| 摘要 |
A low-noise amplifier capable of operation in two or more frequency bands of a personal communication services (PCS) receiver or other wireless communication system terminal. An exemplary embodiment of the amplifier includes a single bipolar junction transistor amplification stage. Input and output matching networks for the transistor each include a first series capacitor, a shunt inductor coupled to ground potential, a second series capacitor and a second inductor coupled to a supply voltage. These four elements are used to provide narrowband input or output matches in two distinct frequency bands, such as 900 MHz and 1.8 GHz. The first series capacitors in the input and output matching networks may also be used to provide DC input and output isolation, respectively, and the second inductors of the input and output matching networks may be used to supply DC bias to the base and collector, respectively, of the amplifier transistor. The matching networks may be configured using only lumped inductive and capacitive elements, with values limited to less than about 10 nH and 10 pF, respectively. The amplifier may be configured to provide a minimum gain of 15 dB and a maximum noise figure of 2 dB over 100 MHz-wide bands centered at 900 MHz and 1.8 GHz.
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