Millimeter-wave Solid-state Power Combining Technology Research

In the millimeter-wave communication system,the improve of the outputpower of system transmitter means better communication quality, stronger anti-interference ability and greater action radius and so many superiority.Due to a single amplifier chip provided the limited output power, the technology of power combining can effectively achieve high output power of the millimeter-wave solid-state system.This paper mainly discussed the research, design, production and test for the millimeter-wave power combining amplifier.It also discussed complication which can affect the combining efficiency and emphasised on the theoretical analysis and reserch of the nonlinear of the power amplifier.The paper has introduced some improving method of the nonlinear of power amplifier. At the same time, the paper presented the design of a Ka-band wide-band power combiner based on the H-plane of waveguide. The combiner demonstrates a wide bandwidth in the frequency range of 29.5～37GHz.The Amplitude imbalance of power combiner lower than 0.4dB,and the return loss and isolation is lower than -19.5dB in the frequency range of 29.5～37GHz.It is key to design low loss, low degree of amplitude imbalance and greater phase consistency of power combining network for the millimeter-wave power amplifier.This paper focuses on the four power combining structure for the 10W and 20W power combining amplifier.Through comparative reserach and analysis,10W power combinning network used waveguide-to-microstrip double probes to achieve two way combinning.20W power combinning network adopted branched-waveguide coupler and waveguide-to-microstrip double probes to achieve four way combinning.These two structures can solve how to place many accessories in finity room and how to improve the phase and amplitude balance in combining structure.In the power device of circuit intergration,these two structures had low loss intergration,thermal performance,compact and other advantages.At last, this paper developed the power amplifier using the spatial power combining technology.The 10W Ka band high-power amplifier can provide 1dB compression output power more than 11W in the 29-31GHz.The gain flatness is±2.7dB. The combining efficiency is more than 84%. When the total output power is which 1dB compression output power rollbacked 3dB, The third intermodulation is more than 17dBc.The highest third intermodulation is 20.7dBc in 30.2GHz. The 20W Ka band high-power amplifier can provide 1dB compression output power more than 21.8W in the 29-31GHz.The gain flatness is±2.2dB. The combining efficiency is more than 83%. When the total output power is which 1dB compression output power rollbacked 3dB, The third intermodulation is more than 17dBc.The highest third intermodulation is 19.8dBc in 31GHz.The results show that this paper's power combining project is feasible.It laid a solid foundation to achieve higher outputpower with the higher efficient of two-way and four-way power combining.