Modal filter simulation with losses

Protection of spacecraft on-board equipment against electromagnetic interferences is an actual problem. Much attention is paid to the susceptibility to the excitation of powerful ultra short impulses (nanosecond and subnanosecond impulses). The use of known protection devices to solve this problem is hampered by a number of conflicting require- ments. For example, low mass, high reliability, long life. In addition, ultrashort pulses are able to penetrate into various radio-electronic equipment by passing the instrument shields. Protection potential using the devices based on modal filtering is well known. To simulate these devices, rigorous electro-dynamic approach is applied, which requires high computational costs. Approximate quasi-static approach allows to significantly reduce computational costs. The quasi- static simulation was used in this paper, loss record in conductors was realized by means of exact calculation of the matrix of per-unit-length resistances through a change in the matrix of the per-unit-length coefficients of electromag- netic induction when scaling the cross section of conductors. The effect of losses on the shape and amplitude of the pulses at the output of the modal filter is shown. A comparison of simulation results with electrodynamic and quasi- static approaches taking into account losses is presented. Good consistency is obtained. Quasi-static simulation with losses took much less time than the electrodynamic simulation. Analysis of the results suggests that software-based approaches can be used for modal filter simulation.