Performance Of IMPATT Diodes Research Articles

Final comments on "Effects of carrier diffusion on the small-signal performance of IMPATT diodes"

Final comments on "Effects of carrier diffusion on the small-signal performance of IMPATT diodes"

Degradation of the power- and frequency-temperature performance of IMPATT diodes at lower frequencies

Investigations of the effect of ambient temperature on the RF power and frequency of X -band p+-n-n+ Si IMPATT diodes at frequencies and temperatures below their optimum conditions show considerable degradation of performance. A simple model is presented to explain these effects in terms of a lower limit to the instantaneous terminal voltage of the diode. Values of diode negative conductance are derived from the measurements and good agreement is obtained with independent measurements. The effects are relevant to both amplitude and frequency stability in wide band applications of IMPATT diodes.

Resonant-cap structures for IMPATT diodes

A series of measurements at 10 GHz giving the performance of IMPATT diodes obtained when varying the parameters of a cap circuit are presented. The results indicate that, with correctly chosen parameters, the circuit is suitable for operation over a 40% bandwidth.

High-power IMPATT diodes on diamond heat sinks

This paper presents calculated and experimental results which demonstrate that the performance of IMPATT diodes is significantly improved by the use of diamond heat sinks. Oscillator test results on germanium IMPATT diodes at 6.2 GHz indicate about 50 to 100 percent increase in power output for diamond versus copper heat-sinked units without compromising other oscillator characteristics. An increase in thermal conductance of about 40 percent is realized for diodes mounted on selected high-conductivity diamonds compared to units mounted on copper. Considerations of IMPATT wafer design for optimum power performance on high thermal conductance heat sinks are discussed. Thermal conductivity of naturally occurring diamonds ranges from 1.0 to 5.0 times that of copper which necessitates selection of stones to realize maximum thermal conductance. This paper presents the results of a study of diamond thermal conductivity, its measurement, and its relationship to diamond optical properties. The dependence of diode thermal conductance on die area for diamond heat-sinked devices has been obtained by computer solution of the heat flow equations for the relevant geometries. These calculations have been corroborated by measurement of the thermal conductance of diodes with various die diameters.

The performance of IMPATT diodes under the influence of gamma radiation

IMPATT diodes have been tested under the influence of 1.85×106R/h gamma radiation from a 1.5- MeV Van de Graaf generator. No measurable change in performance has been observed during or after irradiation. A 100 to 300-fold increase in bias current was measured in the preavalanche region of operation.

The performance of IMPATT diodes under the influence of high-intensity gamma and neutron radiation

IMPATT diodes were tested under the influence of up to 1.5 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> R/h gamma radiation and 3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> N/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /s fast neutrons. Major changes were noted in power output, frequency spectrum, and current-voltage characteristics. Permanent damage and total failure resulted from this test.