RF Phase Shifter Calibration for Insertion Loss Stability
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Solution Overview
Problem
Existing radio frequency (RF) phase shifter circuits exhibit variability in insertion loss depending on phase state selection, and attenuator circuits cause unwanted phase variations with attenuation state changes, particularly as the number of state selection bits increases, necessitating a solution to minimize these effects and calibrate phase and attenuation states effectively.
Innovation Solution
The implementation of a digitally selectable phase shifter circuit coupled with a fine adjustment circuit to equalize insertion loss across all phase states by adding small attenuations, and a digitally selectable attenuator circuit with small phase shifters to equalize phase across all attenuation states, using a calibration process to map each state to desired compensation levels stored in a look-up table or programmable settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a digitally selectable phase shifter circuit is used to change phase states, then phase shifting capability is improved, but insertion loss variability increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the attenuation parameter of the fine adjustment circuit based on the selected phase state. The controller modifies the attenuation parameter to compensate for insertion loss variability, thereby maintaining consistent insertion loss across all phase states while preserving full phase shifting capability
Solution Approach 2:
The patent implements feedback through a controller that monitors the phase state selection and automatically adjusts the fine adjustment circuit's attenuation parameter accordingly. This closed-loop feedback mechanism compensates for insertion loss variations caused by different phase state configurations, resolving the contradiction between adaptability and precision
2Adaptability or versatility
If a digitally selectable attenuator circuit is used to change attenuation states, then attenuation capability is improved, but phase variability increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the phase shift parameter of the fine adjustment circuit based on the selected attenuation state. The controller modifies the phase shift parameter to compensate for phase variability, thereby maintaining consistent phase across all attenuation states while preserving full attenuation capability
Solution Approach 2:
The patent implements feedback through a controller that monitors the attenuation state selection and automatically adjusts the fine adjustment circuit's phase shift parameter accordingly. This closed-loop feedback mechanism compensates for phase variations caused by different attenuation state configurations, resolving the contradiction between adaptability and precision
3Measurement precision
If the number of state selection bits is increased to improve resolution, then state selection precision is improved, but circuit complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the phase shifter and attenuator circuits into coarse adjustment sections (handled by main phase shifter/attenuator circuits) and fine adjustment sections (handled by the fine adjustment circuit). This segmentation allows high-resolution state selection through coordinated control of both sections without proportionally increasing overall circuit complexity
Solution Approach 2:
The fine adjustment circuit serves multiple functions: it compensates for insertion loss variability in phase shifter modes and compensates for phase variability in attenuator modes. This multi-functionality allows the circuit to handle high-resolution requirements without adding dedicated complexity for each function
Data Source
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AI summary
An electronic system that includes a digitally selectable phase shifter circuit and an insertion loss fine adjustment circuit such that the system as a whole exhibits little or no change in insertion loss when changing phase state, and/or a digitally selectable attenuator circuit and a phase fine adjustment circuit such that the system as a whole exhibits little or no effect on phase when changing attenuation state. Included are methods for selecting adjustment control words for such circuits.