ANALYSIS OF A THIN SLOT DISCONTINUITY IN THE REFERENCE PLANE OF A MICROSTRIP STRUCTURE

This paper presents a perturbational approach based upon the spectral domain technique for the analysis of the discontinuity effects introdu ced by a thin slot in the ground plane of a microstrip line. The disco ntinuity problem is formulated in terms of the unknown slot field by u sing the notion of equivalent half-space problems, using a new rigorou s procedure for deriving the TE-TM decomposition of the fields and equ ivalent transmission line models. The perturbation current on the infi nite microstrip is computed once the electric field in the slot has be en derived, and an equivalent circuit for the discontinuity is obtaine d from this perturbation current for the low-frequency regime. Compute d results are presented and compared to the measured data.