partial voltage of the stack amplifier is analyzed from the analyse of signal equivalent circuit.By properly design,this amplifer can have the largest output power.Finally,a triple-stacked power amplifier operating at 26 GHz is designed based on SiGe 130 nm process.In the design of output matching network,this paper uses Loadpull PAE contour map and lossy matching network analysis method to get the most optimal global target impedance.After the optimal target impedance is obtained,the optimal twostage matching network structure is obtained by using top-down splitting optimization algorithm.The efficiency and bandwidth of the two-stage network are higher than that of the one-stage network.In the design of power amplifier,the electromagnetic simulation software EMX is used to simulate all passive components of power amplifier and extract parasitic lines.The simulation results show that the P1 d B of the whole power amplifier is 25.83 d Bm and the PAE is 23.19% at 26 GHz.In the range of 23-28 GHz,the P1 d B of the amplifier are more than 24 d Bm,and the PAE are more than 20%,this amplifier exhibits a wideband property with large output power and high PAE... |
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