Research On Key Technologies Of Terahertz Solid State Power Combiner

The electromagnetic waves in the terahertz band have the advantages of high penetration,fast transmission rate and low energy.Terahertz solid-state power sources are a key component of broadband communications,biomedical and environmental detection applications,where the power output level of the power source has a direct impact on system performance.The output power of solid-state amplifiers in the terahertz band is limited,and power combining technology can effectively improve the output power of the amplifier.While some progress has been made abroad in terahertz solid-state power combining,China is still in the initial stage.Therefore,this thesis studies the terahertz solid-state power combining technology,which is of great significance for the subsequent improvement of the operating bandwidth,combining efficiency and output power of terahertz solid-state sources.Based on the above background,this thesis studies the terahertz solid-state power combining amplifier,and the main work accomplished is as follows:1.The key factors that affect the power combining efficiency are studied,and the effects of path loss,amplitude phase inconsistency,and inter-port isolation on the combining efficiency are analyzed in terms of the combining network.The key design points of the power combining system are described,which lays the foundation for the implementation of a multiplexed power combining amplifier.2.Research on the key passive structures in the terahertz solid-state power combining system,including basic units such as microstrip probe transitions,gold wire transitions,coplanar magic T,waveguide magic T and four-way combining networks with eight-way combining networks,and a broadband weakly coupled directional coupler were studied.Simulation results show that the coplanar magic T, the waveguide magic T and the combined multi-level binary combining networks have low insertion loss and high isolation.The measured results show that the E-plane waveguide Magic T and H-plane waveguide Magic T have uniform power distribution,low insertion loss and high isolation at 180-240 GHz.20 dB couplers and 30dB couplers have a relatively flat coupling at 175-255 GHz,with fluctuations within ±1dB.3.Designed and completed two sets of single-way power amplifier at 195-225 GHz,with small signal gain over 25 dB and output power greater than 15 dBm.Two-way power combining amplifier was designed using E-plane waveguide Magic T and H-plane waveguide Magic T respectively.At 195-225 GHz,the output power of the two-way power combining amplifier using H-plane waveguide Magic T more than17.5dBm,combining efficiency more than 70.9%,reaching the maximum combining efficiency of 86.6% at 214 GHz.At 195-225 GHz,the output power of the two-way power combining amplifier using E-plane waveguide Magic T exceeds 18.5dBm.4.On the basis of single-way and two-way power combining amplifier,a four-way combining amplifier was designed and implemented.The measured results show that at196-225 GHz,the output power of the four-way combining amplifier more than20.35 dBm,and the average output power more than 21 dBm.Using H-plane waveguide magic T to form 8-way power combining amplifier from 2 sets of four-way combining amplifier.The measured results show that sat 196-225 GHz,the output power of the8-way power combining amplifier exceeds 22 dBm,and reaches the maximum power output power of 23.5dBm at 200 GHz.The combining efficiency exceeds 50.5%,the average combining efficiency is 58.9%,and reaches the maximum synthesis efficiency of 70.5% at 213 GHz.