Analysis of circular symmetric coupled strip and microstrip transmission lines



n this paper, a new kind of coupled line called circular symmetric coupled strip or microstrip transmission line is introduced. These kind of coupled lines are less sensitive to external electromagnetic interference and can also be designed for large scale and low crosstalk interconnects. First, an exact expression of capacitance and inductance matrices (both for strip and microstrip structures) is derived using the Quasi-TEM approach and Laplace equations. Then, these matrices have been diagonalized to get to a set of single partial differential equations describing the system of coupled circular transmission lines and also a simple method for diagonalizing these matrices is presented. Finally some time domain examples derived from the frequency domain are given to show the properties of the structure.