RF Power Detector Envelope Amplifier Feedback Linearization
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Solution Overview
Problem
Existing RF power detector circuits lack linear response, temperature compensation, and directional coupling, making them unpredictable and sensitive to unwanted RF signals and ambient noise.
Innovation Solution
An RF power detector circuit incorporating an envelope amplifier and a current mirror circuit with feedback to reduce bias signal magnitude, providing a linearized dynamic range and temperature compensation, while using a tapping network and low-pass filters for directional coupling and frequency compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional RF power detector circuits are used, then the circuit structure is simple, but the response is non-linear and measurement precision is poor
Solution Approach 1:
The patent implements feedback by feeding back a portion of the amplified envelope signal to the current mirror circuit to dynamically adjust the bias signal magnitude. This feedback mechanism linearizes the detector response across its dynamic range, directly improving measurement precision while accepting increased circuit complexity as a necessary trade-off
Solution Approach 2:
The patent employs dynamic biasing through the current mirror circuit, where the bias signal magnitude is dynamically adjusted based on the amplified envelope signal magnitude. This dynamic adaptation enables the circuit to maintain linear response characteristics across varying input power levels, resolving the contradiction between measurement accuracy and circuit simplicity
2Stability of the object's composition
If conventional RF power detector circuits are used, then the circuit structure is simple, but temperature stability is poor and outputs vary with operating temperature
Solution Approach 1:
The feedback loop monitors the amplified envelope signal and adjusts the bias signal accordingly, creating a self-regulating mechanism that compensates for temperature-induced variations. This feedback-based temperature compensation improves stability while increasing circuit complexity
Solution Approach 2:
The detector circuit uses its own output signal (the amplified envelope) to automatically adjust its bias conditions through the current mirror circuit. This self-service mechanism enables the circuit to compensate for temperature effects without external intervention, improving temperature stability at the cost of increased internal circuit complexity
3Object-affected harmful factors
If conventional RF power detector circuits are used, then the circuit structure is simple, but the detector is sensitive to unwanted RF signals and ambient noise
Solution Approach 1:
The patent extracts only the envelope information from the RF signal through the envelope amplifier circuit, discarding the high-frequency carrier and unwanted signal components. This extraction process inherently rejects unwanted RF signals and ambient noise while maintaining the desired power measurement function, improving immunity to interference at the cost of added circuit complexity
Data Source
AI summary
RF power detector employing an envelope amplifier circuit and a current mirror circuit. The output of the current mirror circuit supplies a bias voltage for biasing the output of the envelope amplifier circuit. Furthermore, the output of the envelope amplifier circuit is fed back to the output of the current mirror circuit so as to reduce the magnitude of the bias signal according to the magnitude of the amplified RF signal envelope. In this manner, the overall gain of the RF power detector can be selectively reduced, resulting in an RF power detector having a more linearized dynamic range and greater ability to compensate for variation in gain caused by temperature.