| 摘要 |
PROBLEM TO BE SOLVED: To realize characteristics of having a small change of phase noise due to oscillation frequencies, and being tuned with a broad band and miniaturization of an integrated bias circuit. SOLUTION: A tuning circuit is constituted of a serial resonance circuit consisting of a varactor diode 2 and a serial inductor 3, and an impedance transformer 4 that reverses the impedance at a desired oscillation frequency, a negative resistance amplification circuit is constituted of a field-effect transistor 1 and a feedback inductor 5 and a part of oscillated power to be outputted to a load resistor 7 is fed back to the input side by a capacitor 6. The impedance transformer 4 (impedance transformation ratio n) reverses the impedance of junction capacitance (C<SB>j</SB>) between the varactor diode 2 and an equivalent serial resistor (R<SB>s</SB>), transforms them into parallel circuits between inductance (C<SB>j</SB>/n<SP>2</SP>) and conductance (n<SP>2</SP>R<SB>s</SB>), in addition, reverses the impedance of serial inductance (L<SB>s</SB>) and transforms it into parallel capacitance (n<SP>2</SP>L<SB>s</SB>). COPYRIGHT: (C)2003,JPO
|
