Experimental and Numerical Study of Electromagnetic Parameters of V-Band Planar Meander Slow-Wave Structure

In this work we report the results of numerical simulation and cold-test measurements of electromagnetic parameters of the V-band (50–70 GHz) meander-line slow wave structure. The microstrip meander-line slow wave structure is suitable for using in a millimeter-band traveling wave tube amplifiers. Several samples of copper microstrip meander-line slow wave structure on a quartz substrate consisting of 50 meander periods with input and output couplers were designed and fabricated. The slow wave structure was microfabricated by using our original and novel technology for microfabrication. The technology is based on magnetron sputtering and laser ablation methods. The magnetron sputtering method is used to deposit a thin layer of metal (copper) on a quartz substrate. Then laser ablation is utilized to cut a slow wave structure from the copper layer. This technique is a more facile, flexible and lower cost as compared to photolithography method. Transmission and reflection of microfabricated SWS were measured experimentally and calculated numerically. The results of the experimental cold-test measurements are verified by numerical simulations. Electromagnetic parameters of the slow wave structures were simulated using the finite-element ANSYS HFSS and COMSOL Multiphysics software packages. The results obtained with these two codes are in excellent agreement with each other and good agreement between experimental and numerical results is also observed.