Formulas of microstrip with a truncated substrate by synthetic asymptotes - A novel analysis technique

A substrate is usually truncated far enough to avoid disturbing the microst rip-line characteristics. Such uneconomical practice is not necessary if th e disturbances as a function of truncation are known in formulas and, there fore, are easily compensated. This paper derives the desired formulas from the novel technique of synthetic asymptotes. Truncation at both sides of a line is derived here with 3% average error. For the practical one-sided tru ncation at the edge of a chip or circuit board, the average error is only h alf at 1.5%.