| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve the stability in the high-frequency characteristics of a high-output FET within its operating frequency band without greatly deteriorating the same characteristics, by connecting an RC series circuit consisting of a resistor and a capacitor in parallel to a matching capacitor. SOLUTION: An internally impedance-matched output FET 100 comprises a FET 2 whose source is grounded. A low-pass filter type input matching circuit which has a single LC stage consisting of an inductance L1 and a capacitance C1, is connected to the gate terminal of the FET 2. Further, an RC series circuit consisting of a resistor Rs and a capacitor Cs is connected in parallel to the matching capacitor C1. An output matching circuit formed of a distribution constant circuit 5 is connected to the drain terminal of the FET 2. As a result of this configuration, as long as the capacitance of the capacitor C1 is larger than that of the capacitor Cs, the capacitor Cs makes an impedance compensation, even if the resistor Rs has a comparatively large value, and thus insertion losses of the matching circuit become comparatively small. Therefore, the stability of the FET 100 in its operating frequency band can be improved.</p> |
