Microwave Radiometer Power Cycling for 1/f Noise Mitigation
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Solution Overview
Problem
Microwave radiometers suffer from 1/f noise, which cannot be reduced by increasing integration time or bandwidth, leading to performance degradation, particularly in systems using indium phosphide amplifiers for frequencies over 90 GHz.
Innovation Solution
Power-cycling active components such as amplifiers and A/D converters between each measurement to reset the system, eliminating 1/f noise without reducing integration time or precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Dicke switching is used to reduce 1/f noise, then 1/f noise is reduced or eliminated, but measurement time is reduced and white noise contribution degrades by a factor of 2
Solution Approach 1:
The patent applies preliminary action by power-cycling active components (amplifiers, A/D converters, square law detector) between measurements to reset their initial state before each measurement. This eliminates 1/f noise by ensuring components start from a known state, without requiring time-consuming reference measurements as in Dicke switching.
Solution Approach 2:
The patent implements periodic action by repeatedly power-cycling components between each measurement cycle. This periodic resetting eliminates the cumulative effect of 1/f noise while maintaining continuous measurement capability, avoiding the time loss associated with Dicke switching reference measurements.
2Measurement precision
If integration time is increased to reduce white noise, then white noise is reduced, but measurement time increases
Solution Approach 1:
The patent changes the operational state parameter of active components by power-cycling them between measurements. This parameter change resets components to a consistent initial state, eliminating 1/f noise without requiring increased integration time, thus resolving the trade-off between precision and measurement duration.
3Productivity
If power is continuously applied to active components, then system operates continuously, but 1/f noise accumulates and degrades measurements
Solution Approach 1:
The patent applies preliminary action by power-cycling active components between measurements to reset their initial state. This eliminates 1/f noise accumulation while maintaining continuous measurement capability, as components are quickly reset and ready for the next measurement without significant interruption to productivity.
Data Source
AI summary
Radiometer systems and methods that mitigate flicker (1/f) noise are provided. A microwave radiometer system with accuracy impacted by 1/f noise comprises active components which, between measurements, are powered off and on. By powering the active components off and on, 1/f noise is mitigated. Disclosed systems and methods include performing a first measurement with a sensor of a radiometer, after performing the first measurement, switching power to one or more active components of the radiometer off, the active components comprising one or more of an amplifier, a square law detector, and an A/D converter, after switching the power to the one or more active components off, switching the power to the one or more active components on, and after switching the power to the one or more active components on, performing a second measurement with the sensor.