Higher-Order Impedance Boundary Conditions for Sparse Wire Grids

摘要

Higher-order impedance boundary conditions designed for modelling wire grids of211u001ethin conducting wires are established. The derivation is based on the exact 211u001eanalytical summation of the individual wire fields. This allows to write 211u001eapproximate boundary conditions on the grid surface which connects the averaged 211u001eelectric field and the averaged current (or the electric field and the averaged 211u001emagnetic fields on the two sides of the grid surface). The condition depends on 211u001ethe tangential derivatives of the average current (up to the 6th order). This 211u001eapproach provides an extension of the averaged boundary conditions method (well 211u001eestablished for dense grids) to sparse grids. Numerical examples demonstrate very 211u001egood accuracy of the solution for the field reflected from grids with the wire 211u001eseparation as large as half the wavelength.