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Showing papers by "Jianqing Wang published in 2015"


Journal ArticleDOI
TL;DR: In this article, an in-body transceiver at around 30 MHz employs impulse radio (IR) technology with multi-pulse position modulation (MPPM) scheme for real-time image/video transmission in implant body area networks.
Abstract: For real-time image/video transmission in implant body area networks, we have developed an in-body transceiver at around 30 MHz. The transceiver employs impulse radio (IR) technology with multi-pulse position modulation (MPPM) scheme. The transmit antenna was realized in a dimension of 1 $\times$ 2 cm by forming the radiation elements on a flexible magnetic sheet. Experimental results in a biological-equivalent liquid phantom have demonstrated a bit error rate smaller than $10^{-3}$ in a depth of 26 cm with a data rate at least 1.25 Mbps.

25 citations


Journal ArticleDOI
TL;DR: Data indicate no adverse effects of long-term RF-EMF exposure on immune-like T cell populations, T cell activation, or Th1/Th2 balance in developing rats, although significant transcriptional effects were observed.
Abstract: With the widespread use of radio-frequency devices, it is increasingly important to understand the biological effects of the associated electromagnetic fields. Thus, we investigated the effects of radio-frequency electromagnetic fields (RF-EMF) on T cell responses during development due to the lack of science-based evidence for RF-EMF effects on developmental immune systems. Sprague Dawley (SD) rats were exposed to 2.14-GHz wideband code division multiple-access (W-CDMA) RF signals at a whole-body specific absorption rate (SAR) of 0.2 W/kg. Exposures were performed for a total of 9 weeks spanning in utero development, lactation and the juvenile period. Rats were continuously exposed to RF-EMF for 20 h/day, 7 days/week. Comparisons of control and exposed rats using flow cytometry revealed no changes in the numbers of CD4/CD8 T cells, activated T cells or regulatory T cells among peripheral blood cells, splenocytes and thymocytes. Expression levels of 16 genes that regulate the immunological Th1/Th2 paradigm were analyzed using real-time PCR in the spleen and thymus tissues of control and RF-EMF–exposed rats. Although only the Il5 gene was significantly regulated in spleen tissues, Il4, Il5 and Il23a genes were significantly upregulated in thymus tissues following exposure to RF-EMF. However, ELISAs showed no changes in serum IL-4 protein concentrations. These data indicate no adverse effects of long-term RF-EMF exposure on immune-like T cell populations, T cell activation, or Th1/Th2 balance in developing rats, although significant transcriptional effects were observed.

22 citations



Journal ArticleDOI
TL;DR: In this paper, three different numerical techniques have been developed for dosimetry of small animals exposed to EM fields inside an RC at microwave frequencies, and the results obtained from each numerical technique were discussed.
Abstract: Reverberation chamber (RC) has been recently developed and used in bio-electromagnetic (EM) field research for investigation of possible adverse health effect of EM waves to human body. Concerning the use of an RC as an exposure device, accurate dosimetry or quantification of EM energy absorbed in exposed animals inside an RC is actually of importance. However, the dosimetry of animals inside an RC is one of challenging problems due to its size and complex behavior of EM fields inside the chamber. This paper is dedicated to the demonstration of three different numerical techniques developed for dosimetry of small animals exposed to EM fields inside an RC at microwave frequencies. First we briefly review procedures of each numerical method and clarify its advantages, disadvantages, and range of applications. Then we demonstrated their validity by either experiments or cross-verification. Finally we discuss the results obtained from each numerical technique.

9 citations



Journal ArticleDOI
TL;DR: In this article, the authors developed an ultra-wideband (UWB) planar loop antenna for implant communication, and confirmed its usefulness by comparing its designed and measured reflection and transmission characteristics.
Abstract: In this study, the authors developed an ultra-wideband (UWB) planar loop antenna for implant communication, and confirmed its usefulness by comparing its designed and measured reflection and transmission characteristics. With the planar loop antenna as the implant transmitting antenna, then they calculated the implant path loss and specific absorption rate (SAR) using the finite difference time domain method together with an anatomical human body numerical model. Moreover, through a link budget analysis based on the calculated path loss with selection diversity, they derived the transmitting power required to achieve a specific bit error rate performance, and clarified the corresponding local SAR with respect to the international safety limits. As a result, the UWB implant communication is found to be feasible at a data rate as high as 40 Mbps under the SAR safety limits.

