IDENTIFICATION OF PROPAGATION REGIMES ON INTEGRATED MICROSTRIP TRANSMISSION-LINES

There has been a resurgence of interest in the propagation characteris tics of open integrated microstrip transmission lines. This is due in part to the discovery of diverse propagation regimes for higher-order modes on open lines. In contrast to the dominant EH(o) mode, three dis tinct propagation regimes exist for higher-order modes on microstrip t ransmission lines. In this paper, a rigorous spectral-domain integral equation formulation is used to analyze propagation in all three regim es. This formulation provides a clear physical picture of the differen t propagation regimes based on the mathematical location of poles and branch points in the complex spectral-variable plane. As an illustrati on, the formulation is applied to the case of an isolated uniform micr ostrip transmission line. The integral equation is discretized via the method of moments, and entire-domain basis functions incorporating su itable edge behavior are utilized to provide convergence with relative ly few terms. The results obtained are compared to the results of othe r workers, and good agreement is observed.