Laser Micromachining of 2-D Microstrip V-Band Meander-Line Slow Wave Structures

Vacuum electron devices operating at sub-THz frequencies require miniaturized high-frequency electromagnetic interaction structures manufactured using high-precision micromachining technologies. In this article, we present the results of microfabrication of 2-D planar microstrip periodic slow wave structures (SWSs) on dielectric substrate using magnetron sputtering and laser micromachining. A multistage optimized process that allows a substantial improvement of the fabrication accuracy is presented and discussed in detail. A batch of V-band meander-line SWS circuits is fabricated. Characterization of the fabricated structures by optical microscopy and scanning electron microscopy (SEM) demonstrates dimensional deviation less than $5~\mu $ m. Experimental investigation of cold-test electromagnetic parameters shows good transmission and reflection characteristics.