7 citations



Proceedings ArticleDOI
24 Mar 2015
TL;DR: The proposed TOA-based method for joint location/relative permittivity estimation can achieve not only better localization accuracy than that of the RSSI-based localization but also accurate averaged relative permittivities estimation.
Abstract: A wireless capsule endoscope (WCE) is a promising medical device for diagnosis of digestive organs, which takes pictures inside digestive organs, such as large and small intestines and transmits them through implant wireless communications. In a realistic WCE scenario, it is important to precisely estimate the WCE location. Generally, the superiority of TOA-based localization over RSSI-based localization has been pointed out in many papers in wireless communication systems. However, because the propagation speed inside of a human body varies due to the influence of its biological tissues (namely, the relative permittivity of human tissues), the realization of precise TOA-based localization needs to accurately estimate the propagation velocity of implant communication signals. So, in this paper, we propose a TOA-based method for joint location/relative permittivity estimation, and then compare the performances between TOA- and RSSI-based WCE location estimation methods. Our computer simulation results reveal that, the TOA-based localization with accurate relative permittivity information outperforms the RSSI-based localization in terms of the localization accuracy, whereas the RSSI-based localization is advantageous if accurate relative permittivity is not obtained. Additionally, the proposed TOA-based localization can achieve not only better localization accuracy than that of the RSSI-based localization but also accurate averaged relative permittivity estimation.

6 citations


Proceedings ArticleDOI
01 Nov 2015
TL;DR: In this article, the propagation characteristics on a car body surface for the electric field communication and 2.4 GHz wireless communication were numerically calculated, and it was shown that the former is more effective to pass through a slit hole in a lower path loss.
Abstract: Quasi-electrostatic field on car body surface is considered to be more useful as an in-vehicle communication means, compared with wireless communication and wire harness communication. In this study, we numerically calculated the propagation characteristics on a car body surface for the electric field communication and 2.4 GHz wireless communication, respectively, and showed that the former is more effective to pass through a slit hole in a lower path loss. Moreover, we also expressed the transmitting electrode, the car body and the receiving electrode with an equivalent circuit in view of their near-field coupling characteristic, and yielded the matching impedances of the transmitting and receiving electrodes in order to improve transmission effectiveness.

4 citations


Proceedings ArticleDOI
24 Mar 2015
TL;DR: This paper investigates the performances of the developed transmit diversity antenna, including the S-parameters and correlation coefficient between each polarization, based on a finite difference time domain (FDTD) method and evaluates the bit error rate (BER) performance for the transmit polarization diversity.
Abstract: An ultra wideband impulse radio (UWB-IR) technology is a potential candidate for implant body area networks (BANs), where wireless communications are established between inside and outside of a human body. The UWB-IR technology can accomplish low power consumption and high data rate with an extremely short pulse. However, due to its high frequencies, UWB-IR signals suffer from quite large attenuation in the implant communication link, which makes it difficult to achieve reliable communications. For achieving reliable communication, it is well known that a spatial diversity technique is efficient without any frequency extension. In the related works, several spatial receive diversity techniques for the implant communications have been so far discussed. In contrast, the diversity technique at transmitter side has been rarely discussed because of difficulty of the antenna miniaturization. In this paper, we pay attention to the fact that it is possible to further miniaturize the UWB antenna due to its high frequency, so that, we aim to develop a transmit polarization diversity antenna for implant UWB communications. Then, we investigate the performances of the developed transmit diversity antenna, including the S-parameters and correlation coefficient between each polarization, based on a finite difference time domain (FDTD) method. Finally, we evaluate the bit error rate (BER) performance for the transmit polarization diversity. The computer simulation results demonstrate the feasibility and effectiveness of the transmit diversity for the UWB-IR communications.

