Microwave Radiometry Sensor Assembly for Shielded Deep Tissue Thermometry
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Solution Overview
Problem
Accurate non-invasive measurement of deep tissue temperature, particularly brain temperature, is challenging due to thermal gradients, electromagnetic interference, and anatomical constraints, especially in pediatric or neonatal patients, with existing methods lacking precision and being prone to external interference.
Innovation Solution
A sensor assembly with a flexible circuit board, shield layer, and coaxial connector, integrated with an inductor, thermistor, and capacitor, designed for impedance matching and electromagnetic interference reduction, combined with a radiometer system for signal processing and reference temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If microwave radiometry is used to detect deep tissue temperature, then non-invasive measurement capability is improved, but sensitivity to external electromagnetic interference worsens
Solution Approach 1:
A shield layer is introduced as an intermediary element between the antenna aperture and the external environment. This shield layer acts as a mediator that blocks harmful electromagnetic interference from wireless communication systems and other sources while allowing the antenna to receive microwave radiation from deep tissue for temperature measurement.
Solution Approach 2:
The harmful electromagnetic interference is extracted and isolated from the measurement system by positioning the shield layer to specifically block external interference sources. The shield layer selectively removes unwanted electromagnetic signals from the environment while preserving the desired microwave radiation from the tissue.
2Adaptability or versatility
If sensor assembly size is reduced to accommodate pediatric or neonatal patients, then adaptability to anatomical constraints is improved, but signal reception capability worsens
Solution Approach 1:
The sensor assembly incorporates a flexible circuit board as its substrate, allowing the entire assembly to be made thin and flexible. This enables the sensor to conform to the small and curved surfaces of pediatric or neonatal patients while maintaining the antenna's ability to receive microwave signals. The flexible nature allows close contact with the skin, improving signal reception despite the reduced size.
Solution Approach 2:
The antenna aperture is designed with specific geometric dimensions and orientation to optimize microwave signal reception in a compact form factor. By carefully controlling the aperture size, shape, and orientation, the antenna maintains effective signal reception capability while the overall sensor assembly remains small enough for pediatric and neonatal applications.
3Measurement precision
If impedance matching components are added to improve signal transmission, then measurement precision is improved, but device complexity worsens
Solution Approach 1:
The impedance matching components (inductor, capacitor, thermistor) are integrated directly into the flexible circuit board alongside the antenna aperture. This merging of multiple functions into a single integrated circuit board structure achieves precise impedance matching for optimal signal transmission while avoiding the complexity of separate discrete components. The inductor, capacitor, and thermistor are electrically connected on the same substrate, simplifying the overall device architecture.
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
Provides precise, non-invasive deep tissue temperature measurement by minimizing external interference and accommodating anatomical constraints, ensuring accurate and reliable temperature determination.
Implementation Method 1
Microwave radiometry offers a non-invasive approach for measuring deep tissue temperature by detecting naturally occurring electromagnetic radiation emitted by tissues
Implementation Method 2
All objects above absolute zero emit electromagnetic radiation, and the intensity of this radiation correlates with temperature
Implementation Method 3
a shield layer positioned above the first surface of the flexible circuit board and configured to reduce electromagnetic interference
Implementation Method 4
a thermistor electrically connected to the inductor and configured to measure skin temperature
Data Source
AI summary
The present disclosure provides a sensor assembly for non-invasive temperature measurement using microwave radiometry. The assembly comprises a circuit board with a thermistor, capacitor, and inductor, where the inductor electrically isolates microwave signals from temperature sensing signals. A coaxial connector is positioned at one end of the circuit board with an antenna aperture at the opposite end. A shield layer extends over the circuit board with a sensor region, transition region, and extended region that are offset from the circuit board components. The shield layer is oriented at an angle relative to the circuit board. The inductor utilizes parasitic capacitance to improve antenna impedance matching, while the capacitor provides microwave signal isolation for the thermistor to prevent interference with signal detection.