| 摘要 |
PURPOSE: A low noise amplifying device is provided to reduce the noise figure to minimum by reducing the loss of inserting a switch in composing a bypass circuit by using the switch. CONSTITUTION: The low noise amplifying device includes a low noise amplifier(40), the first switch(41), the second switch(42), the first inductor(L41), the second inductor(L43), the third inductor(L44), the fourth inductor(L42) and the third switch(43). The base of the low noise amplifier(40) is connected to the input terminal and the collector of the low noise amplifier(40) is connected to the output terminal. A side of the first switch(41) is connected to the input terminal and the base and the other side of the first switch(41) is connected to a side of the first inductor(L41). A side of the second switch(42) is connected to the output terminal and the collector and the other side of the second switch(42) is connected to the second inductor(L43). A side of the third inductor(L44) is connected to the base and the other side of the third inductor(L44) is connected to the control voltage terminal. A side of the fourth inductor(L42) is connected to the collector and the other side of the fourth inductor(L42) is connected to the control voltage terminal. The third switch(43) is connected to the other side of the bypass line and to the output terminal in series.
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