| 摘要 |
Multi-band or wideband impedance matching in RF amplifiers is disclosed, using variable negative feedback. The feedback is provided by variable impedance connected between the input and output terminals of an inverting amplifier, which may be single-ended, or differential. The variable impedance is used in conjunction with a fixed input impedance matching network to tune the variable impedance to different frequencies. The variable impedance feedback can also be used for gain control, and has the added benefit of stabilizing the amplifier. Both multi-band and wideband amplification can be optimized through the use of the disclosed circuitry and techniques. Use of an output impedance matching network in conjunction with the RF amplifier is optional.
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