Title :
A 3-D Analysis of a Microfabricated Ladder Slow-Wave Structure for a Millimeter-Wave Traveling-Wave Tube
Author :
Douglas, Christopher R. ; Lin, Ming-Chieh ; Stoltz, Peter H. ; Smithe, David ; Lee, Jae Seung ; Song, Hoyoung ; Lee, Seok-Hyun
Author_Institution :
Northrop Grumman Corp., Los Angeles, CA, USA
Abstract :
The design and the analysis of a ladder slow-wave structure (SWS) operating at 50 GHz is presented. A 3-D particle-in-cell (PIC) modeling of a ladder SWS is presented for the first time. Compared with a conventional helix circuit, the ladder SWS provides wide bandwidth, high interaction impedance, and ease of manufacturing at millimeter wavelengths. A small-signal code based on Pierce´s theory was developed to determine the dimensions and the small-signal characteristics of the device. Cold- and hot-test simulations were performed using High Frequency Structure Simulator and VORPAL codes. VORPAL, a 3-D PIC simulator that makes use of the conformal finite-difference time-domain method, predicts a small-signal gain of 15 dB and an instantaneous bandwidth of 6% for a 68-period ladder SWS that is driven by a 22-kV and 196-mA electron beam. Dispersion characteristics, large-signal characteristics, and nonlinear-beam dynamics are investigated.
Keywords :
finite difference time-domain analysis; microfabrication; millimetre wave tubes; slow wave structures; 3D particle-in-cell; Pierce theory; VORPAL codes; current 196 mA; electron beam; finite-difference time-domain method; frequency 50 GHz; high frequency structure simulator; microfabricated ladder slow-wave structure; millimeter-wave traveling-wave tube; nonlinear beam dynamics; small signal code; voltage 22 kV; Dispersion; Gain; Impedance; Integrated circuit modeling; Millimeter wave devices; Optical waveguides; Ladder slow-wave structure (SWS); microfabrication; millimeter wave; slow-wave structure (SWS); traveling-wave tube (TWT);
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2010.2076381
