ANALYTICALLY AND ACCURATELY DETERMINED QUASI-STATIC PARAMETERS OF COUPLED MICROSTRIP LINES

Using modified conformal mapping technique and magnetic-wall approxima tion, closed-form expressions for quasistatic parameters of coupled mi crostrip lines are determined accurately in this paper. They are found to be very accurate when compared with the well-recognized numerical solutions in the literature. Specifically, the present effective permi ttivities for both modes are accurate to within 0.4%, the even-mode ch aracteristic impedance is accurate to within 1.2%, and the odd-mode im pedance is accurate to within 1.8% for w/h greater than or equal to 0. 4 and 3.8% for 0.4 > w/h greater than or equal to 0.1. They are believ ed to be the most accurate closed-form formulas for coupled microstrip lines and should find applications in microstrip computer-aided desig n. In addition, two sets of existing equations have been checked again st exact values or accurate results. According to the comparisons, the y are either unacceptable or partially acceptable. Three data tables i nstead of figures are given for clarity.