Microwave Radiometer Using Dual Fixed References for Probe Temperature
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Solution Overview
Problem
Existing Dicke radiometers face difficulties in accurately measuring the temperature of a probe due to the complexity and difficulty in controlling the reference temperature of the reference rod, making it hard to find the moment of matching between the probe temperature and the reference temperature.
Innovation Solution
A radiometer for a microwave receiver that uses two fixed reference temperatures and microwave switches to alternately connect the antenna, first and second reference loads with a demodulator, integrator, and controller to measure the probe temperature based on output voltages from these connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reference temperature of the reference rod is varied to match the probe temperature, then the temperature measurement accuracy is improved, but the device complexity and operation difficulty increase significantly
Solution Approach 1:
The patent changes the parameter approach from dynamically varying the reference temperature to match the probe temperature, instead using two fixed reference temperatures (T1 and T2). The probe temperature is calculated by comparing the probe signal with these two fixed references using a ratio relationship, eliminating the need for complex real-time reference temperature control while maintaining measurement accuracy.
2Measurement precision
If the reference temperature is varied to find the matching moment, then the temperature measurement accuracy is improved, but the ease of operation deteriorates due to difficulty in finding the matching moment
Solution Approach 1:
The patent performs preliminary action by pre-establishing two fixed reference temperatures (T1 and T2) that are higher and lower than the expected probe temperature. This eliminates the need for real-time searching or matching operations, as the probe temperature can be directly calculated from the ratio of signals using these predetermined references, significantly simplifying the operation.
3Device complexity
If a single reference temperature is used, then the device complexity is reduced, but the measurement precision deteriorates due to inability to accurately determine probe temperature
Solution Approach 1:
The patent segments the reference temperature function into two distinct fixed reference temperatures (T1 and T2) instead of using a single reference. This segmentation allows the system to determine the probe temperature more accurately by comparing it against both references and using the ratio relationship, while keeping each reference simple and fixed.
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
The radiometer enables easy and accurate measurement of the probe temperature without varying the reference temperature, simplifying the calculation process and reducing reliance on the characteristics of internal components.
Implementation Method 1
According to Planck's law of blackbody radiation, light radiated from a material, a wavelength of a radio wave, and an amount of a component may be expressed as a function of a temperature
Implementation Method 2
When the radiation power received through a microwave receiver by using the [Mathematical equation 2], i.e., noise power is amplified and finally measured
Data Source
AI summary
A radiometer for a microwave receiver according to an embodiment of the present invention comprises: an antenna line through which radiation power corresponding to the temperature of a probe is received from an antenna; a first reference rod having a first reference temperature fixed in advance; a second reference rod having a second reference temperature fixed in advance; a first microwave switch for selectively switching the antenna line, the first reference load, and the second reference load; a second microwave switch switched with the same clock as the first microwave switch; a demodulator for multiplying a signal output from the second microwave switch by a predetermined gain value and outputting same; an integrator for integrating the signal output from the demodulator; and a controller for measuring the temperature of the probe on the basis of a signal output from the integrator.