Complex-Impedance Dipole Antennas as RFID-Enabled Ice Monitors (original) (raw)

Wireless Ice Detection and Monitoring using Flexible UHF RFID Tags

2021

Owing to its low relative permittivity, very few microwave sensors have been developed for monitoring ice deposition. This paper presents the first use of UHF RFID tags for wireless RF ice sensing applications. Despite its low permittivity, the existence of ice as a superstrate on a planar ultra-thin dipole antenna can lower the resonance frequency of the antenna significantly. The RFID tags, having a measured unloaded range of 9.4 m, were evaluated for remotely detecting the formation of ice in various scenarios and up to 10~m from the reader, as well as monitoring the ice thawing, based on the Relative Signal Strength (RSS) in a phase-free approach. Unlike conventional RSS-based sensing approaches where the tag's read-range is reduced as the RSS decreases in response to the stimulant, the ice superstrate improves the impedance matching of the tags, maintaining a 10 m loaded read-range with over 12 dB ice-sensitivity, in an echoic multi-path environment. The long range and high...

Toward the Optimal Antenna-Based Wireless Sensing Strategy: An Ice Sensing Case Study

IEEE Open Journal of Antennas and Propagation

Remote ice detection has emerged as an application of Radio Frequency (RF) sensors. While antenna-based "RFID" sensing can detect various measurands, antenna-based sensors are not currently designed based on a systematic methodology, and in most cases may have a low sensitivity requiring specialist hardware or broadband interrogation signals, incompatible with spectrum regulations. Here, we develop a systematic methodology for designing an antenna-based sensor, applicable to measurands inducing a dielectric change in the near-field of the antenna. The proposed methodology is applied to designing printable antennas as highly-sensitive sensors for detecting and measuring the thickness of ice, demonstrating best-in-class sensory response compared to more complex antenna designs. Antenna design is investigated systematically for wireless interrogation in the 2.4 GHz band, where it is found that a loop antenna outperforms a dipole owing to its more distributed capacitance. The antenna's realized gain was identified as the optimum parameter-under-test, with "positive" sensing proposed as a method of improving linearity and immunity to interference. The developed loop antenna sensor exhibits resilience to interference and applicability to different real-world deployment environments, demonstrated through over 80% average ice thickness measurement accuracy and at least 5 dB real-time sensitivity to ice deposition.

Towards the Optimal Antenna-Based Wireless Sensing Strategy: An Ice Sensing Case Study

2021

Remote ice detection has emerged as an application of Radio Frequency (RF) sensors. While antenna-based “RFID” sensing can detect various measurands, antenna-based sensors are not currently designed based on a systematic methodology, and in most cases may have a low sensitivity requiring specialist hardware or broadband interrogation signals, incompatible with spectrum regulations. Here, we develop a systematic methodology for designing an antenna-based sensor, applicable to measurands inducing a dielectric change in the near-field of the antenna. The proposed methodology is applied to designing printable antennas as highly-sensitive sensors for detecting and measuring the thickness of ice, demonstrating best-in-class sensory response compared to more complex antenna designs. Antenna design is investigated systematically for wireless interrogation in the 2.4 GHz band, where it is found that a loop antenna outperforms a dipole owing to its more distributed capacitance. The antenna’s ...

Patch antenna sensor for wireless ice and frost detection

Scientific Reports, 2021

A patch antenna sensor with T-shaped slots operating at 2.378 GHz was developed and investigated for wireless ice and frost detection applications. Detection was performed by monitoring the resonant amplitude and resonant frequency of the transmission coefficient between the antenna sensor and a wide band receiver. This sensor was capable of distinguishing between frost, ice, and water with total shifts in resonant frequency of 32 MHz and 36 MHz in the presence of frost and ice, respectively, when compared to the bare sensor. Additionally, the antenna was sensitive to both ice thickness and the surface area covered in ice displaying resonant frequency shifts of 2 MHz and 8 MHz respectively between 80 and 160 μL of ice. By fitting an exponential function to the recorded data, the freezing rate was also extracted. The analysis within this work distinguishes the antenna sensor as a highly accurate and robust method for wireless ice accretion detection and monitoring. This technology ha...

Experimental study of relative permittivity of atmospheric ice

International Journal of Energy, Environment and Economics

Atmospheric icing on onshore and offshore structures is problematic, if we don’t detect and remove it. Despite of various ice detection techniques, capacitor based ice sensing technique is interesting one, as it is based on dielectric property of material. This technique of measuring icing event is simple and cost effective. Based on the dielectric concept, an experimental setup comprised of two rectangular aluminum bars in parallel connected with an LCR meter, thermocouples, data acquisition system and computer was designed at cold room chamber facility of Narvik University College to study the transient response of dielectric constant of ice at different operating atmospheric conditions. Analysis showed that depending on the atmospheric ice type the capacitance varies due to the variation in temperature.

