Precision microwave measurement of the internal parasitics of tunnel-diodes

This paper reports the results of precision microwave standing-wave measurements using a superheterodyne technique from 4 to 11 GHz on the internal parasitics of tunnel-diodes terminating a coaxial-line. Because of past conflicting conjectures as to the frequency dependence of the series resistance, particular attention has been paid to its accurate evaluation. Errors due to transmission-line attenuation and mount discontinuities have been explicitly eliminated from the measured results. The frequency invariance of the series inductance and junction capacitance is verified; but a new variation of series resistance with frequency is proposed of the form
r=T_{dc}+(af)^{2}
, in accordance with the experimental results. The effect of this variation on the resistive cutoff frequency is discussed and a comparison is made With the relevant results of other researchers.