Circuit Model for Characterizing the Nearly Linear Behavior of Avalanche Diodes in Amplifier Circuits

Abstract

SUMMARY OF RESEARCH Avalanche Diodes for the Generation of Coherent RadiationThis is a Semiannual Progress Report for the NASA contract covered by Professor Perifield and Professor Steinbrecher and relates work completed during the past period.During the past report period research was completed and a paper prepared for publication describing the nearly linear properties of an avalanche-diode operating as a small signal amplifier. The nearly-linear model that is presented in the publication was derived from physical electronics, agrees very well with measurement, and predicts within a few dB the one dB compression point and third-order intercepts to be expected in an amplifier built with a particular device. All of the model parameters may be obtained by simple measurement. A preprint of this publication is included as part of this report.TheJosephson junction has many interesting high-frequency properties and, possibly, considerable microwave potential as a low-noise amplifier. During the past period our efforts regarding Josephson junctions were directed toward estimating the requirements in facilities and personnel in order to begin, manufacturing Josephson junctions in the laboratory for experimental purposes. A decision on whether to do research on the microwave applications of Josephson junctions awaits the outcome of this initial investigation.Two other devices were studied. These are the PIN diode and the MSM diode. We are interested in developing a nonlinear model for the PIN diode that can be used to predict the fundamental limit on intermodulation distortion created by the PIN diode in switching applications. The MSM diode is a microwave negative resistance device that is very similar in structure to a transistor with the base lead open. It behaves like an avalanche diode in that a negative resistance appears across the terminals of the device when carriers are injected into the depleted region.The MSM diode differs from the avalanche diode in one very important respect : in the avalanche device injected carriers are formed by the avalanche process, whereas in the MSM diode injected carriers come from "punch-through" which results from complete depletion of the drift region of the diode, as in the case of a transistor when punch through occurs. This means that as an amplifier the MSM diode should have a much lower, noise figure than the 18 dB experienced with avalanching devices. In fact, it is expected that the MSM diode may have a noise figure as low as a few dB at frequencies of 4 or 5 gigahertz.During the next period we will concentrate heavily on the MSM diode and on completing the nonlinear models for the PIN diode.

A lumped‐distributed small‐signal model for a class of transit‐time semiconductor devices

“…We identify the parameter d with the length from the rns contact The small-signal model is shown in Figure 4(a) (all noise sources are being removed in the case of smallsignal model). The parameters C2 and C, are also determined by equation (17). In the case of d << W the impedance of our model is the same as the analytical results of theoretical c a l c~l a t i o n s .…”

“…The small-signal model of the IMPAIT diode now can be seen in Figure 3(a) ( V , = 0). Parameters of the model can be determined by equations (13), (16) and (17) In the case of RSi = 0 and G, = 0 we have the exact Read' model.…”