Vital sign detection for handheld communication device using antenna mismatching effect

An, Yong-Jun; Yun, Gi-Ho; Yook, Jong‐Gwan

doi:10.1109/mwsym.2013.6697519

Cited by 12 publications

(5 citation statements)

References 10 publications

(10 reference statements)

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“…The antenna input impedance can be retrieved from the antenna reflection coefficient. The magnitude of the antenna reflection coefficient can be readily measured using a coupler structure, as reported in [22]. The reflection coefficient is determined by magnitudes and phases of the incident wave and the reflected wave.…”

Section: Impedance Detection Circuitmentioning

confidence: 99%

Estimation of Diaper Condition Based on Antenna Impedance Variation Through Rational Function Approximation

Turna

Kim

2020

IEEE Access

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Real-time monitoring of a diaper is a key component in preventing skin rashes and skin eruption in babies. In this paper, we investigate the feasibility of sensing the urine and feces of a baby on a diaper using the input impedance variation of a single on-diaper antenna. As an RF transmitter requires an antenna by default, other sensors are not needed if the antenna also serves as a sensor. We designed a microstrip dipole antenna and located it on a diaper. When a change of medium properties around the antenna occurs due to the presence of urine or feces, the near field is perturbed, causing a variation in antenna impedance. We simulated and measured antenna impedance under diverse diaper conditions. Results showed significant impedance variation depending on diaper condition. The impedance is approximated as a rational function and the diaper condition is classified through investigating the parameter of the rational function. INDEX TERMS Antenna impedance variation, micro-strip antenna, near-field perturbation, pole model, smart diaper.

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Section: Impedance Detection Circuitmentioning

confidence: 99%

Estimation of Diaper Condition Based on Antenna Impedance Variation Through Rational Function Approximation

Turna

Kim

2020

IEEE Access

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“…4. The system is a kind of reflectometer, detecting the magnitude of the reflection coefficient with enhanced sensitivity [23]. When a planar RF resonator is located close to the artery, the reflection coefficient of the resonator is affected by the motion of the artery due to the fluidic nature of the blood.…”

Section: A Flexible Rf Resonatormentioning

confidence: 99%

“…Because the combined signal only has the wrist pulse dependent variant component γ(t) of the reflection coefficient, the combined signal provides much higher sensitivity than the reflected signal itself [23]. In addition, wrist pulses can be detected well by an RF near-field detection system which has a flexible resonator and substrate [24].…”

Section: A Flexible Rf Resonatormentioning

confidence: 99%

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Heart Rate Detection During Sleep Using a Flexible RF Resonator and Injection-Locked PLL Sensor

Kim

Seung-Hun

et al. 2015

IEEE Trans. Biomed. Eng.

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Novel nonintrusive technologies for wrist pulse detection have been developed and proposed as systems for sleep monitoring using three types of radio frequency (RF) sensors. The three types of RF sensors for heart rate measurement on wrist are a flexible RF single resonator, array resonators, and an injection-locked PLL resonator sensor. To verify the performance of the new RF systems, we compared heart rates between presleep time and postsleep onset time. Heart rates of ten subjects were measured using the RF systems during sleep. All three RF devices detected heart rates at 0.2 to 1 mm distance from the skin of the wrist over clothes made of cotton fabric. The wrist pulse signals of a flexible RF single resonator were consistent with the signals obtained by a portable piezoelectric transducer as a reference. Then, we confirmed that the heart rate after sleep onset time significantly decreased compared to before sleep. In conclusion, the RF system can be utilized as a noncontact nonintrusive method for measuring heart rates during sleep.

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“…1. The system proposed in the present work [18], [19] utilizes the magnitude of the antenna reflection coefficient and provides high sensitivity. The proposed system does not require additional signal source and antenna, so that it can be easily realized in RF CMOS IC.…”

mentioning

confidence: 99%

Sensitivity Enhanced Vital Sign Detection Based on Antenna Reflection Coefficient Variation

Yun

Yook

2016

IEEE Trans. Biomed. Circuits Syst.

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This paper presents a vital sign detection sensor based on reflection coefficient variance from an antenna used in wireless communication devices. The near-field effect is estimated by performing 3D full-wave simulations using a dipole antenna and the magnitude variation of the reflection coefficient induced by human thorax movement due to heart and lungs is observed. The results support the possibility of vital sign detection based on the magnitude variation of the reflection coefficient from an antenna, which can be explained as a narrowband modulation scheme. In particular, a sensitivity enhancement method is proposed and analyzed, and experiments are carried out for heartbeat detection using a dipole antenna with the proposed system. Experimental results are compared between the direct detection and sensitivity enhancement detection schemes. FM signal is also applied to confirm that the proposed sensor works properly in conjunction with an existing communication system. The proposed cardiopulmonary detection sensor is implemented with off-the-shelf components at 2.4 GHz and excellent performance is obtained.

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Vital sign detection for handheld communication device using antenna mismatching effect

Cited by 12 publications

References 10 publications

Estimation of Diaper Condition Based on Antenna Impedance Variation Through Rational Function Approximation

Estimation of Diaper Condition Based on Antenna Impedance Variation Through Rational Function Approximation

Heart Rate Detection During Sleep Using a Flexible RF Resonator and Injection-Locked PLL Sensor

Sensitivity Enhanced Vital Sign Detection Based on Antenna Reflection Coefficient Variation

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