3 citations


Proceedings ArticleDOI
05 Nov 2015
TL;DR: In this paper, the communication performances of UWB-impulse radio (UWB-IR) and multiband-orthogonal frequency division multiplexing (MB-OFDM) are compared and both modulation schemes for the transmit polarization diversity from the viewpoint of the BER and the required transmit power are evaluated.
Abstract: An ultra wideband (UWB) technology is a potential candidate for implant body area networks (BANs), where wireless communications are established between inside and outside of a human body. The UWB can accomplish higher data rate than the other frequency band for the implant communication. However, due to its high frequencies, the UWB signals suffer from quite large attenuation in the implant communication link, which makes it difficult to achieve reliable communications. For achieving reliable communication, it is well known that a spatial diversity technique is efficient without any frequency extension. In our previous works, we developed a transmit polarization diversity antenna for the UWB implant communication. However, optimal UWB modulation scheme for transmit diversity were rarely discussed. In this paper, in order to investigate the optimal UWB modulation schemes for implant communication with transmit diversity, we compare the communication performances of UWB-impulse radio (UWB-IR) and multiband-orthogonal frequency division multiplexing (MB-OFDM). For this purpose, we first analyze the propagation characteristics in the implant UWB channel , which ranges from 3.4 GHz to 4.8 GHz, using a finite difference time domain (FDTD) numerical analysis technique. Then, we evaluate and discuss the communication performances of both modulation schemes for the transmit polarization diversity from the viewpoint of the BER and the required transmit power.

Proceedings ArticleDOI
01 Nov 2015
TL;DR: In this article, the authors measured EM noise power at 2.4 GHz and 30 MHz bands for indirect ESD immunity testing according to the IEC 61000-4-2 standard, and derived a statistical ESD noise model based on the measurement results.
Abstract: Wireless body area networks (BANs) are attracting much attention to healthcare and medical applications. Electrostatic discharge (ESD) may be a major electromagnetic (EM) noise source to interfere the wireless communication performance. In this study, we measured EM noise power at 2.4 GHz and 30 MHz bands for indirect ESD immunity testing according to the IEC 61000-4-2 standard, and derived a statistical ESD noise model based on the measurement results. The ESD noise power was found to follow lognormal distribution.

Proceedings ArticleDOI
06 Aug 2015
TL;DR: A two-step approach is proposed to evaluate electromagnetic interference (EMI) with a wearable electrocardiogram (ECG) sensor that combines a quasi-static electromagnetic field analysis and an electric circuit analysis and is applied to the EMI analysis at frequencies below 1 MHz to demonstrate its usefulness.
Abstract: In this study, we propose a two-step approach to evaluate electromagnetic interference (EMI) with a wearable electrocardiogram (ECG) sensor. The two-step approach combines a quasi-static electromagnetic (EM) field analysis and an electric circuit analysis, and is applied to the EMI analysis at frequencies below 1 MHz for our developed wearable ECG to demonstrate its usefulness. The quasi-static EM field analysis gives the common mode voltage coupled from the incident EM field at the ECG sensing electrodes, and the electric circuit analysis quantifies a differential mode voltage at the differential amplifier output of the ECG detection circuit. The differential mode voltage has been shown to come from a conversion from the common mode voltage due to an unbalance between the contact impedances of the two sensing electrodes. It may achieve nearly 0.6 V at the differential amplifier output under 10-V/m plane-wave incident electric field, and completely mask the ECG signal. It is essential to reduce the unbalance as much as possible to not cause a significant interference voltage in the amplified ECG signal.

Journal ArticleDOI
TL;DR: This special issue includes seven interesting articles that tackle some of the existing challenges and design issues related to the use of RF and Communication Technologies for wireless implants.
Abstract: THIS special issue includes seven interesting articles that tackle some of the existing challenges and design issues related to the use of RF and Communication Technologies for wireless implants. An in-body medical device is a miniature device that is inserted in the human body to collect physiological signals and images or to act like a prosthetic device restoring certain body functions. In order for these devices to communicate with the external world, radio frequency (RF) wireless technologies are often used to maintain their operation for a longer period of time. This is achieved by integrating wireless communication technologies within these devices. In some situations, a body worn device is used to receive the medical information from the devices in the human body and then transmit to remote stations for remote medical monitoring.

