Applications of electromagnetic band gaps (EBGs) in microstrip and balanced microstrip lines

This paper presents electromagnetic band gap (EBG)-based periodic microstrip lines and balanced (differential) microstrip lines. Specifically, it is shown that through a proper modulation of the strip width in a microstrip transmission line, a stopband with controllable characteristics can be obtained. These EBG structures are then applied to differential microstrip lines, where it is shown that it is possible to achieve common-mode rejection in a certain frequency band, keeping the differential signals unaltered in that band. This is an interesting approach to implement common-mode suppressed differential microstrip lines without ground plane etching.