| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a low-noise amplifier which has impedance matching broadbanded while preventing the degradation in noise figure. <P>SOLUTION: The low-noise amplifier roughly includes an amplifier circuit 201, a bypass circuit 202, and a parallel circuit 104 for broadbanding. The parallel circuit 104 for broadbanding connected between a mutual connection point between a high-frequency input terminal 1 and an input impedance matching circuit 2, and a ground is constituted by connecting a capacitor 102 and an inductor 103 in parallel, and has the impedance matching broadbanded by setting circuit constants of the capacitor 102 and inductor 103 so that the resonance frequency thereof is close to the center frequency of a desired frequency band of the low-noise amplifier and desired reactance is obtained at frequencies higher than the resonance frequency and at frequencies lower than the resonance frequency, respectively. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
