Influence of the shield on the ultrashort pulse decomposition in a modal filter realized on a double-sided printed circuit board

Abstract

A modal filter (MF) with four reference conductors (at the edges of the MF on the outer layers) and with the removal of two diagonal reference conductors is simulated. Using the example of two MFs, the influence of connecting the reference conductors with the shield is evaluated. It is shown that connecting the reference conductors with each other with a shield can eliminate their influence, and the shield can be used as reference conductors. The influence of the shield on the decomposition of the ultrashort pulse in two MF is estimated. The increase in the distance from the conductors to the shield is investigated. It is shown that with increasing the distance, the difference in per-unit-length delays becomes smaller for two MFs. In addition, the amplitude of the first pulse decreases and of the second pulse increases. A greater influence of the shield in the MF without two conductors is revealed.