Cryogenic Tunable Dissipative Circuits for Sideband-Free Frequency Shifting
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Solution Overview
Problem
In low-temperature electronics, accurately tuning and changing the frequency of radio frequency or microwave signals is challenging due to the creation of unwanted sideband signals by traditional methods, and the complexity of passing signals between room temperature and cryogenically cooled environments.
Innovation Solution
The use of tunable dissipative circuits within a cryogenically cooled environment, comprising couplers, a tunable resonance element, and a controllable dissipator element, allows for continuous frequency change through controlled phase modulation, eliminating the need for mixers and optimizing component footprints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional mixers are used to change signal frequency, then frequency modulation is achieved, but unwanted sideband signals are created
Solution Approach 1:
The patent replaces traditional electronic mixers with a tunable dissipative circuit comprising a resonator and controllable dissipator. This substitution eliminates the need for nonlinear mixing operations that generate sidebands, achieving frequency modulation through linear resonant frequency tuning instead. The resonator's frequency is adjusted by controlling the dissipator element, providing clean frequency shifts without spurious signals.
Solution Approach 2:
The invention modulates the resonant frequency of the circuit by dynamically changing the dissipation parameter through the controllable dissipator element. Instead of using fixed-frequency mixers, the system achieves frequency modulation by varying the resonator's natural frequency in response to control signals, thereby avoiding the generation of unwanted sideband frequencies that characterize traditional mixing approaches.
2Ease of operation
If microwave signals are passed between room temperature and cryogenically cooled environments, then signal transmission is enabled, but system complexity increases
Solution Approach 1:
The patent extracts the frequency modulation functionality entirely into the cryogenically cooled environment by placing the tunable dissipative circuit (resonator and dissipator) on the cold stage. This eliminates the need for complex room-temperature mixers and signal processing hardware, requiring only simple signal injection and extraction points at the cryogenic interface. The frequency tuning occurs locally at the quantum device, simplifying the overall system architecture.
3Ease of manufacture
If separate tunable resonance element and dissipator element are used, then component optimization is improved, but circuit footprint increases
Solution Approach 1:
The patent combines the tunable resonance element and controllable dissipator element into a single integrated circuit element or tightly coupled structure. This merging maintains the functional independence needed for separate optimization while minimizing the physical footprint on the cryogenic substrate. The unified structure allows both resonance frequency tuning and dissipation control within a compact area, suitable for integration with quantum processing circuits.
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 enables precise, fine-tuned signal production within the cryogenically cooled environment with reduced interfacing requirements, avoiding unwanted sideband signals and enhancing integration in quantum processing circuits.
Implementation Method 1
a tunable resonance element coupled to said propagation path by at least one of said one or more couplers and a controllable dissipator element coupled to said propagation path by at least one of said one or more couplers. A first control input to said tunable resonance element is provided for changing a resonance frequency of said tunable resonance element
Implementation Method 2
A second control input to said controllable dissipator element is provided for changing a damping rate of said tunable dissipative circuit with a second control signal coupled to said second control input
Data Source
AI summary
A tunable dissipative circuit is presented for shifting a frequency of a radio frequency signal or microwave signal in a cryogenically cooled environment. One or more couplers make couplings between a propagation path and a tunable resonance element and a controllable dissipator element. A first control input to said tunable resonance element allows changing a resonance frequency of said tunable resonance element with a first control signal. A second control input to said controllable dissipator element allows changing a damping rate of said controllable dissipator element with a second control signal.