Analysis of unbounded and bounded circuits considering finite substrate extent and inhomogeneous dielectric layer

A generalized method of lines algorithm is presented for characterizing unb ounded and bounded circuits. Finite substrate extent and inhomogeneous diel ectric layers are rigorously considered in this field-based model. Radiatin g properties of unbounded regular and irregular microstrip patch resonators and arrays are studied with emphasis on effects of mutual coupling and fin ite dielectric extent on complex resonant frequencies. In addition, unbound ed loss effects for microstrip open-end and 90 degrees angular bend deposit ed on finite substrate as well as chip-to-chip discontinuities are also inv estigated. Our developed algorithm incorporates an absorbing boundary condi tion using the Pade approximation to simulate any potential radiation and l eakage losses for resonator structures while an improved lossy absorbing bo undary condition (LABC) that call handle both propagating and evanescent wa ves is used to determine the unbounded effects for waveguiding structures. Results indicate interesting properties of the finite extent of dielectric substrate on resonance and radiation characteristics, and also on unbounded radiation and leakage losses. Copyright (C) 2000 John Wiley & Sons, Ltd.