DC Block Patient Isolator Absorber Layout for Radiation Suppression
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Solution Overview
Problem
Microwave generators experience interference from unwanted radiation emitted by DC block patient isolators, which affects the accuracy of sensor signals and fails to meet regulatory radiation limits, particularly impacting the remote temperature probe measurements.
Innovation Solution
A patient isolator for a microwave generator is designed with a DC block grounded to the microwave module, wrapped by proximal and distal absorbers separated by a 6 mm gap, utilizing high loss cavity resonance absorbers to minimize radiation interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC block patient isolator is used to electrically isolate the patient from the microwave generator, then patient safety is improved, but unwanted radiation interference is generated that affects sensor signal accuracy
Solution Approach 1:
A grounded absorber is introduced as an intermediary component between the DC block and the microwave generator environment. This absorber intercepts and dissipates unwanted radiated energy through resistive heating, preventing it from interfering with sensor signals while maintaining the DC block's patient isolation function
Solution Approach 2:
The harmful radiated energy from the DC block is converted into a beneficial effect by using a lossy absorber material that transforms the electromagnetic radiation into heat through resistive dissipation. This converts the harmful interference into harmless thermal energy that is safely dissipated
2Ease of manufacture
If the DC block structure is simplified for ease of manufacture, then manufacturing cost is reduced, but radiation interference increases
Solution Approach 1:
The solution segments the radiation mitigation function from the DC block structure itself by adding a separate absorber component. This allows the DC block to remain simple and easy to manufacture while the absorber handles the radiation interference problem independently
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 solution effectively reduces radiation interference by up to -9 dB at 4.9 GHz, improving sensor accuracy and ensuring compliance with regulatory radiation limits, thereby enhancing the operational reliability and safety of the microwave generator.
Implementation Method 1
a proximal absorber wrapped around a proximal portion of the DC block, and a distal absorber wrapped around a distal portion of the DC block
Implementation Method 2
DC block patient isolators operate with capacitive gaps across breaks in inner and outer conductors of a coaxial waveguide. Low frequency signals see this coupling as high impedance
Data Source
AI summary
A patient isolator for a microwave generator includes a DC block grounded to a microwave module of the microwave generator, a proximal absorber wrapped around a proximal portion of the DC block, and a distal absorber wrapped around a distal portion of the DC block and separated from the proximal absorber by a gap.