Spurious radiation from microstrip interconnects

The level of spurious radiation from microstrip interconnects, which are modeled as either single or asymmetric parallel microstrip lines terminated by arbitrary complex load impedances, is investigated. The calculation of the spurious radiation requires a knowledge of the current distributions on the microstrip lines, and the first step is to compute these distributions efficiently. This is carried out by using the method of moments in conjunction with closed-form spatial domain Green´s functions that circumvent the need for time-consuming evaluation of Sommerfeld integrals. Once the current distributions on the etches have been obtained, the level of spurious radiation, which is defined as the radiated power crossing the plane parallel to the plane of interconnects, is calculated. The dependence of the spurious radiation on the lengths of the lines and on the termination impedances of the etches is also studied.