Josephson Microwave Switch Routing with a Single Bias Line
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Solution Overview
Problem
Conventional microwave switches are not compatible with on-chip integration and cryogenic operation due to incompatible fabrication processes and high power dissipation, and tunable filters face challenges with control by single flux quantum technologies and operation at cryogenic temperatures, leading to issues like high return loss, limited bandwidth, and poor out-of-band isolation.
Innovation Solution
A superconducting switch system using a single bias line with varying mutual inductive coupling to Josephson junctions controls impedance, allowing signal routing without individual bias lines, reducing cabling and packaging requirements, and enabling on-chip integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional microwave switches are used, then switching function is achieved, but compatibility with on-chip integration and cryogenic operation is lost due to incompatible fabrication processes and high power dissipation
Solution Approach 1:
The patent replaces conventional mechanical and electro-mechanical switches with a superconducting Josephson junction-based switch. This substitution eliminates moving parts and mechanical actuation, enabling on-chip integration while operating at cryogenic temperatures with minimal power dissipation. The Josephson junction uses quantum mechanical tunneling effects to achieve switching functionality without mechanical components.
Solution Approach 2:
The patent changes the operating temperature parameter from room temperature to cryogenic temperatures, enabling superconducting operation. This parameter change allows the use of superconducting materials and Josephson junctions that exhibit zero resistance and minimal power dissipation at low temperatures, resolving the contradiction between integration compatibility and power consumption.
2Ease of operation
If individual bias lines are used for each Josephson junction, then precise impedance control is achieved, but device complexity and cabling requirements increase
Solution Approach 1:
The patent merges multiple individual bias lines into a single shared bias line that serves multiple Josephson junctions. This consolidation reduces the number of separate control lines and packaging requirements while maintaining the ability to control each junction's impedance through the common bias line, thereby reducing device complexity without sacrificing control precision.
Solution Approach 2:
The single bias line is designed to serve multiple functions by controlling the impedance of multiple different Josephson junctions simultaneously. This multi-functional approach allows one bias line to replace what would traditionally require multiple separate bias lines, reducing cabling requirements while maintaining precise control over each junction's operating state.
3Adaptability or versatility
If conventional tunable filters are used, then frequency tuning capability is achieved, but operability at cryogenic temperatures and control by single flux quantum technologies is limited
Solution Approach 1:
The patent replaces conventional mechanical tunable filters and active electronic components with a superconducting Josephson junction-based filter. This substitution enables operation at cryogenic temperatures where conventional components fail, while maintaining frequency tuning capability through the quantum mechanical properties of the Josephson junction and its response to single flux quantum inputs.
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 facilitates efficient on-chip microwave signal routing with reduced space and cabling needs, supporting multiple outputs and wide-band performance without separate switches for various frequencies.
Implementation Method 1
a mutual inductive coupling between the bias line and the respective JJ of at least two switch network circuits of the plurality of switch network circuits are different from one another
Implementation Method 2
each having a respective Josephson junction (JJ) coupled to a respective transmission line
Data Source
AI summary
A superconducting switch system includes a plurality of switch network circuits, each switch network circuit having a respective Josephson junction (JJ) coupled to a respective transmission line. The superconducting switch system furthermore includes a bias line coupled to each of the respective JJs such that a mutual inductive coupling between the bias line and the respective JJ of at least two switch network circuits of the plurality of switch network circuits are different from one another. A bias line current to the bias line controls the passing or blocking of a received input signal to an output for each of the plurality of switch network circuits by controlling an impedance of the respective JJ of each of the plurality of switch network circuits, the impedance of the respective JJ being determined based on the bias line current and the mutual inductive coupling between the bias line and the respective JJ.