Microwave Proximity Sensor Waveguide Free Space Distance Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing proximity sensors have limited detection ranges and are often dependent on the permeability of the metallic object, with fixed bandwidths and minimum detection distances, making them unsuitable for industrial applications and precise measurements.
Innovation Solution
A proximity sensor using a microwave oscillator that emits a free space transmission wave, which is reflected by conductive objects, allowing for the determination of distance based on the reflection factor, independent of object permeability, with a waveguide design that separates the waveguide transmission wave into a free space wave, enabling a broader and more linear measurement range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resonator method is used for distance measurement, then the measurement can be performed, but the distance range is limited and the bandwidth is fixed
Solution Approach 1:
The patent replaces the resonator-based electromagnetic field system with a microwave-based measurement system. The microwave oscillator generates microwaves that propagate through a waveguide, interact with the object, and return signals are processed to determine distance. This substitution enables continuous frequency tuning and broader distance ranges while maintaining measurement precision.
2Length of moving object
If the detection distance increases, then the measurement range expands, but the resonance frequency changes become smaller and detection becomes error-prone
Solution Approach 1:
The patent changes the fundamental measurement parameter from resonance frequency shift to microwave phase and amplitude modulation. The microwave oscillator operates at continuously tunable frequencies, and the distance is determined by analyzing the phase difference and amplitude ratio between transmitted and received microwaves. This parameter change enables accurate detection over extended distances without the diminishing returns encountered in resonator systems.
3Device complexity
If a fixed bandwidth is used, then the device is simpler, but the distance range is constrained
Solution Approach 1:
The patent introduces dynamic frequency tuning capability through the microwave oscillator, which can continuously adjust its operating frequency across a broad spectrum. The evaluation electronics dynamically analyze signals at different frequencies to determine distance. This dynamic operation replaces fixed bandwidth constraints with adaptive frequency selection, enabling extended measurement ranges while maintaining manageable device complexity through integrated control.
4Measurement precision
If the measurement distance approaches zero, then the precision improves, but conventional sensors have a minimum detection distance
Solution Approach 1:
The patent replaces conventional inductive sensing mechanisms with microwave-based detection. The microwave oscillator generates electromagnetic waves at wavelengths suitable for short-range measurement, and the waveguide structure directs these waves toward the target object. The reflection and interference patterns at very short distances are captured and analyzed by the evaluation electronics, enabling detection at distances approaching zero while maintaining measurement accuracy.
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 provides a measurement range up to 10 times broader than conventional sensors, with the ability to detect very small distances near zero, and operates within applicable EMV guidelines without bandwidth constraints, ensuring accurate and flexible distance measurement.
Implementation Method 1
a microwave oscillator 52 which provides an output signal 54, in particular in the form of a transmission wave 16
Implementation Method 2
which the object 12, which is electrically conductive or has at least a electrically conductive surface, reflects as a free space reflection wave 30a
Implementation Method 3
the injection of the transmission wave into the waveguide 22 having a wave mode, which leads to the separation of the waveguide transmission wave into the free space transmission wave at the aperture at the front end of the waveguide
Data Source
AI summary
A proximity sensor for measuring the distance from an object contains a microwave oscillator providing, as an output signal, a transmission wave emitted toward the object as a free space transmission wave reflected by the object, the object being electrically conductive or having at least one electrically conductive surface, as a free space reflection wave and is received by the proximity sensor as a reflection wave. The reflection coefficient is determined from the transmission and reflection waves and is provided by the proximity sensor as a measure of the distance. The transmission wave is guided in a waveguide as a waveguide transmission wave and is injected into the waveguide with a wave mode which results in the waveguide transmission wave being separated at the aperture at the front end of the waveguide into the free space transmission wave and in the free space transmission wave propagating to the object.