Broadside-Coupled Attenuator Layout Without Looped-Back Output Lines
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Solution Overview
Problem
Low-density broadside-coupled attenuators occupy significant physical space, leading to pitch degradation of control signals due to their looped-back output lines, which is undesirable in superconducting qubit applications.
Innovation Solution
The implementation of reflectively-terminated input lines within broadside-coupled attenuators, where the downstream end is either shorted or open from ground, eliminates the need for a looped-back output line, allowing for a more compact and high-density design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-density broadside-coupled attenuators are used, then thermal noise performance is maintained, but physical space consumption increases and pitch degradation occurs
Solution Approach 1:
The patent inverts the conventional attenuator architecture by using a reflectively-terminated input line instead of a looped-back output line. The input line is terminated with a reflective termination (open or short circuit) at its downstream end, causing the signal to reflect back toward the upstream end where it couples to the output line through broadside coupling. This inversion eliminates the need for looped-back output lines while maintaining the thermal noise performance of broadside-coupled attenuators.
Solution Approach 2:
The patent extracts and eliminates the looped-back output line structure from the conventional attenuator design. By removing this redundant structural element and replacing it with a reflectively-terminated input line, the design achieves high density without compromising the thermal noise performance that depends on the broadside coupling mechanism.
2Reliability
If low-density broadside-coupled attenuators are used, then thermal noise performance is maintained, but pitch degradation of control signals occurs
Solution Approach 1:
The patent inverts the conventional attenuator architecture by using a reflectively-terminated input line instead of a looped-back output line. The input line is terminated with a reflective termination (open or short circuit) at its downstream end, causing the signal to reflect back toward the upstream end where it couples to the output line through broadside coupling. This inversion eliminates the need for looped-back output lines while maintaining the thermal noise performance of broadside-coupled attenuators.
Solution Approach 2:
The patent transitions from a two-dimensional looped-back layout to a more compact arrangement by utilizing the reflective termination approach. The signal path is folded back in time rather than space, allowing the attenuator to achieve high density without increasing the physical footprint or degrading the control signal pitch.
3Area of stationary object
If reflectively-terminated input lines are used, then physical space is reduced, but device complexity changes
Solution Approach 1:
The patent uses simple open or short circuit terminations instead of complex resistive termination networks. These reflective terminations are structurally simple and easy to implement, reducing manufacturing complexity while achieving the desired compact form factor. The terminations are essentially disposable structural features rather than active components requiring precise matching or adjustment.
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 reduces the physical size of the attenuators and minimizes pitch degradation, maintaining thermal noise performance while reducing spatial consumption.
Implementation Method 1
a reflectively-terminated input line that is broadside-coupled to the output line
Implementation Method 2
a downstream end of the reflectively-terminated input line can be shorted to ground. In other cases, a downstream end of the reflectively-terminated input line can be open from ground
Data Source
AI summary
Systems and techniques that facilitate high-density embedded broadside-coupled attenuators are provided. In various embodiments, an attenuator can comprise an output line. In various aspects, the attenuator can further comprise a reflectively-terminated input line that is broadside coupled to the output line. In various instances, a downstream end of the reflectively-terminated input line can be shorted to ground. In other instances, a downstream end of the reflectively-terminated input line can be open from ground. In various cases, the output line can exhibit a non-looped-back-layout.