A Time Domain Combined Field Integral Equation for Open Screens

The time-domain electric field integral equation is a versatile tool for the modelling of the scattering of transient fields by perfect conductors. It allows for the inclusion of both closed and open scatterers, and the impact of high but not infinite conductivity can be accounted for by the inclusion of a surface impedance term. Unfortunately, it cannot produce the currents induced on the front and back of a perfectly conducting open screen without further post-processing. Moreover, when a multi-screen treatment is required (when junctions are present for example), the singular time stepping matrix can lead to catastrophic loss of significant digits. To mitigate these issues, this contribution introduces a time domain combined field integral equation for these scattering problems. The equations and their discretisation are introduced and their effectiveness in fixing the above issues is demonstrated by a representative set of numerical examples.