Electron gun design for traveling wave tubes (TWTs) using a field emitter array (FEA) cathode

Author

Imura, H. ; Tsuida, S. ; Takahasi, M. ; Okamoto, A. ; Makishima, H. ; Miyano, S.

Author_Institution

Electron. Component Dev. Div., NEC, Kanagawa, Japan

fYear

1997

fDate

10-10 Dec. 1997

Firstpage

721

Lastpage

724

Abstract

We first built two traveling wave tubes (TWTs) using a Spindt-type field emitter array (FEA) cathode. The first FEA-TWT achieved excellent RF performances. However its beam transmission ratio was only 82%, in contrast with more than 99% of a conventional TWT. To improve the beam transmission ratio and other characteristics, we re-designed the FEA electron gun and fabricated a second experimental FEA-TWT. At the current less than 20 mA, the beam transmission ratio of the second TWT was improved as high as 98%. However, when the current was more than 20 mA, space charge effect became significant and beam transmission ratio was rapidly degraded. The test results indicated that the design criteria for FEA electron guns needed to take into consideration the strong influence of space charge and how a good beam transmission ratio could be obtained.

Keywords

cathodes; electron field emission; electron guns; microwave tubes; space charge; travelling wave tubes; 20 mA; FEA cathode; FEA electron guns; RF performance; SHF; Spindt-type; X-band; beam transmission ratio; design criteria; electron gun design; field emitter array cathode; space charge effect; traveling wave tubes; Cathodes; Current density; Electrodes; Electron beams; Electron emission; Electron tubes; Field emitter arrays; Microwave antenna arrays; Space charge; Testing;

fLanguage

English

Publisher

ieee

Conference_Titel

Electron Devices Meeting, 1997. IEDM '97. Technical Digest., International

Conference_Location

Washington, DC, USA

ISSN

0163-1918

Print_ISBN

0-7803-4100-7

Type

conf

DOI

10.1109/IEDM.1997.650484

Filename

650484