Proceedings ArticleDOI
28 Sep 2015
TL;DR: In this paper, a particle filter algorithm was used to estimate the moving distance and heading direction of a capsule endoscope (WCE) system only with RSSI measurement data, which can be obtained as a fundamental function of wireless communications.
Abstract: In this paper, we propose a simultaneous moving distance and heading direction estimation method for wireless capsule endoscope (WCE) system only with RSSI measurement data, which can be obtained as a fundamental function of wireless communications. This paper first focuses on an RSSI-based WCE location tracking method with a particle filter algorithm. Then, in order to accurately estimate the moving distance and heading direction, the proposed method detects the waypoints (pass points) based on the time-series estimated WCE location information, on which the WCE moving in gastrointestinal tract. Consequently, both estimation can be realized with connecting the estimated waypoints. From our computer simulation results, the proposed method can achieve good estimation performances of the moving distance and heading direction with the accuracies of several centimeters and several degrees, respectively, without specific additional sensor devices.


Journal ArticleDOI
TL;DR: In this article, the whole-body average specific absorption rate (WBA-SAR) in humans for simultaneous exposure to multiple radio frequencies (RFs) was calculated in real environments.
Abstract: SUMMARY There are few published papers on the whole-body average specific absorption rates (WBA-SARs) in humans for simultaneous exposure to multiple radio frequencies (RFs). In order to evaluate human safety of radiowaves in real environments, in this paper we calculate the WBA-SARs in models of a pregnant woman and 3-year-old child for multiple RF exposure, using measured results on electric field intensities from multiple base station antennas installed for cellular phones with four different radiowave frequencies in an underground shopping mall and with five radiowave frequencies in the neighborhood of an elementary school. The Japan Ministry of Internal Affairs and Communications officially reported these data in 2008. Statistical analyses show that the squared sum ratio of the measured electric field to the corresponding Japanese guideline for the general public is smaller than one-hundredth and one-thousand at most in the underground shopping mall and elementary school areas, respectively. As a result, we found that the WBA-SARs in the pregnant woman and 3-year-old child models calculated at each of the frequencies for base station antennas in both areas are significantly lower than the The International Commission on Non-Ionizing Radiation Protection (ICNIRP) basic restriction (0.08 W/kg) for the general public, and that the sum of the WBA-SARs never exceeds one-hundredth of 0.08 W/kg for simultaneous exposure to multiple RF.

Proceedings ArticleDOI
28 Sep 2015
TL;DR: A moving average algorithm was employed to reduce the noises produced in the received ECG signals due to the car's movement to confirm a real-time ECG transmission of driver in the moving car with a reasonable accuracy.
Abstract: In this study, we developed a wearable electrocardiogram (ECG) sensor with human body communication (HBC) technology for vital data transmission in a car. The ECG signals were modulated with wideband pulse signals between 10 and 60 MHz based on an impulse radio (IR) scheme, which provides a data rate as high as 1.25 Mbps. To apply the HBC-based wearable ECG in a moving car, we employed a moving average algorithm to reduce the noises produced in the received ECG signals due to the car's movement. As a result, we confirmed a real-time ECG transmission of driver in the moving car with a reasonable accuracy.

14 Dec 2015
TL;DR: A RSSI-based WCE location tracking method with a particle filter algorithm that can achieve good estimation performances of the moving distance and heading direction with the accuracies of several centimeters and several degrees, respectively, without specific additional sensor devices.
Abstract: In this paper, we propose a simultaneous moving distance and heading direction estimation method for wireless capsule endoscope (WCE) system only with RSSI measurement data, which can be obtained as a fundamental function of wireless communications. This paper first focuses on an RSSI-based WCE location tracking method with a particle filter algorithm. Then, in order to accurately estimate the moving distance and heading direction, the proposed method detects the waypoints (pass points) based on the time-series estimated WCE location information, on which the WCE moving in gastrointestinal tract. Consequently, both estimation can be realized with connecting the estimated waypoints. From our computer simulation results, the proposed method can achieve good estimation performances of the moving distance and heading direction with the accuracies of several centimeters and several degrees, respectively, without specific additional sensor devices.