Evaluation of Mechanical Torque Acting on Scatterer in Microwave Vortex Fields

This letter discusses the generation of vortex fields in microwave frequency range using a corrugated waveguide and a dielectric plate which has a spiral structure. Quantitative investigation of the microwave vortex field is carried out by numerical simulations of the finite-difference time domain (FDTD) method. In addition, the mechanical torque acting on a scatterer in the microwave vortex field is evaluated aiming to use the application for remote manipulation of macroscopic objects.