RF amplifier and RF amplification method

Abstract

A two-stage RF amplifier is provided. The first stage is a common-emitter transistor arrangement with a purely reactive degeneration impedance and an output impedance with a reactive component matched in frequency response to the degeneration impedance. The second stage is a buffer amplifier. The first amplifier can be designed for high gain which is flat over frequency by virtue of the reactive degeneration impedance. The first amplifier provides input matching, and the buffer provides output matching, with decoupling between the input and output.

Description

technical field [0001] The present invention relates to radio frequency amplifiers. Background technique [0002] Demand for variable gain amplifiers ("VGAs") and broadband low noise amplifiers ("LNAs") is increasing. Such amplifiers are required, for example, in cellular base stations. [0003] Two developments have spurred the need for these amplifiers: increasing small cell base station deployments; and reusing the same IC for various platforms, cellular standards, frequency bands, and broadband applications. Reuse of a smaller number of different ICs for many different base station applications can reduce costs, especially support costs. [0004] Typically, LNAs and receiver VGAs for large base stations are narrowband designs, usually in the RF frequency range of 600MHz to 3.8GHz with input / output impedance matching at 100MHz. [0005] The advantage of these known narrowband designs is that the reactive components (inductors and capacitors) can be mainly used to obtai...

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Problems solved by technology

[0007] However, this wideband low-noise capability needs to be achieved by means of a minimum number of noise components combined with a minimal effect of noise generated by unavoidable noise components

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