Low-Frequency Wireless Sensor for Absorbing Materials
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Solution Overview
Problem
Sensing environmental conditions within electromagnetic-absorbing materials, such as soil or concrete, is challenging due to issues like inadequate communication range, unreliable operation due to changing electromagnetic characteristics, large equipment sizes, and high power consumption, particularly in agricultural applications where wired connections are impractical.
Innovation Solution
A system comprising an environmental sensor, a modulator, and a switch-mode amplifier powered by a self-contained power supply, using a multi-turn coil with a diameter of less than 0.3 meters to transmit data encoded onto a carrier frequency between 9 kHz and 1705 kHz, minimizing current and voltage during switching transients and forming a frequency-dependent load network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless connections are used to transmit data from sensors embedded in electromagnetic-absorbing materials, then wired connection problems (damage, vandalism, appearance) are avoided, but communication range is inadequate due to attenuation of propagating electromagnetic waves
Solution Approach 1:
The patent changes the operating frequency parameter to very low frequencies (9 kHz to 1705 kHz) where electromagnetic wave attenuation in electromagnetic-absorbing materials is significantly reduced, thereby extending communication range while maintaining wireless operation
Solution Approach 2:
The patent transitions from high-frequency electromagnetic wave propagation to low-frequency magnetic field coupling, effectively changing the dimension of electromagnetic interaction to overcome material attenuation
2Ease of operation
If conventional wireless equipment is used, then wireless operation is achieved, but equipment and antenna sizes are large and incompatible with easy installation and removal of buried sensors
Solution Approach 1:
By operating at very low frequencies, the patent enables the use of small multi-turn coils instead of large conventional antennas, as the wavelength and required antenna dimensions are inversely proportional to frequency
Solution Approach 2:
The wireless transmission function is segmented into a small transmit coil integrated with the sensor unit, allowing independent deployment and removal without large external antenna infrastructure
3Ease of operation
If wireless transmission is implemented, then wired connection issues are resolved, but power consumption is excessive and incompatible with long-term or battery-powered operation
Solution Approach 1:
The patent employs periodic transmission bursts rather than continuous transmission, allowing the sensor to remain in low-power sleep mode between transmissions and significantly reducing overall power consumption
Solution Approach 2:
By using very low frequency operation with small coils, the patent reduces the power required for magnetic field generation compared to conventional high-frequency wireless systems
4Measurement precision
If sensors are buried in electromagnetic-absorbing materials, then environmental monitoring is achieved, but electromagnetic characteristics of the material change and cause unreliable operation
Solution Approach 1:
The patent changes the operating frequency to very low ranges where the electromagnetic characteristics of soil, concrete, and water have minimal impact on signal propagation, ensuring reliable operation despite material variations
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
Enables reliable and efficient data transmission from within electromagnetic-absorbing materials, overcoming the challenges of communication range and power consumption, while being compact and suitable for long-term operation.
Implementation Method 1
The modulator may encode data from the sensor onto a carrier having a carrier frequency between about 9 kHz and about 1705 kHz
Implementation Method 2
The switch-mode amplifier may amplify the carrier which may then be transmitted via a multi-turn coil
Implementation Method 3
The multi-turn coil may have a reactance at the carrier frequency that may form a part of a frequency-dependent load network coupled to the amplifier
Data Source
AI summary
Systems and methods for obtaining telemetry environmental readings from within an electromagnetic-absorbing material are disclosed herein. The system may include a self-contained power source powering a switch-mode amplifier to drive a multi-turn coil to be driven with a low-frequency carrier.