Josephson Junction DC Switching for Cryogenic Bias Routing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional microwave, electro-mechanical, and electronic switches are not compatible with on-chip integration and cryogenic operation of superconducting electronic circuits due to incompatible fabrication processes and high power dissipation, and tunable filters using superconducting materials face challenges with control by signal levels and operation at cryogenic temperatures, leading to issues like high return loss and poor out-of-band isolation in switching applications.
Innovation Solution
A superconducting DC switch system utilizing Josephson junctions and a magnetic field generator to switch between zero and finite resistance states, allowing for on-chip routing of DC biases by controlling the magnetic field, eliminating the need for external switches and multiple bias sources, and enabling infinite on/off ratios with adjustable on-state current and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If external electromechanical switches are used for routing DC current biases, then switching function is achieved, but physical space is lost and excessive heat is generated that disrupts base temperature
Solution Approach 1:
The patent replaces electromechanical switches with a superconducting circuit-based switching mechanism using Josephson junctions and magnetic field generators. This substitution eliminates mechanical moving parts and the associated heat generation, allowing switching to be achieved through quantum mechanical effects in the Josephson junctions that are controlled by magnetic fields applied via on-chip generators, thereby maintaining cryogenic base temperature stability.
Solution Approach 2:
The patent merges the switching function with the DC bias routing function into a single integrated superconducting circuit system. By combining the Josephson junction switches, magnetic field generators, and DC bias tees into an integrated on-chip system, the patent eliminates the need for separate external electromechanical switches, thereby saving physical space and reducing heat generation while achieving both switching and bias routing functions simultaneously.
2Ease of operation
If conventional electronic switches are used, then switching is achieved, but they are not compatible with on-chip integration and cryogenic operation
Solution Approach 1:
The patent changes the operating parameters of the switching mechanism to be compatible with cryogenic temperatures. By using Josephson junctions that operate based on quantum mechanical effects at low temperatures rather than conventional semiconductor physics, and by controlling them with magnetic fields generated on-chip, the system achieves switching capability that is inherently adapted to cryogenic operation and on-chip integration requirements.
3Adaptability or versatility
If superconducting microwave filters are used for switching, then some filtering is achieved, but return loss is high, bandwidth is limited, and out-of-band isolation is poor
Solution Approach 1:
The patent segments the filtering and switching functions into separate components: the Josephson junction switches handle the switching function while separate superconducting microwave filters handle the filtering function. This segmentation allows each component to be optimized for its specific function, with the switches providing low loss and good isolation, and the filters providing the required frequency selectivity, thereby achieving superior overall switching performance compared to using filters for switching.
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 system provides efficient on-chip switching for superconducting integrated circuits, reducing heat generation, increasing usable bandwidth, and improving out-of-band isolation by leveraging Josephson junctions and magnetic field control to manage DC signals effectively.
Implementation Method 1
a magnetic field generator that is configured to switch from inducing a magnetic field in a plane of the one or more JJs
Implementation Method 2
A DC input signal applied at an input of the one or more JJs is passed through to an output of one or more of the one or more JJs in the absence of an induced magnetic field
Data Source
AI summary
A superconducting DC switch system is provided. The superconducting DC switch system comprises one or more Josephson junctions (JJs), and a magnetic field generator that is configured to switch from inducing a magnetic field in a plane of the one or more JJs, and providing no magnetic field in the plane of the one or more JJs. A DC input signal applied at an input of the one or more JJs is passed through to an output the one or more JJs in the absence of an induced magnetic field, and the DC input signal is substantially suppressed at the output of the one or more JJs in the presence of the magnetic field.