Mitsuru Shinagawa

A near-field-sensing transceiver for intra-body communication based on the electro-optic effect

This paper describes a near-field-sensing transceiver for intrabody communication, in which the human body is the transmission medium. The key component of the transceiver is an electric-field sensor implemented with an electrooptic crystal and laser light. This sensor is suitable for detection of the small and unstable electric fields produced by the human body because it has extremely high input impedance. This transceiver enables IEEE 802.3 half-duplex communication of 10 Mb/s through a persons body in an operating range of about 150 cm between the hands. The packet error rate of 0.04% is obtained at packet size of 1070 octet. This paper explains the configuration and performance of the transceiver and presents results of a communication test.

Principles and Demonstration of Intrabody Communication With a Sensitive Electrooptic Sensor

We have investigated the basic principles of intrabody communication with a newly developed ridge-type electrooptic (EO) sensor. To intuitively understand the essence of intrabody communication, we introduced a simple model based on the fact that human body can approximately be considered as a conductor wrapped in an insulator. To demonstrate the propriety of the model, we measured the characteristics of communication systems including a human body using the EO sensor. The experimental results well agree with the predictions from the model. The new ridge-type EO sensor is shown to be superior to our previous EO sensor, both in sensitivity and in stability. With the ridge-type EO sensor, we succeeded in 10-Mb/s data transmission through the human body. Furthermore, we discussed the advantages of using the EO sensor for intrabody communication.

1.55-/spl mu/m photonic systems for microwave and millimeter-wave measurement

This paper reviews recent advances in 1.55-/spl mu/m photonic systems for measurement and sensors covering the frequency range from microwaves to millimeter waves. We first deal with the basic technologies for photonic measurement, i.e., generation, transmission, and detection of high-frequency signals, and then discuss recent practical applications, including high-speed integrated-circuit probers, sampling oscilloscopes, network analyzers, and some free-space sensing systems.

An automated electro-optic probing system for ultra-high-speed IC's

This paper describes an automated optical probing system based on external electro-optic sampling for the internal diagnoses of ultra-high-speed ICs. A workstation-controlled environment, automatic probe positioner, and module-based system architecture make the system easy to use, and improve measurement accuracy and reproducibility. Voltage sensitivity is routinely obtained on an order of 1 mV//spl radic/(Hz) at frequencies up to 70 GHz. The system has been successfully applied to the internal-node measurement of on-wafer digital ICs operating at 20 Gb/s. >

CarpetLAN: a novel indoor wireless(-like) networking and positioning system

CarpetLAN is a novel indoor wireless(-like) broad-band networking and positioning system. It uses the floor surface and the human body as an Ethernet-cable, and weak electric fields as the transmission media. Portable and wearable devices can connect to the network while the user stands or walks on the floor; connection speed is 10Mbps. Home and office appliances can also access the network if they are just put on the floor. CarpetLAN also provides an indoor positioning function, which is urgently needed for realizing “ubiquitous” communication. This electric field based transmission system yields ultra-micro communication cells, so the positions of humans and appliances can be detected with about 1 meter accuracy.

A laser-diode-based picosecond electrooptic prober for high-speed LSIs

An external electrooptic (EO) prober to diagnose high-speed LSIs is described. The prober employs a GaAs probe tip as a proximity electric field sensor and a semiconductor laser diode as an optical sampling pulse source. Polarization detection optics of the prober are compactly implemented in a specially designed electrooptic sampling (EOS) module. Accurate and reproducible measurement is achieved with the module and a precise EO probe positioner. The minimum detectable voltage is 16 mV/ square root Hz, which is sufficient to measure an emitter-coupled logic (ECL) level signal of less than 1 V. The temporal resolution is 24 ps, which is now limited by the optical sampling pulsewidth. The system is successfully applied to measure waveforms of internal nodes of gigahertz-band LSIs. >

Human-area networking technology based on near-field coupling transceiver

We discuss a novel communication technology that uses the human body as a communication path. The conventional body-channel communication systems are composed of only transceivers (TRX) on the human body. Our proposed system is composed of not only transceivers on the body (wearable TRX) but also transceivers embedded in floors, PCs, equipments, etc (embedded TRX). Therefore, our system broadens the fields of application. To estimate the transmission quality of our system, we measured the packet error rates (PER) between a wearable TRX and an embedded TRX. The PER during downlink was better than that during uplink. We describe a method for improving the PER during uplink with a common mode filter and show the PER characteristics.

A novel high-impedence probe for multi-gigahertz signal measurement

This paper describes a novel high-impedance hand-held probe based on electro-optic sampling (EOS) for multi-GHz signal measurement of on-board circuits. The probe head and detection optics are assembled into a compact probe module. The probe head consists of a metal needle tip and an EO material. The top of the needle is bonded to the EO material. When the needle makes contact with the signal line of a circuit under test, the signals are measured by detecting the polarization change of laser pulses that propagate through the EO material. The effective 3-dB down bandwidth of the EOS high-impedance probe is 10 GHz. The voltage sensitivity is 0.5 mV//spl radic/Hz. The input resistance and capacitance are >100 M/spl Omega/ and <0.2 pF, respectively. The probe head is very durable and is not susceptible to electrostatic discharge. The probe has been successfully applied to measure multi-GHz signals of on-board communication ICs.

Signal-to-Noise Ratio Analysis of a Noisy-Channel Model for a Capacitively Coupled Personal Area Network

We investigated a noisy-channel model for a capacitively coupled personal area network (CC-PAN) with megahertz-frequency signals. The new channel model describes the influence of a power line connected to transceivers. Using the model, we analyzed characteristics of a CC-PAN channel in detail. The signal-to-noise ratio (SNR) for the CC-PAN channel can be calculated from the model. It is also shown that the SNR can be enhanced by using a common-mode choke. We also give a physical interpretation of the mechanism of the SNR enhancement. Furthermore, we propose design guidelines to obtain a large-SNR CC-PAN system. The validity of our model and analyses are confirmed by experimental results.

Picosecond-switching time of In/sub 0.53/Ga/sub 0.47/As/AlAs resonant-tunneling diodes measured by electro-optic sampling technique

To demonstrate picosecond-switching time for In/sub 0.53/Ga/sub 0.47/As/AlAs resonant-tunneling diodes (RTDs), we fabricated RTDs with various barrier widths and measured their switching times using electro-optic sampling technique specially arranged for RTDs with high current density. For an RTD having the barrier width of 1.4 nm with the peak current density of 4.5/spl times/10/sup 5/ A/cm/sup 2/ and peak-to-valley ratio of 3.9, the switching time of 2.2 ps has been observed.