A simple feed model that reduces time steps needed for FDTD antenna and microstrip calculations

The finite-difference time-domain (FDTD) method is being widely applied to antenna and microstrip calculations, One aspect of this application is accurately and efficiently modeling antenna and microstrip feeds within the constraints of FDTD approximations. Several relatively straightforward approaches have been suggested, including gap and frill feeds. More complicated approaches, which involve including the coaxial feed cable in the FDTD calculation space, have also been suggested. A related aspect is the desirability of reducing the number of time steps required for FDTD calculations to converge, especially for transient excitation, in this paper rpe illustrate that for many geometries a simple gap model with an internal source resistance pro,ides accurate results while greatly reducing the number of time steps required for convergence.