Experimental investigations on miniaturized high-frequency vacuum electron devices

Sch. of Phys., Seoul Nat. Univ., South Korea
IEEE Transactions on Plasma Science (Impact Factor: 1.1). 05/2005; 33(2):679 - 684. DOI: 10.1109/TPS.2005.844529
Source: IEEE Xplore


We investigated the foundations for high-frequency vacuum electron devices experimentally, with emphasis on deep etch X-ray lithography: lithographie, galvanoformung, abformung (LIGA) to fabricate a miniaturized interaction circuit and a photonic crystal (PC) resonator to excite a stable high-order mode. The successful operation of a LIGA-fabricated folded-waveguide traveling-wave tube was reported. From such physical considerations as Debye length and photonic band gap, we proposed a reflex klystron adopting a cold cathode and a PC resonator.

Download full-text


Available from: Jin-Kyu So, Jun 23, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The circuits for millimeter wave vacuum electron devices with all circuit elements including an electron beam tunnel are microfabricated by two-step deep-etch x-ray lithography (x-ray LIGA). The discrepancies of eigenfrequency between experiment and simulation are within 1.1% in a coupled-cavity structure and 1.4% in a folded waveguide structure when the operating frequency is about 100 GHz. Furthermore, a measured tolerance of below 2 μm, and a measured surface roughness of 20–70 nm, of LIGA-fabricated circuits implies the two-step LIGA microfabrication has potential applications up to the submillimeter wave region.
    Applied Physics Letters 03/2006; 88(9):091916-091916-3. DOI:10.1063/1.2178770 · 3.30 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Three-dimensional (3D) particle-in-cell simulations of 300 GHz reflex klystrons are presented. 300 GHz electromagnetic wave generation in a resonant cavity is analyzed by using a D simulation model in which all the geometric parameters (such as the grid thickness, repeller shape, beam radius, etc.) are described. When an electron beam of an energy of 1.0 keV and a net current of 8.9 mA is used, the maximum electronic efficiency of energy transfer is observed when the gap transit angle is 0.7pi rad, and the efficiency saturates when the beam current is over 10 mA. Space charge forces produce a shift in the optimum repeller voltage. It is also shown that the effect of the beam temperature is not critical, even though the bunching wavelength of the electron beam is several times smaller than that in conventional vacuum electron devices. Our simulation results show that a microfabricated 300 GHz reflex klystron can directly generate electromagnetic waves with output power levels of several tens of milliwatts.
    Journal of Applied Physics 03/2007; 101(5):4519-054519. DOI:10.1063/1.2710353 · 2.18 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A nonlinear theory is developed to predict the gain of a distributed vacuum amplifier employed with field-emitter arrays. Contrary to conventional expectation, it is shown that density modulation of the electrons in the emitting structure is limited by high resistive losses and electronic damping. Therefore, a modified schematic is suggested with the high-frequency modulator separated from the emitter that only dc bias voltage is applied to. Small-signal calculation shows that 15–25 dB gain with 3 dB bandwidth over 200 GHz at 100–400 GHz frequency band can be obtained within 1–2 cm drift space length with currently available parameters of field emitters and microstrip transmission lines. Nonlinear calculations predict promising performances of good linearity and 13–20 dBm saturated output power. The suggested distributed vacuum amplifier fully based on microelectromechanical systems technologies would open a new era for the devices operating at the border of millimeter and submillimeter bands.
    Physics of Plasmas 09/2007; 14(9):093106. DOI:10.1063/1.2773703 · 2.14 Impact Factor
Show more