| 摘要 |
PURPOSE:To reduce a noise temperature by connecting plural semiconductor amplifiers in parallel. CONSTITUTION:The microwave applied to input terminal 1 is subjected to matching by a resonance and impedance matching circuit, namely, input circuit and is applied to FET amplifier circuits 3a and 3b which are connected in parallel. Signals amplified there are applied to output circuit 4 of a resonance and imdedance matching circuit and are subjected to matching and are outputted to output terminal 5. Here, when n-number FET amplifiers are connected in paralle, mutual conductance Gm becomes n'Gm, and the noise temperature is reduced to 1/n in comparison with the use of one FET amplifier. Thus, plural semiconductor amplifiers are connected in parallel, so that anti-phase components of noise can be cancelled mutually by the circular current in the parallel circuit, and the noise temperature can be reduced. |
