Some Recent Theoretical Studies on Open Microstrip

An approximate analytical theory for open microstrip recently developed by the authors was compared with existing theoretical results; however detailed examination pointed up discrepancies among these results for strips of width comparable to or greater than substrate thickness. Since these disagreements appear to arise from approximations made on the charge and current distributions on the strip, the authors undertook an investigation of these distributions for wide microstrip which are reported here. Significant differences are found in contrast to the case of narrow strips, which can affect the accuracy of numerical procedures for finding the effective dielectric constant. An analytical approach to excitation of microstrip by an idealized voltage generator is also discussed.