chapter  6
14 Pages

Measurement of Passive Microstrip Circuits

ByAlejandro Dueñas Jiménez

In order to validate the theoretical procedures, this chapter presents the results of the analysis of some microstrip test circuits physical characterization using a commercial network analyzer. The first measurement was done over a simple 25-O microstrip transmission line. The line was constructed using a substrate of polythetrafluoroetilene (Teflon) with a dielectric constant of 10.5 (DUROID® 6010, er = 10.5). The synthesis was carried out with the method of moments (MoM). The obtained dimensions were H = 0.1882 cm and L = 3.7 cm. The network analyzer was calibrated using an open-short-load (OSL) technique with a user two-port calibration for 1600 points. Theoretically, the open circuit can be constructed with a quarter-wave transmission line terminated on a short circuit which shifts by ninety electrical degrees the short circuit point on the Smith chart from 1∠180° to 1∠0°. Strictly, the use of open- and short-circuit standards for a determined technique demands a calibration by parts or segments of a defined bandwidth.