Tetsuo Horimatsu

Path-Loss Prediction Models for Intervehicle Communication at 60 GHz

Propagation path losses affecting intervehicle communication (IVC) at 60 GHz are presented. In order to examine the radio-propagation characteristics in the IVC system, in the first stage of our investigation, we have carried out propagation tests between two vehicles communicating in a line-of-sight (LOS) situation at fixed positions on a smooth surface paved with asphalt, which is the normal communication condition. Furthermore, the non-LOS (NLOS) situation with up to three intermediate vehicles, which can cause an obstruction, has been conducted. To construct path-loss models in NLOS cases, the uniform theory of diffraction technique was applied to the calculation of waves propagating through the intermediate vehicles. The propagation path models were derived from the measured results. In the second stage, a path-loss prediction formula was derived by statistically processing the data that had been calculated using the propagation path model. The propagation tests between the vehicles in motion confirm that the path-loss prediction formula is very useful when the communicating vehicles are moving, and it is therefore suitable for designing the cells that form the IVC.

OEIC technology and its application to subscriber loops

Recent progress in GaAs- and InP-based optoelectronic integrated circuits (OEICs) for use in optical fiber transmission systems is reviewed. OEIC technology and system demonstrations for short-haul and high-speed transmission are described, and the problems arising in practical applications are discussed. Approaches to resolution of these problems are presented, and future OEIC applications, especially with regard to subscriber loops, are predicted. >

Crosstalk characteristics of Ti-LiNbO 3 intersecting waveguides and their application as TE/TM mode splitters

Crosstalk characteristics of an intersecting waveguide are presented. Two straight channel waveguides which intersect at an angle of a few degrees on y -cut LiNbO 3 were fabricated by in-diffusion of Ti. Experimental results show that the crosstalk characteristics are determined by the refractive index change profile and the geometry of intersection associated with guided wave modes. In a special case, a TE/TM mode splitter was obtained by using the intersecting waveguide which provides adequate anisotropy by the change in refractive indices. Splitting ratio was 17 and 14 dB for the TE and TM modes, respectively.

4*4 OEIC switch module using GaAs substrate

A compact 4*4 optical switch module consisting of a monolithic 4-channel OEIC receiver chip, a 4*4 GaAs IC chip, and a 4-channel OEIC transmitter chip has been developed for the first time. The module offers good performance, without an optical loss, a bandwidth of more than 600 MHz, and a crosstalk between neighboring channels of less than -20 dB. It has a good switching and distributive performance for high speed optical input signals of 560 Mbit/s. The switch module is attractive for use in high data-rate optical communication systems, particularly in local area networks, CATV systems, and intra-office links. >

Compact transmitter and receiver modules with optoelectronic-integrated circuits for optical LAN's

Compact transmitter and receiver modules with monolithic optoelectronic-integrated circuits, i.e., OEICs, are demonstrated, and 400- and 800-Mbit/s transmission experiments are successfully carried out over up to 4 and 2 km, respectively, with these modules, for the first time. The design of the monolithic-integrated circuits and the compact module structure are presented. The soldering technique based on the use of YAG laser simplifies the packaging procedures, and an efficient and simple scheme for coupling between OEICs and fibers make the OEIC modules compact. Both modules are attractive for applications in high data-rate communication systems, particularly in local area networks, CATV systems, and intra-office links.

Crosstalk Characteristics of Ti-LiNbO/sub 3/ Intersecting Waveguides and Their Application as TE/TM Mode Splitters

Crosstalk characteristics of an intersecting waveguide are presented. Two straight channel waveguides which intersect at an angle of a few degrees on y-cut LiNbO/sub 3/ were fabricated by in-diffusion of Ti. Experimental results show that the crosstalk characteristics are determined by the refractive index change profile and the geometry of intersection associated with guided wave modes. In a special case, a TE/TM mode splitter was obtained by using the intersecting waveguide which provides adequate anisotropy by the change in refractive indices. Splitting ratio was 17 and 14 dB for the TE and TM modes, respectively.

Radio communication technologies for vehicle information systems

Publisher Summary This chapter introduces the intelligent transportation systems (ITS) from a standpoint of radio communication technologies for information and communications for transportation systems. An integration method of wireless multiple services in ITS that is based on common frequency band radio on fiber (CFB-ROF) technique is proposed. The CFB-ROF will become a key technique for mobile multimedia communications in ITS. An inter-vehicle communication system (IVC) system was prepared to investigate the behavior of propagation characteristics comprehensively. Various services of the ITS-driving information, drivers assistant information, and vehicle control data can be provided for vehicles by using both the road-vehicle communication (RVC) and the IVC systems. Moreover, automotive radar systems have already been practically used for collision avoidance. The chapter also introduces the present research and development of the optical and millimeter-wave devices, which make it possible to downsize the RVC system and the automotive radar system.

A 6-GHz Four-Stage GaAs MESFET Power Amplifier (Short Papers)

A 6-GHz GaAs MESFET power amplifier with 1-W output power, 26dB gain, and 8-dB noise figure is described. It is a fully integrated four-stage amplifier with an efficiency of 22 percent. The third-order intermodulation product is 31.5 dB below the carrier at an output power of 1 W.

Low-voltage gigabit optical transmitter using a direct logic gate modulation of a tandem-electrode laser

We propose a new direct-modulation scheme for use in a high-speed optical transmitter with a direct logic gate connection to a laser diode. We have confirmed gigabit-per-second operation with voltage modulation onto a tandem-electrode laser.