Search

For miniaturized vacuum-tube electron devices at millimeter and submillimeter (THz) bands, the possibility of low-voltage operation is of primary importance. Planar slow-wave structures (SWS) on dielectric substrates are favorable for the low-voltage operation. In this paper, we discuss design, fabrication and cold test of millimeter-wave planar SWSs. We consider the microstrip meander-line SWSs, which are designed for operation in traveling-wave tube power amplifiers with sheet electron beam.

Folded waveguide (FW) is a promising type of slow-wave structure (SWS) for millimeter-wave traveling-wave tubes. Results of development of several millimeter-band FW SWSs are presented. SWS circuits at Q- and V -band are fabricated by CNC-machining. Cold electromagnetic parameters of the SWS characteristics are simulated and reasonable agreement with the results of measurements is observed. Small-signal and large-signal gain is calculated.

A novel technology for microfabrication of millimeter-band planar microstrip slow-wave structures (SWS) is proposed. The technology is based on magnetron sputtering and laser ablation methods. V-band (50–70 GHz) and W-band (75–110 GHz) meander-line SWSs are fabricated and characterized by scanning electron and optical microscopy. Electromagnetic parameters of the developed SWSs are studied by numerical simulation and cold-test measurement. Small-signal and large-signal gain is calculated.

Results of numerical simulation of field emission from emitters with small-scale irregularities are presented. A two-dimensional hyperbolic emitter with a small elliptic irregularity is considered. A possibility of strong enhancement of the field on the irregularity is demonstrated. In such a situation field emission properties are determined by the parameters of the irregularity. Some discrepancies between experimental and theoretical data, presented in literature, are explained.