Development of Impedance-Based Miniaturized Wireless Water Ice Sensor for Future Planetary Applications

IEEE Transactions on Instrumentation and Measurement, 2012

Keeping in view the future in situ space applications, to study planetary surface science, we have designed and developed an impedance-based extremely compact wireless sensor node to infer the presence of water/ice in a soil sample and reported in this paper. Although reflectometry-based soil moisture sensors are available commercially, they have slightly longer probe, needing more volume, from the payload point of view. The reported wireless impedance sensor reproduced in space-qualified form can be useful to measure the permittivity of lunar regolith and infer the presence of water ice. It works in the frequency domain with capability to sweep the frequency in a given measurement range. The sensor does not necessarily have long probe, and it needs only electrical contact with the soil surface, thus eliminating extra energy for insertion by the rover on the lunar surface, in one of its possible space applications. The sensor has been made to operate in wireless mode, which is a basic need in any space applications. The data are transmitted at 2.4 GHz to the aggregator. We have tested sand-type terrestrial soil and lunar soil simulant JSC-1A. To verify the performance of the sensor, we have also tested Milli-Q water. All these experimental results are reported in this paper. Results of Milli-Q water, whose permittivity is known, agree with those reported in the literature, verifying excellent performance of the sensor. Thus, the sensor can be very useful for space applications, where size and weight are critical issues. A wireless impedance sensor can also be quite useful for terrestrial applications, for example, in agriculture, and also in other impedance-based applications.

Dielectric based sensing of atmospheric ice

AIP Conference Proceedings

Atmospheric ice is a naturally occurring mixture with lots of variations. It doesn’t only bind the chemistry of water, but also its physics. The variations of this complex mixture are directly associated with the surrounding dynamics. In this paper we are mainly concerned about the variations in the electrical properties of atmospheric ice due to variation in the surrounding temperature, conductivities, volumetric contents and relaxation time. All these variations are conveniently measured using the permittivity/dielectric sensing principles. Also these calculations can later be utilized to formulate the atmospheric ice type, icing rate and ice thickness.

Electromagnetism based atmospheric ice sensing technique - A conceptual review

The International Journal of Multiphysics, 2012

Electromagnetic and vibrational properties of ice can be used to measure certain parameters such as ice thickness, type and icing rate. In this paper we present a review of the dielectric based measurement techniques for matter and the dielectric/spectroscopic properties of ice. Atmospheric Ice is a complex material with a variable dielectric constant, but precise calculation of this constant may form the basis for measurement of its other properties such as thickness and strength using some electromagnetic methods. Using time domain or frequency domain spectroscopic techniques, by measuring both the reflection and transmission characteristics of atmospheric ice in a particular frequency range, the desired parameters can be determined.

Wireless Measurement of RFID IC Impedance

IEEE Transactions on Instrumentation and Measurement, 2000

Accurate knowledge of the input impedance of a radio-frequency identification (RFID) integrated circuit (IC) at its wake-up power is valuable as it enables the design of a performance-optimized tag for a specific IC. However, since the IC impedance is power dependent, few methods exist to measure it without advanced equipment. We propose and demonstrate a wireless method, based on electromagnetic simulation and threshold power measurement, applicable to fully assembled RFID tags, to determine the mounted IC's input impedance in the absorbing state, including any parasitics arising from the packaging and the antenna-IC connection. The proposed method can be extended to measure the IC's input impedance in the modulating state as well. Index Terms-Error analysis, impedance measurement, microwave antennas, microwave radio communication, Monte Carlo methods. I. INTRODUCTION R ADIO-FREQUENCY identification (RFID) system is a wireless automatic identification system, where objects are tagged with transponders, consisting of an antenna and an integrated circuit (IC). Passive RFID tags scavenge energy for their operation from an incident electromagnetic field, set by the reader unit. When the on-tag IC receives sufficient power to enable its full functionality, it is able to demodulate commands from the reader and to modulate the tag's response to the antenna-mode backscattered field by switching its input impedance between two values. Most importantly, the IC's memory contains a unique identification code providing an identity for the tagged object. Battery-assisted passive tags are equipped with an on-tag battery to provide energy for the IC, but they also backscatter their response to the reader only under the reader's interrogation, as do the passive tags. Active RFID tags, on the other hand, are capable of independent transmission, and they can act effectively as radio transmitters [1].

Review of Capacitive Atmospheric Icing Sensors

The application of capacitive sensing technique is widely distributed in different physical domains primarily because of the diversity in dielectric permittivity and due to its minimum loading error and inertial effects. Atmospheric ice is a complex mixture of water, ice and air which is reflected in its complex dielectric constant. There are many existing atmospheric icing sensors but only few are based on their complex dielectric permittivity measurements. This technique is very suitable because the capacitive variation in this mixture is due to the reorientation of water dipole in the electromagnetic radiation’s oscillating field. Depending on the frequency, the dipole may move in time to the field, lag behind it or remain apparently unaffected. This variation is clearly reflected on the cole cole diagram which is a measure of the relaxation frequency. This paper is a review of existing capacitive atmospheric icing sensing techniques and some recommendations for new atmospheric i...