Waves guided by conductive strips above a periodically perforated ground plane

The propagation of waves along an array of conductive strips situated above a periodically perforated conductive plane is considered. Each conductor possesses zero thickness and finite sheet resistance, and the dielectric is homogeneous. The surface current density on the conductors is approximated by means of a finite number of current elements having rooftop spatial dependence. The transverse electric field is given in terms of the current, and the electric field boundary condition is satisfied in an integral sense over the conductors. This generates a matrix equation whose solution yields the dispersion curve relating the propagation constant to frequency, as well as the current distribution. The simulation results are used in obtaining equivalent transmission-line parameters applicable to the printed circuit boards found in high-performance computers. After defining a characteristic impedance, it is shown that, with proper interpretation, the uniform transmission-line equations for propagation constant and characteristic impedance apply to such computer packages.