Research Of Rectangular-ring Vertex Ellipse Double Curved Bar TWT

As one of the most important vacuum electron devices,traveling wave tubes(TWTs)are widely employed in several specialized fileds,such as biodiagnostics,electronic countermeasures and communication due to their advantages of wide bandwidth,high power and high efficiency.As the core component of TWT,the slow wave structure(SWS)directly determines the TWT amplifier performance.Due to the characteristics of flat dispersion and moderate interaction impedance,the circular helix SWS has been widely used in the field of broadband medium-power TWTs.However,the circular helix operating at high current is most susceptible to backward wave oscillation because of the large space harmonic in fundamental mode.In recent years,the rectangular-ring vertex double-bar(RRVDB)SWS proposed similar to ring-bar SWS and ring-double-bar SWS has excellent ablity to suppress backwave oscillation.under the condition of same dimensional parameters,both the operating frequency and the phase velocity of RF wave of the RRVDB SWS are nearly twice that of the circular helix SWS and rectangular helix SWS,so it is easy to work in higher frequency band.At the same time,RRVDB SWS has a significantly higher interaction impedance than RDB SWS,which can obtain higher electron efficiency and output power.However,the interaction impedance of RRVDB SWS is still relatively low,which limits the increase in output power.In this literature,to further purse high-efficiency and high-power of TWT,a new kind of SWS,named rectangular-ring vertex ellipse double curved bar(RRVEDCB)SWS,is presented for the first time.The main workmanship are as follows:1.The influence of RRVEDCB SWS structural parameters on high-frequency characteristics including dispersion and interaction impedance was studied.Under the same parameters,compared to the high-frequency characteristics of the curved ring bar(CRB)SWS and RRVDB SWS.The results show that,compared with CRB SWS,RRVEDCB SWS has flatter dispersion and higher coupling impedance.Although the dispersion of RRVEDCB SWS is slightly steeper,the coupling impedance is significantly improved compared with RRVDB SWS.2.The Ku-band circular electron beam RRVEDCB TWT is studied and compares with CRB TWT.The result shows that,under the operating conditions of 17200 V and0.5A,RRVEDCB TWT can provide 1580 W peak average power,corresponding to maximum gain and electron efficiency of 45 d B and 18.4%,respectively,and 3-d B bandwidth more than 2.4 GHz,while maximum gain and electron efficiency of the CRB TWT is 42.79 d B and 11.46%,respectively.3.The Ka-band RRVEDCB TWT and SRVEDCB TWT are studied and compare with RRVDB TWT and SRVDB TWT,respectively.The result show that,under the operating conditions of 26100 V and 0.2 A,RRVEDCB TWT can provide peak average power of 610 W.The maximum gain and electronic efficiency are 43.082 d B and 11.7%,respectively,and the 3-d B bandwidth is 3.5 GHz,while the maximum gain and electron efficiency of RRVDB TWT are 42.218 d B and 9.58%,respectively.Under the operating conditions of 16100 V and 0.2A,SRVEDCB TWT produces peak average power of 469 W,corresponding to maximum gain and electron efficiency of39.75 d B and 11.65%,respectively,3-d B bandwidth is 2.5 GHz,while the maximum gain and electron efficiency of SRVDB TWT is 39.15 d B and 10.2%,respectively.