| 摘要 |
PURPOSE:To obtain a matching circuit suitable for miniaturization and power saving and improved with input VSWR by arranging a voltage-controlled type element to the matching circuit and changing the element value in a direction canceling mismatching in interlocking with a gate voltage of an amplifier. CONSTITUTION:The matching circuit is provided with the voltage controlled type varactor element 1-10. The control voltage of the element 1-10 is fed in interlocking with the gate voltage and when the capacitance of the element 1-10 at that time is C1, the admittance viewed from a point A to a MOSFET 1-2 is nearly equal to a normalized admittance before the gate voltage is decreased in adding the normalized susceptance by the capacitance C1 of the element 1-10. Thus, even when the gate voltage is decreased and the input capacitance of the FET 1-2 is decreased, the impedance viewed from an input terminal 1-12 to the FET 1-2 reaches the matching point and even when the gate voltage is changed, the matching is attained and then the VSWR approaches the unity.
|
