Planar Slow-Wave Structures for Low-Voltage Millimeter-Band Vacuum Devices (Novel Approach for Fabrication, Numerical and Experimental Measurements)

A novel technology for microfabrication of millimeter-band planar microstrip slow-wave structures is considered. 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 dielectric substrate. Then laser ablation is utilized to cut a slow wave structure from the copper layer. V-band (50-70 GHz) and W-band (75-110 GHz) meander-line slow wave structures are fabricated and characterized by scanning electron and optical microscopy. Electromagnetic parameters of the developed slow wave structures are studied by numerical simulation. Cold-test measurement are also carried out for microfabricated meander-line slow wave structures. The experimental results are in good agreement with the numerical ones. The proposed technology has significant advantages in cost, speed and flexibility over lithography processes commonly utilized for such applications. The future work will be aimed to expansion of the proposed technology to manufacturing of higher-frequency E-band (110-170 GHz) planar slow wave structures.