Multiple transistor low noise amplifier
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Solution Overview
Problem
Conventional low noise amplifiers face challenges in reducing noise, maintaining consistent gain over a range of frequencies, and dealing with signal distortion, additive noise, and excessive thermal noise, particularly in sensitive applications like satellite communications and high-definition audio systems.
Innovation Solution
The solution involves attaching a low noise amplifier to a cold end of a Stirling cryocooler, enclosing it in a vacuum chamber, and reducing pressure within the chamber to cryogenic temperatures to minimize noise generation and improve signal-to-noise ratio, using field effect transistors in parallel configurations and optimizing circuit topologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional low noise amplifiers operate at room temperature, then ease of operation is improved, but noise figure and thermal noise increase
Solution Approach 1:
The patent changes the operating temperature parameter from room temperature to cryogenic temperatures (e.g., 4K or 77K) to reduce thermal noise and improve noise figure. This parameter change fundamentally alters the thermal characteristics of the amplifier components, reducing Johnson-Nyquist noise proportional to temperature.
Solution Approach 2:
The patent utilizes phase transitions of cooling media (liquid nitrogen boiling at 77K, liquid helium boiling at 4K) to achieve and maintain cryogenic operating temperatures. These phase transitions provide efficient cooling mechanisms to sustain the low-temperature operation required for minimal thermal noise.
2Power
If gain is increased to amplify weak signals, then signal strength is improved, but signal distortion and noise are exacerbated
Solution Approach 1:
The patent changes the temperature parameter to cryogenic levels, which reduces the noise floor and allows for higher gain operation without excessive distortion. The lower thermal energy at cryogenic temperatures reduces nonlinear effects in semiconductor devices, enabling cleaner amplification of weak signals.
3Power
If multiple transistors are used in parallel to increase gain, then power gain is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple transistors in parallel configurations to achieve higher power gain and improved bandwidth. By merging the current handling capabilities of multiple devices, the amplifier achieves superior performance metrics while managing complexity through systematic circuit design.
Solution Approach 2:
The patent divides the amplification function across multiple transistor stages, with each transistor handling a portion of the total signal current. This segmentation allows for optimized individual transistor operation while achieving cumulative gain benefits, and facilitates thermal management through distributed heat generation.
4Object-generated harmful factors
If amplifier is cooled to cryogenic temperatures, then noise figure is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the operating temperature parameter to cryogenic levels, which reduces thermal noise and improves noise figure. This parameter change fundamentally alters the thermal characteristics of the amplifier components, reducing Johnson-Nyquist noise proportional to temperature.
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, enhances signal-to-noise ratio, and extends the operational frequency range of amplifiers, making them suitable for modern communication systems including 5G and 6G networks with improved signal strength and reduced maintenance.
Implementation Method 1
attaching a low noise amplifier to a cold end of a Stirling cryocooler
Implementation Method 2
enclosing it in a vacuum chamber, and reducing pressure within the chamber 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.