Variable-Phase RF Amplifier Gain Stage for Constant Phase Modes
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Solution Overview
Problem
Radio-frequency (RF) amplifiers, particularly low-noise amplifiers (LNAs), face challenges in maintaining constant phase across different gain modes, leading to signal quality degradation and requiring complex calibration processes.
Innovation Solution
A programmable-phase gain stage is implemented in RF amplifiers, utilizing transistors with adjustable effective input inductance and gate-source capacitance, and switchable configurations to provide a desired phase across various gain settings, ensuring approximately constant phase across gain modes without the need for baseband phase calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional RF amplifier designs are used, then the amplifier can provide multiple gain modes, but the phase varies across different gain settings requiring complex calibration
Solution Approach 1:
The patent changes the electrical parameters (capacitance and inductance) of the gain stage to compensate for phase variations across different gain settings. By adjusting these parameters, the circuit maintains a constant phase relationship regardless of the selected gain mode, eliminating the need for complex baseband calibration while preserving multi-gain functionality.
2Adaptability or versatility
If conventional RF amplifier designs are used, then the amplifier can operate in multiple gain modes, but signal quality degrades due to phase variation
Solution Approach 1:
The patent modifies the electrical parameters of the gain stage (specifically capacitance and inductance values) to compensate for phase shifts that occur when switching between gain modes. This parameter adjustment ensures that the phase relationship remains constant across all gain settings, thereby maintaining signal quality and reliability in high-order modulation systems while preserving gain mode flexibility.
3Reliability
If baseband phase calibration is implemented to correct phase variation, then signal quality can be maintained, but the system complexity and processing overhead increase
Solution Approach 1:
The patent replaces the software-based baseband phase calibration mechanism with an hardware-based electrical parameter adjustment in the RF gain stage. By modifying the capacitance and inductance parameters directly in the RF circuit, the phase compensation is achieved at the analog level, eliminating the need for complex digital signal processing and baseband calibration algorithms, thus reducing system complexity while maintaining signal quality.
Data Source
AI summary
Variable-phase amplifier circuits and devices. In some embodiments, an amplifier can include a variable-gain stage having a plurality of switchable amplification branches, with each being capable of being activated, such that a combination of one or more activated amplification branches provides respective gain level and phase shift. The plurality of switchable amplification branches can be configured such that the phase shift provided by each combination of one or more activated amplification branches compensates for a phase shift associated with the amplifier operating with the respective gain level of the variable-gain stage.