DocumentCode :
1083579
Title :
Temperature distribution in cylinder symmetric MM-wave devices
Author :
Luy, Johann-Friedrich ; Schmidl, Jürgen
Author_Institution :
Res. Center, Daimler-Benz AG, Ulm, Germany
Volume :
42
Issue :
4
fYear :
1994
fDate :
4/1/1994 12:00:00 AM
Firstpage :
573
Lastpage :
579
Abstract :
A general solution of the nonlinear heat equation for temperature dependent thermal conductivity has been developed in cylinder coordinates. The solution is helpful in the design and analysis of high frequency power devices and circuits. The application to diamond heatsinks leads to a design rule height of diamond≈0.5×radius of diamond. Coplanar circuits with an active device modeled as a focal plane can be analyzed. Due to the temperature dependent thermal conductivity the thermal resistance becomes dependent on the input power. Especially for small radii of the focal plane and large input powers significant deviations from the approximation “constant thermal conductivity” result. The results are used to calculate the maximum current density of monolithically integrated transit time devices. The comparison with experimental results yields a rather good agreement
Keywords :
MMIC; diamond; heat sinks; microwave integrated circuits; solid-state microwave devices; temperature distribution; thermal analysis; thermal conductivity of solids; thermal resistance; coplanar circuits; cylinder coordinates; cylinder symmetric MM-wave devices; design rule height; diamond heatsinks; high frequency power devices; maximum current density; monolithically integrated transit time devices; nonlinear heat equation; temperature dependent thermal conductivity; temperature distribution; thermal resistance; Boundary conditions; Circuits; Cogeneration; Geometry; Heat sinks; Millimeter wave measurements; Temperature dependence; Temperature distribution; Thermal conductivity; Thermal resistance;
fLanguage :
English
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9480
Type :
jour
DOI :
10.1109/22.285062
Filename :
285062
Link To Document :
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