Research On Millimeter-Wave/Teraherz Waveguide Power Combining Technologies

With the development of wireless communication technology,power dividers/combiners have more and more extensive application in wireless communication system.In the millimeter wave / terahertz(THz)frequency band,the lack of high power signal sources has restricted the development of wireless communication technology.Therefore,the multi-channel power systhesis technology in millimeter wave / THz frequency band is expected to become one of the important way to solve the problem of low power sources.In the millimeter wave / THz frequency band,the traditional planar structure power divider is no longer applicable due to the huge insertion loss,the contradiction between the high efficiency and heat dissipation in the quasi-optical power combining circuits has not been well solved.Compared with the first two structures,the waveguide structure has the advantages of large power capacity,small insertion loss and good heat dissipation performance,and has important application value in the millimeter wave / THz frequency band.This paper focuses on waveguide structure multi-channel power synthesis circuit in millimeter wave / THz frequency band.And the reseaech contents of this article include:1.Based on circular waveguide mode converters,16-way and 4-way power dividers have been designed,processed,measured and analysised about tolerance.The 16-way power divider is designed based on E-T branch circular waveguide mode conversion and the circular waveguide's transition mode is the rotationally symmetric TE01 mode.The measured results show that in the 145~168GHz frequency band,the input return loss is better than-15 dB,the amplitude imbalance is about-13.67±1.02 dB and the phase imbalance is within 28°.Considering the additional insertion loss due to measuring,the synthesis efficiency of the circuit in actual enginnering can reach 85%.The 4-way power divider is designed based on H-T branch circular waveguide mode conversion and the circular waveguide's transition mode is the TM01 mode.The measured results show that in 140~167GHz frequency band,the input return loss is better than 13 dB,the average insertion loss of the circuit is about-7.19 dB,and the phase imbalance is within 16.8°.Considering the additional insertion loss due to measuring,the synthesis efficiency of the circuit in actual enginnering can reach 84%.2.Based on coaxial structure,8-way power dividers and the aquare coaxial broadband Wilkinson power divider have been designed.The 8-way power divider uses coaxial as transition structure,and has two-stage metal cylinder as the matching structure between the coaxial and radial cavity.The measured results show that in 82~110GHz,the return loss is better than-15 dB,and the transmission parameter is about-9.49±0.5dB,the phase imbalance is within 20°,and the synthesis efficiency reaches 90%,showing good performance.Based on the square coaxial transmission lines,the equal-impedance power divider is designed,which has the same performance as the traditional Wilkinson structure and reduces the difficulty of processing and assembly.At the same time,a twostage broadband Wilkinson power divider is also designed,which greatly improves the working bandwidth and has the advantages of broadband,compact structure and high power capacity.