Masaki Ishida

MHz-band RF signal propagation characteristics on human body for intra-body communication

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 driven by a battery. In addition, we evaluated the signal loss characteristics with a high frequency structure simulator. We found dependencies of signal loss on distance in both the experiments and simulations and also revealed the correlation between the distance of the phantom from floor ground and the dependency of signal loss on a reclining phantom.

Signal interference analysis model in near-field coupling communication

Near-field coupling communication (NFCC) is a technology that uses the surface of the human body as a transmission path. To suppress the radiation signal from the human body, NFCC devices use a carrier frequency of less than 10 MHz. Because the radiation signal has the potential to disturb the other NFCC links, the radiation signal from other devices needs to be suppressed to ensure stable NFCC links. This paper describes our investigation of the interfering mechanism in NFCC systems to put the systems into practical use, such as at a ticket gate in the train station. We measured interference signal losses depending on the distance between two phantoms, regarded as human bodies. Based on the experimental and simulated results, an equivalent circuit of the signal interference was proposed. From the interference analytical model, we identified the capacitance that caused the interference problem and found that weakening the effects of this capacitance was important to achieve a stable NFCC link.

Analysis of signal propagation loss on the human body in intrabody communication

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 distributions on the body were evaluated with a high frequency structure simulator (HFSS). We found that the signal loss on the human body was affected by the shape of the body. These results enable us to design reliable NFCC links in various applications.

Propagation characteristics of MHz-band RF signals for intra-body communication

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 isolated probe. In addition, we evaluated the signal loss characteristics with a high frequency structure simulator. As a result, we found dependencies of signal loss on distance in both the experiments and the simulations.