Research On The Key Circuits And Technologies Of Miniaturized High-power Microwave Front-end

With the rapid development of wireless communication and radar technology,the demand for miniaturized high-power microwave front-ends is increasing daily.The conventional solid-state circuit structure is limited by the circuit size and power handling capability,which is challenging to meet the demand.In order to solve these problems,many scholars have researched various related key circuits,especially in power combiner circuits and circulator circuits,and various new structures and technologies have appeared.These new key circuit technologies have the advantages of high power handling capacity,compact structure,wide bandwidth,and low loss compared to traditional technologies.This thesis proposes several new power combiner and circulator structures based on conventional power combiner and circulator technology.A comprehensive and in-depth study is conducted using theoretical analysis,circuit design and simulation,and experimental verification.The main research results of this thesis contain the following aspects:Firstly,the power combination circuit with high power handling and miniaturization was studied in depth.And based on the power capacity analysis,the enhancement method of the power handling capacity of the power combiner was investigated.A hybrid binary power combiner,a multi-way Wilkison type power combiner,a multi-way Gesyl type power combiner,and a broadband waveguide magic-T structure were proposed,respectively.All three power combiners are implemented based on suspended strip lines.And high isolation characteristics between power division ports and low loss characteristics of transmission are obtained in one operating wavelength range.The combination efficiency is greater than 90%in all cases.The high power capacity demand at the kW level is also met.The proposed broadband waveguide Magic-T with 39.4%relative bandwidth is achieved by combining a suspended band line and ridge-loaded waveguide structure.It has low loss,high power capacity,and compact design and can be widely used in microwave millimeter wave systems.Secindly,the large-size over-mode coaxial vertical conversion circuit based on the power combination technology of GW class has been thoroughly studied,and two largesize over-mode coaxial vertical conversion circuits have been proposed.These two vertical conversion circuits are designed based on the power combination technique.These two vertical conversion circuits achieve broadband response by high sub-mode rejection structure,which effectively solves the problem of difficult high sub-mode rejection of large-size over-mode coaxial vertical conversion structure.Thirdly,the microwave millimeter-wave large-quantity power combination amplifier is thoroughly studied.Firstly,broadband large-quantity rectangular waveguide H-plane parallel radial power combiners based on two types of rectangular waveguideover-mode coaxial waveguide mode converters,flower-shaped and compact,is proposed.The bandwidth frequency response and good processing tolerance characteristics of the two power combiners are achieved by ridge loading matching and mode conversion techniques.Secondly,a large number of rectangular waveguide E-plane parallel radial power combiners based on miniaturized end-fed rectangular waveguide-circular waveguide mode converters are proposed.The processing tolerances are improved by a metal column matching structure while achieving a broadband response.Finally,a comprehensive design of the active power combination amplifier is carried out,and an integrated design scheme containing heat dissipation,power combination network,and power detection circuits are given.Finaly,two N-channel parallel power divider techniques with path number reconfigurability are proposed.Firstly,based on the constant-impedance high-isolation power divider,a method of designing a path-number reconfigurable power divider based on multiple parallel transmission lines is proposed.By controlling the different bias conditions of the p-i-n diodes,the path number reconfigurability can be realized for 2N1 states of N transmission modes of the power divider.Then,in order to address the problems of low power capacity and high loss of reconfigurable path number power divider based on the planar transmission line,the research of reconfigurable power divider with high power capacity is carried out,and a suspended stripline structure with reconfigurable characteristic impedance is proposed.A path number reconfigurable power divider is designed based on it.