Definition and determination of the series inductance of tunnel diodes

For the application of tunnel diodes in the microwave region it is important that the series inductance of the diodes is well below one nanohenry. Such small inductances are very difficult to measure. A method is described here by which the inductance can be calculated. The key point of the procedure is a new parameter called the effective radius of a tunnel diode. It is the radius of a cylindrical conductor which can be substituted for the diode in inductance calculations. Experimental determination of the effective radius is shown. The approach taken readily leads to a concise definition of the series inductance of tunnel diodes.