Multiple transistor low noise amplifier optimized for cryogenic temperatures
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Solution Overview
Problem
Conventional low noise amplifiers face challenges in adequately mitigating noise and maintaining consistent gain over a range of frequencies, leading to unacceptable levels of signal distortion, additive noise, and excessive thermal noise.
Innovation Solution
The solution involves packaging low noise amplifiers with a Stirling cryocooler to cool the amplifier circuits to cryogenic temperatures, combined with field effect transistors (FETs) arranged in a parallel configuration to reduce noise and improve signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional low noise amplifiers operate at room temperature, then device complexity is low, but noise figure and thermal noise are excessive
Solution Approach 1:
The patent applies parameter changes by transitioning the amplifier operating temperature from room temperature to cryogenic temperatures (below 77K). This fundamental parameter change reduces thermal noise and improves noise figure, directly resolving the technical contradiction between reducing harmful noise factors and maintaining acceptable operating conditions
Solution Approach 2:
The patent introduces a cryocooler as an intermediary device to maintain the amplifier at cryogenic temperatures. This mediator enables the amplifier to operate at low temperatures without requiring complex cryogenic infrastructure, resolving the contradiction by providing a practical temperature control solution
2Stability of the object's composition
If conventional amplifiers use single transistor configuration, then device complexity is low, but gain consistency over frequency range is poor
Solution Approach 1:
The patent applies segmentation by dividing the amplification function across multiple transistors (first and second transistors) operating in parallel. Each transistor handles different aspects of the signal, improving gain consistency across the frequency range while maintaining manageable device complexity through modular architecture
Solution Approach 2:
The patent combines multiple transistors in a parallel configuration where their individual amplification capabilities merge to achieve superior overall performance. This merging of components resolves the contradiction by achieving stable gain characteristics that single transistors cannot provide alone
3Power
If amplifier gain is increased to amplify weak signals, then signal strength is improved, but signal distortion and additive noise increase
Solution Approach 1:
The patent changes the temperature parameter to cryogenic levels, which fundamentally alters the noise characteristics of the amplifier. This enables high gain operation that amplifies weak signals while the low temperature suppresses thermal noise generation, resolving the contradiction between signal amplification and noise control
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces noise figure and return loss, extends the flatness of gain over a broader frequency range, and minimizes circuit control loss, resulting in improved performance for sensitive applications.
Implementation Method 1
packaging low noise amplifiers with a Stirling cryocooler to cool the amplifier circuits to cryogenic temperatures
Data Source
AI summary
The present disclosure is directed to apparatus and method that extends a useful operation range of an amplifier circuit. Here a low noise amplifier may be attached to a cold end of a cooler or chiller, such as a “Stirling” cryocooler after which a chamber that encloses the cold end of the cooler and the amplifier may be assembled. Gas included in the chamber may be removed by attaching an input to a vacuum pump to a portion of the chamber. After the chamber is sealed such that a low pressure in the chamber can be maintained, the cooler may be turned on in order to chill the amplifier to temperatures that reduce noise generated internally to the amplifier or to reduce amounts of return loss associated with the amplifier. The use of a Stirling cryocooler allows for the amplifier to be cooled to very low or cryogenic temperatures.