Transmission Line Notes From a Classic Text

The formulas used to determine the characteristic impedance of several transmission line configurations when run above a perfect ground plane. Although many of these types are no longer used as stand-alone lines such as transmitter-to-antenna feeders, there is useful information for current designs. If you reduce the scale to millimeters or fractions of an inch, some of these transmission lines resemble multi-layer circuit board systems and metal layers on integrated circuit substrates. With recent techniques in air bridge fabrication techniques for both MMICs and MEMs, the resemblance is even stronger.