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The loss characteristics of radio propagation in 920-MHz band in a farm were investigated. An experiment was carried out in a mulberry field of the area of 50 m × 50 m in order to obtain fundamental data of the path loss in the field. Received Signal Strength Indicator (RSSI) according to the distance between the transmitting antenna (Tx) and the receiving antenna (Rx) was investigated. Tx was placed...
Near-field coupling communication (NFCC) is a technology that uses the surface of the human body as a transmission path in the MHz band. It is necessary to assess the signal loss on the body to ensure stable NFCC links. The dependence of signal loss on different positions on the body was measured with a transmitter powered by a battery and an electrically isolated probe as a receiver. The electric-field...
The change of the radio wave propagation loss in 920-MHz band was examined as bushes in a farm grew higher. Received Signal Strength Indicator (RSSI) was measured as a function of the distance between the transmitting antenna (Tx) and the receiving antenna (Rx) in a 50 × 50 m mulberry field. Tx and Rx were placed at a height of 1.5 m. Moreover, the horizontal and vertical polarizations were measured...
Data centers face problems with concerns about instability in power supply systems caused by sharp changes in load such as power consumption by servers and diversification patterns in their power consumption. We have investigated a method of switching power flows by using power semiconductors via economical 920-MHz band wireless communication to control rises and falls in power in real time as a solution...
A new type of passive circularly polarized beam antenna with high radiation efficiency and polarization rotation switching capability is proposed, based on phase-nonreciprocal metamaterial. The proposed design implements circular polarization rotation switching by means of an external dc magnetic system non-interfering with the signal path. The planar antenna with a working area of less than 6 cm...
Current problems related to the power grid in Japan include the large-scale introduction of natural energy resources and summertime peak power cutting and shifting. Data centers face similar problems with concern for instability in the power supply system caused by sharp changes in load such as server power consumption and diversification in server power consumption patterns. As a solution to such...
Near-Field Coupling Communication (NFCC) is a technology that uses the surface of the human body as a data transmission path in the MHz-Band. It is important to assess the loss of signal propagation on the human body to design stable NFCC links. We measured the signal propagation characteristics on a phantom which is equivalent to the human body with an electrically isolated probe and a transmitter...
This paper describes noise transmission analysis for near-field intra-body communication systems based on parasitic capacitance measurement around the human body. Intra-body communication systems use the human body as the signal transmission medium. In communication systems of this type, the transmission line’s impedance balance between the signal line and the ground line is extremely degraded by...
Near-field coupling communication (NFCC) is a technology that uses the surface of the human body as a data transmission path in the MHz-Band. It is important to assess the loss of signal propagation on the human body to design stable NFCC links. We measured the signal propagation characteristics on and above a phantom which is equivalent to the human body with a transmitter powered by a battery and...
In this paper, we describe an induced signal measurement on the human body for developing a high-performance transceiver of an intra-body communication system. It is important to isolate awearable transceiver from an electrical instrument for precise measurement. We have developed a probe system using an optical isolation method including a laser diode, photo-diode, and optical fiber. The probe system...
We developed a near-field coupling communication (NFCC) technology that uses the surface of the human body as a data transmission path in the MHz band. It is important to assess the loss of signal propagation on the human body to design a “touch and connect” form of stable NFCC links. We measured the signal propagation characteristics on a phantom equivalent to the human body with an electrically...
Radiation beam squinting phenomenon affects nonreciprocal CRLH leaky-wave antennas in the same way as conventional phased arrays. Unlike in phased arrays, attempts to eliminate beam squinting in metamaterial leaky-wave antennas face the problem of reduced radiation angles. In this work, we propose a new design of nonreciprocal metamaterial intended for the non-squinting antenna with enhanced radiation...
The resonant-type nonreciprocal CRLH leaky-wave antenna design provides gain and directivity enhancement, as well as lower beam squinting, compared to conventional leaky-wave antennas. However a method for complete beam-squinting elimination was not available at the moment. It is known that the beam squinting is related to dispersion of magnitude of nonreciprocity in phase constant in nonreciprocal...
This paper describes an electrically isolated system for measuring signals in near-field coupling communication (NFCC) that uses the surface of the human body as a path to transmit signals in the MHz-band. It is important to assess the path loss of signal propagation near and on the human body to design a stable and reliable NFCC network. We developed an electrically isolated probe consisting of an...
This paper describes noise analysis for near-field intra-body communication, in which the human body is the transmission medium. In this type of communication system, the transmission line's impedance balance between the signal and the ground line is extremely degraded. Such a system is affected by large common-mode noise from various kinds of electronic equipment. Impedance balance deteriorates as...
Isotropic three-dimensional composite right/left handed (CRLH) metamaterial structure is proposed and designed. It is composed of conductive jungle gym structure and dielectric spheres with high dielectric constant. By adjusting the configuration parameters appropriately, balanced CRLH transmission structures are designed in the numerical simulation. The numerical results show that the wavenumber...
We propose a technology for megahertz-band near field coupling communication using a communication path between a transceiver (TRX) on the surface of the human body (Wearable TRX) and a TRX embedded in the environment (Embedded TRX). We embedded a transceiver (In-body TRX) in a phantom that had the same electrical properties as those of the human body to apply this technology to the healthcare and...
Polarization-rotating zeroth-order-resonator (ZOR) antenna with voltage-controlled reflectors at both ends is proposed and experimentally demonstrated. The resonator antenna is composed of a microstrip-line-based CRLH transmission line with reactance loads at both ends. The resonant condition is satisfied when the impedance of one load is the complex conjugate of another. Voltage-controlled reactance...
Eigenmode analysis combining elements of field theory and transmission line model was applied to ferrite-embedded phase-nonreciprocal transmission line metamaterial. The dispersion of dominant TE-modes is described analytically from magnetic properties of the ferrite and asymmetry of the structure. The results were proved with full-wave numerical simulation and experiment.
We propose a technology for megahertz-band near field coupling communication using a communication path between a transceiver (TRX) on the surface of the human body (Wearable TRX) and a TRX embedded in the environment (Embedded TRX). We embedded a transceiver (In-body TRX) in a phantom that had the same electrical properties as the human body to apply this technology to the healthcare and medical...
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