Equivalent Series Inductivity of a Narrow Transverse Slit in Microstrip

The series inductivity introduced by a narrow transverse slit in a microstrip transmission line has been evaluated theoretically, and a simple formula for this inductivity is presented. Experimental results for slits of different depth obtained with the resonant ring method compare well with theory. Applications of such a slit include the fine tuning of the electrical length of stubs and the compensation of excess capacitances at discontinuities.