Printed transmission lines are widely used in circuits and antennas as they are compact, light weight and broadband in frequency. The microstrip line is a transmission-line geometry with a single conductor trace on one side of a dielectric substrate and a single ground plane on the opposite side. Since it is an open structure, microstrip line has a major fabrication advantage over stripline.
Another advantage of microstrip over stripline is that all active components can be mounted on top of the board. The disadvantages are that when high isolation is required such as in a filter or switch, some external shielding may have to be considered. Given the chance, microstrip circuits can radiate, causing unintended circuit response. A minor issue with microstrip is that it is dispersive, meaning that signals of different frequencies travel at slightly different speeds. Microstrip does not support a TEM mode, because of its filling factor.
All microstrip equations are approximate. The effective dielectric constant is a seen to be a function of the ratio of the width to the height of the microstrip line (W/H), as well as the dielectric constant of the substrate material.
No comments:
Post a Comment