Empirical expressions for characteristic impedance of modified microstrip-like interconnections
In this work, we investigate modified microstrip structures  a microstrip line with an aperture in the ground plane below the line and a microstrip line guarded by adjacent ground tracks. Closed-form expressions are presented for the characteristic impedance of these microstrip-like interconnects. The formulae given have been designed for use in PCB, MCM and MIC CAD programs. The predicted results are compared with FDTD simulations and measured data that show excellent accuracy.
characteristic impedance microstrip lines finite-difference time-domain printed circuits multichip module