Encapsulated low-noise ultra-high frequency semiconductor device

摘要

An ultra-high frequency transistor is mounted in a hermetically sealed package in order to be made usable and in order to improve its performance characteristics to the optimum level. To diminish the noise factor of an ultra-high frequency transistor, the geometrical dimensions of the gate must be reduced. But the transistor changes its impedance and maximum frequency and can no longer be used in a package or at the external impedance of the circuit. It has to be pre-matched by having a choke mounted between its gate, its drain and the corresponding external connections. Each choke consists of a long metallic wire, forming a hairpin, soldered inside the package between the gate metallization and the internal end of its external connection or between the drain metallization and the internal end of its external connection. The invention can be applied to low-noise ultra-high frequency amplifiers.