A new computer analysis method is presented by which the noise contributions of the various noise sources within a MESFET mixer can be determined and its overall single sideband and double sideband noise figure and noise temperature calculated. The method extends Kerr's work on diode type mixers and utilises a frequency conversion matrix of a MESFET mixer. The simulation program was run for a mixer circuit based on an NEC720 transistor, and the results for the noise sources and noise figure behaviour as functions of the LO power are presented and compared to measured values with good agreement. An optimal operating point from the standpoint of minimum noise figure can thus be determined for transistor biasing conditions and the LO input power.
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