Ultrashort Pulse Decomposition in Hybrid Protection Devices Based on the Cascade-Connected Modal Filter and Meander Line With Broad-Side Coupling

The paper considers decomposition of an ultrashort pulse (USP) in two hybrid protection devices: the first is based on a 3-conductor modal filter (MF) and a meander line (ML) with broad-side coupling connected in cascade; the second is based on a 4- conductor MF and an ML. The delays of each decomposition pulse at the end of each device were determined. The conditions for the USP decomposition were formulated for each of the hybrid devices. The analysis of the influence of cross-sectional parameters in each MF and ML on the per-unit-length delays of the modes and the output signal amplitude was carried out. The optimal parameters of the device cross-sections were found which ensure the fulfillment of the formulated conditions. As a result, the USP attenuation (relative to half of the e.m.f.) in the structure with a 3-conductor MF was 10.77 times, and in the structure with a 4-conductor MF - 11.92 times.