SQUID Array Layout With Limited Parallel Loops for Signal Linearity
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Solution Overview
Problem
Existing Superconducting Quantum Interference Filters (SQUIFs) with large numbers of SQUIDs are not sufficiently sensitive, and further improvements in sensitivity, linearity, and dynamic range are needed, particularly for applications involving time-varying signals like RF signals, where non-linearity leads to distortion and noise.
Innovation Solution
A SQUIF structure is designed with a limited number of loops connected in parallel (more than two and less than 20) within each row, and columns connected in series, using high-temperature superconducting materials like YBCO, to maintain sensitivity while reducing overall impedance and improving linearity and dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of SQUIDs are used in a SQUIF array, then sensitivity should improve, but the impedance increases and linearity deteriorates
Solution Approach 1:
The patent divides the large array of SQUIDs into multiple columns, where each column contains a limited number of loops connected in parallel (more than two but less than 20). This segmentation prevents the impedance from becoming excessively high while maintaining sensitivity through the collective contribution of multiple columns connected in series.
Solution Approach 2:
The patent applies different connection configurations to different parts of the array: within each column, loops are connected in parallel with a controlled number (2-20) to optimize local impedance characteristics, while columns themselves are connected in series to accumulate sensitivity. This local optimization resolves the contradiction between sensitivity and impedance.
2Productivity
If more loops are connected in parallel, then dynamic range increases, but linearity deteriorates due to non-linear effects
Solution Approach 1:
The patent uses a partial approach by connecting more than two loops in parallel (providing some dynamic range improvement) but limiting the number to less than 20 (preventing excessive parallel connections that would cause severe non-linearity). This partial action optimizes the balance between dynamic range and linearity.
3Power
If the number of parallel loops is increased, then signal output increases, but noise and distortion increase due to non-linearity
Solution Approach 1:
By segmenting the array into multiple columns with controlled parallel connections (2-20 loops per column), the patent achieves signal output enhancement through multiple columns while preventing the non-linear effects that cause noise and distortion by limiting the parallel connection count within each column.
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
The proposed design enhances sensitivity, linearity, and dynamic range by optimizing the number of parallel loops, allowing for better signal capture and reduced noise, particularly in RF signal detection, while maintaining a compact chip size and reducing power consumption.
Implementation Method 1
A Superconducting Quantum Interference Device (SQUID) is a very sensitive magnetometer and generally comprises a loop of superconducting material with one or two weak links, which are usually implemented as Josephson Junctions. The SQUID generates a voltage that depends on the external magnetic flux
Implementation Method 2
The array comprises a number of at least two columns connected in parallel. Each of the columns comprises multiple rows connected in series. Each of the multiple rows comprises a number of loops connected in parallel... using high-temperature superconducting materials like YBCO
Data Source
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AI summary
This disclosure relates to Superconducting Quantum Interference Apparatuses, such as SQUID arrays and SQUIFs. A superconducting quantum interference apparatus comprises an array of loops each loop constituting a superconducting quantum interference device. The array comprises multiple columns, each of the columns comprises multiple rows connected in series, each of the multiple rows comprises a number of loops connected in parallel, and the number of loops connected in parallel in each row is more than two and less than 20 to improve a performance of the apparatus. It is an advantage that keeping the number of loops in parallel below 20 improves the performance of the apparatus. This is contrary to existing knowledge where it is commonly assumed that a larger number of parallel loops would increase performance.