Radio ranging with ultrahigh resolution using a harmonic radio-frequency identification system

Hui, Xiaonan; Kan, Edwin C.

doi:10.1038/s41928-019-0219-0

Cited by 39 publications

(19 citation statements)

References 38 publications

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“…Simultaneously, as the readers transmit only the fundamental frequency, the reader-to-reader interference will be greatly reduced. Additionally, as the harmonic frequency reduces the operating wavelength, the localization accuracy is significantly enhanced [ 37 ]. Two different cases of harmonic phase based localization and sensing are shown in Figure 3 .…”

Section: Drawback Of Conventional Rfidmentioning

confidence: 99%

“…In [ 35 , 37 , 76 ], ultra-high resolution in the range of millimeter to micrometer was reported using broadband harmonic RF ranging. In [ 76 ], a second harmonic backscattering solution was proposed with millimeter scale accuracy, even effective against body motion interference.…”

Section: Applicationsmentioning

confidence: 99%

“…In [ 76 ], a second harmonic backscattering solution was proposed with millimeter scale accuracy, even effective against body motion interference. In [ 37 ], a 1 GHz harmonic RFID system was used to demonstrate a ranging resolution of less than 50 micrometers with a sampling rate of greater than 1 kHz.…”

Section: Applicationsmentioning

confidence: 99%

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Recent Advances and Applications of Passive Harmonic RFID Systems: A Review

2021

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Harmonic Radio Frequency Identification (RFID) systems have attracted significant interest over the last decade as it provides many benefits over the conventional RFID systems. Harmonic RFID is desired over conventional RFID systems due to reduced self-jamming, location accuracy from dual frequency, and higher phase noise immunity. In a harmonic RFID system, the tag receives instructions from the reader at an RF carrier frequency and replies back at the harmonic of the RF frequency. A nonlinear element consuming very low power at the tag is required to generate the harmonic carrier for the battery-less system. In this review article, a detailed contrast between conventional and harmonic RFID systems is presented. This is followed by different circuit design techniques to generate harmonics and integration techniques to form a fully operable passive harmonic RFID tag. Also, a wide range of applications, especially sensor integration with harmonic RFID’s, along with the future trends are presented.

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Section: Drawback Of Conventional Rfidmentioning

confidence: 99%

Section: Applicationsmentioning

confidence: 99%

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Recent Advances and Applications of Passive Harmonic RFID Systems: A Review

2021

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“…where 𝑧 = 𝛼 2 2 − 2. For any 𝑖 > 2, 𝑓 𝛼 𝑖 (𝛼 𝑖 ) can subsequently be found from (47) by applying numerical methods 3 . Fig.…”

Section: B Phase Adjustmentmentioning

confidence: 99%

Harmonic Radar with Adaptively Phase-Coherent Auxiliary Transmitters

Lavrenko,

Cavers,

Woodward

2021

Preprint

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In harmonic radar (HR), the radio frequency transmitter illuminates a nonlinear target (the tag), causing the return signal to consist of harmonics at multiples of the transmitted carrier frequency. Of them, the second harmonic is usually the strongest and the one to which the receiver is tuned. This frequency difference distinguishes the tag reflection from environmental clutter, which remains at the uplink (transmitter to tag) frequency. However, the passive nature of HR tags severely limits the reflected power, and therefore the range of the downlink (tag to receiver) path. We propose to increase the range and/or signal to noise ratio (SNR) by novel restructuring at the physical and signal levels. For this, we accompany the original transmitter with auxiliary transmitters able to send simple tones that are synchronized to arrive at the tag in phase, and we design the receiver to detect an intermodulation component. The resulting range and SNR are much greater than those of the original, conventional HR system, and greater even than if the original system were to transmit with power equal to the aggregate power of our new system. Achieving mutually coherent, i.e., in phase, arrival of the tones at the tag is the focus of the present paper. We provide a system framework that models the tag and the uplink and downlink, then present the adaptive phase coherence algorithm and analyze the probabilistic growth of the output signal power. We also account for the effects of frequency shifts due to transmitter mobility and the frequency offset errors in the transmitter local oscillators.

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“…The other three ports (Po2 to Po4) are similarly configured with Tx2 and Rx2 to Po2 in SDR1, Tx3 and Rx3 to Po3 in SDR2, and Tx4 and Rx4 to Po4 in SDR2. The RF signal at each Tx can be multiplexed with time-division multiple access (TDMA) [19], code division multiple access (CDMA) [20], [21] or, in the case of this work, frequency division multiple access (FDMA) [17], [22]. The carrier frequency is 1.82 GHz with 0.71 MHz, 1.22 MHz, 1.71 MHz and 2.33 MHz baseband offsets for Tx1 -Tx4, respectively.…”

Section: The Multi-point Ncs System Setupmentioning

confidence: 99%

Multi-Point Near-Field RF Sensing of Blood Pressures and Heartbeat Dynamics

2020

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Systolic and diastolic blood pressure estimation using arm-cuff monitors is one of the most common cardiovascular evaluation criteria in healthcare today, however these measures lack critical heartbeat and pressure dynamics. Pulse-transit time can be used as an alternative for arm-cuff monitors, but gives only one parameter for two pressure quantities. Ultrasound, computed tomography scan, and magnetic resonance imaging can retrieve geometrical features of the heart, but cannot directly estimate vascular pressures. Here we show a novel radio-frequency heartbeat sensor based on multi-point near-field observation. By comparing to synchronized electrocardiogram and auscultation, the multi-point sensor can assess motion and pressure in different parts of the heart following the Wiggers diagram. By applying the Hilbert-Huang frequencytime transform, the central blood pressure can be derived from the vascular vibration characteristics as continuous transients, including during the pulmonary cycle which is previously inaccessible from branchial measurements. Our scheme can be further extended to a full multiple-input-multiple-output (MIMO) channel arrangement, producing rich content for diagnostic and biometric applications. We employ dynamic time warping analyses to illustrate the sensor's wealth of diversified information across different channels and persons. This new multi-point sensor, which can be worn conveniently over clothing, enables unprecedented monitoring capabilities of detailed central blood pressure transients and heartbeat dynamics under the given measurement instructions for at-home and clinical cardiovascular diagnostics.

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Radio ranging with ultrahigh resolution using a harmonic radio-frequency identification system

Cited by 39 publications

References 38 publications

Recent Advances and Applications of Passive Harmonic RFID Systems: A Review

Recent Advances and Applications of Passive Harmonic RFID Systems: A Review

Harmonic Radar with Adaptively Phase-Coherent Auxiliary Transmitters

Multi-Point Near-Field RF Sensing of Blood Pressures and Heartbeat Dynamics

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