Diplexed Near-Field Sensor Antenna Isolation and Energy Dissipation
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Solution Overview
Problem
Existing near-field sensors face challenges in efficiently dissipating energy stored in the probe after transmission, leading to unacceptably high stress on switch components and compromising performance due to the dual use of a single conductive path for both transmit and receive functions, as well as issues with environmental noise in RF spectroscopy systems.
Innovation Solution
A near-field sensor device with an antenna system featuring electrically isolated conductive paths for transmit and receive functions, utilizing a transmit matching network with crossed diodes and capacitors to dissipate energy, and a receive matching/suppression network with impedance matching and transient suppression to minimize residual energy, thereby reducing stress on components and improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single conductive path is used for both transmit and receive functions, then device complexity is reduced, but performance of transmit and receive functions is compromised and isolation between signals is insufficient
Solution Approach 1:
The patent divides the single conductive path into two separate conductive paths: a first conductive path for transmit functions and a second conductive path for receive functions. This segmentation provides electrical isolation between transmit and receive signals, improving signal isolation performance while maintaining reasonable device complexity through the use of coupling mechanisms between the paths.
2Use of energy by moving object
If a high Q factor probe is used to maintain near-field energy, then near-field energy efficiency is improved, but energy dissipation time becomes unacceptably long
Solution Approach 1:
The patent introduces a switched circuit that is pre-configured to rapidly dissipate energy stored in the probe after transmission. The switch is positioned and configured in advance to quickly discharge the high Q factor probe following pulse transmission, enabling the probe to maintain high near-field energy efficiency during operation while rapidly dissipating energy when needed.
3Duration of action of moving object
If a switched circuit is used to increase energy dissipation speed, then energy dissipation time is reduced, but stress on switch and circuit components becomes unacceptably high
Solution Approach 1:
The patent introduces a tuned quarter wave-length section as an intermediary element between the transmit and receive circuits. This section provides the desired isolation between transmit and receive signals without requiring the switch and switched circuit to handle excessive voltages and currents, thereby reducing component stress while maintaining effective energy dissipation.
4Measurement precision
If transmit and receive circuits are closely coupled to improve sensitivity, then receive sensitivity is improved, but environmental noise interference increases
Solution Approach 1:
The patent segments the antenna system into separate conductive paths for transmit and receive functions, with the receive circuit coupled to the first conductive path and the transmit circuit coupled to the second conductive path. This segmentation provides electrical isolation that reduces environmental noise interference while maintaining receive sensitivity through optimized coupling mechanisms.
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 dissipates energy stored in the sensor's circuitry after transmission, reducing stress on components and enhancing the sensor's ability to differentiate between strong transmit pulses and weak receive signals, while maintaining low far-field radiation and high near-field energy efficiency.
Implementation Method 1
The transmit matching network may include a plurality of capacitors coupled in parallel between the first and second port and, for each of one or more of the plurality of capacitors, a pair of crossed diodes coupled in series with the capacitor
Implementation Method 2
The receive circuitry can be include a third port coupled to the first conductive path, a fourth port coupled to a low-noise amplifier, and a receive matching/suppression network coupled between the third and fourth ports
Implementation Method 3
the receive matching/suppression network configured to dissipate residual energy within the receive circuitry resulting from transmission of the pulse
Implementation Method 4
an antenna system, transmit circuitry configured to transmit pulses via the antenna system
Implementation Method 5
a fourth port coupled to a low-noise amplifier
Data Source
AI summary
In some embodiments, a near-field sensor comprises an antenna system, transmit circuitry configured to transmit pulses via the antenna system, and receive circuitry configured to receive interrogation signals in response to transmitted pulses. The antenna system can include a first conductive path having one or more loops coupled together, and a second conductive path having one or more loops coupled together, wherein the first and second conductive path are electrically isolated from each other within the antenna system. The transmit circuitry can include a matching network to dissipate energy stored in the transmit circuitry following transmission of a pulse. The receive circuitry can include a suppression network configured to dissipate residual energy within the receive circuitry resulting from transmission of the pulse.