JRC REVIEW No.64 Technical Reports

- Special Issues : Research and Development-

JRC has been developing compact, low-cost, and high efficiency Digital Pre-Distortion (DPD)power amplifiers for mobile base stations. In this paper, we report two techniques developed for realizing higher efficiency of the power amplifiers. Firstly, we introduce JRC's proprietary fast DPD algorithm, reducing the computational load required. It was demonstrated through computer simulations that this developed DPD achieves an adjacent channel leakage power ratio (ACLR) of -50dBc within 1ms. Secondly, we introduce transmission leakage cancellation technique, which utilizes digital signal processing, to lower duplexer's isolation requirement in exchange for reducing its insertion loss, consequently improving equipment's power efficiency. We show that the increased transmission leakage resulting from the relaxed isolation requirement can be canceled by up to 30dB for a prototype.

Koji Fukino
Yasumasa Koiso
Yoshifumi Shinfuku
Eiki Takahashi
Masatoshi Nagayasu

- Special Issues : Research and Development-

Microwave filter is an essential component for radio and wireless system. JRC has been developing various types of microwave filters located between front-end module and antenna. In this paper, we describe the microwave filters focused on the equipment of Radar system and Multiplex radio communication system. These system requires quite low loss characteristics for filters realized utilizing waveguide component.

Kazuaki Yoshida

- Special Issues : Research and Development-

The antennas used in the mobile earth station have been developed, such as the planar antenna for INMARSAT Fleet Broadband series JUE-500/JUE-250 and the helical antennas for INMARSAT C JUE-85, respectively. Recently, requests for the network environment with high functionality and high reliability are increasing from many customers. In order to respond the above mentioned requests, JRC has developed the antennas as the successor model JUE-501, JUE-251 and JUE-87, which are employing the thin PCBs such as FPC and forming materials. As a result, the antennas with light weight and high reliability are realized.

Yusuke Kato
Takanori Noro

- Special Issues : Research and Development-

X-band radars are widely used for shipborne navigational aids and vessel traffic management systems. As for the radars operated on such high frequency, targets are likely to be obscured by the clutter signals scattered from sea surface, rain and snow. The scan-to-scan integration-correlation processing is one of the most effective techniques to enhance the target signals obscured by the clutter signals; however, the processing inevitably suppresses moving targets as well as the clutters. JRC has extended the conventional scan-to-scan integration-correlation processing to accommodate moving targets and also to achieve higher suppression against clutters. The new method evaluated on a real data has demonstrated the signal-tonoise ratio-improvement 8dB higher than the conventional method, for a fast-moving target under strong clutter environment.

Takuya Takayama
Yukinobu Tokieda
Hiroki Sugawara

- Special Issues : Research and Development-

The antenna for general shipborne 9-GHz band radars requires roughly 100 elements for the composition in the form of a phased-array antenna; thereby the cost problem arises. As a solution to the problem, JRC has adopted the virtual array technique to reduce the number of necessary elements down to 16 for the transmitting antenna and the receiving antenna, respectively; nevertheless supporting the radar performance equivalent to systems with a 100-element antenna. We have evaluated the effect of the virtual array technique, throughout computer simulations and field experiments of the prototype radar with a virtual array antenna. Our evaluation shows that our novel technique is capable of sufficient performance for shipborne radars despite its reduced composition.

Masayuki Sugano
Takuya Takayama
Yukinobu Tokieda
Hiroki Sugawara

- Special Issues : Research and Development-

Weather radar acquires conditions of weather, such as amount of rainfall and snowfall in the air. The observed data from weather radar are widely applicable for weather forecasts, weather alert and various other fields. Waveguide rotary joints allow the directional antenna to rotate while passing microwave signals to and from the transceiver. The rotary joints installed on the weather radar are required steady characteristics and long life operation. Since JRC has developed the waveguide rotary joints with high reliability that incorporated both mechanical components selection and optimized transmission characteristics specialized for weather radar, we introduce about this device in this paper.

Shoji Ishizaki
Yukiharu Harikae
Keiichi Natsuhara
Toshihiro Haneda
Hideyuki Takeuchi
Shioda Toshio

- Special Issues : Research and Development-

Recently, with the rapid spread of portable wireless communication terminals represented by smartphones, there is an increasing demand for large-capacity wireless infrastructure equipment. Quasi-millimeter-waves/ millimeter-waves are suited for this purpose because of their broadband and high speed properties. JRC has developed multi-function millimeter-wave monolithic microwave integrated circuits (MMICs) in order to smaller volume and lighter weight of these broadband wireless communication equipments. Compared with the conventional MMIC using microstrip lines, the chip areas of the MMIC using coplanar lines and the MMIC with a 3-dimensional structure are reduced to 2/3 and 1/3, respectively. The developed MMICs, housed in small and low loss packages assembled by JRC proprietary face-down chip technology, have sufficient reliability for outdoor applications. The quasi-millimeter-band MMIC is used in a 25GHz broadband wireless point-to-point communication system and the millimeter-band MMIC is used in a 38GHz ultra broad band wireless communication system. These systems are seamlessly connected to the fiber optic network.

Nobuyuki Adachi
Toru Taniguchi
Toshifumi Shirosaki
Shinji Nagamine
Jun Kobayashi

- Special Issues : Research and Development-

POCT (Point of Care Testing) which is a diagnostic testing at or near the patients has been required for the near future medical and healthcare systems. In this paper, an immunoassay-based biosensor using shear-horizontal surface acoustic wave (SAW) devices for POCT applications is described. A temperature-stable 250 MHz delay-line type SAW biosensor was fabricated on quartz substrates. SAW velocity changes due to antigen-antibody reactions were observed as we expected and quantitative results were obtained. In addition, a working prototype of SAW biosensors which connects to a smart-phone was demonstrated for future home healthcare applications.

Hiromi Yatsuda
Takashi Kogai
Mikihiro Goto
Osamu Iijima
Suguru Kasai

- Special Issues : Research and Development-

JRC has been developing SAW sensor devices as a SAW application to non-communication field during the past few years. SAW liquid sensor, a sort of the developments, is an electronic device that can detect wide variety of physical quantity of liquids by use of surface acoustic wave properties. SAW liquid sensor is one of the most promising devices in the wide range of sensing applications by reason of its excellent productivity. As an application of SAW liquid sensor, JRC has developed a SAW methanol concentration sensor for DMFC, which is an attractive device as mobile power sources. Although the developed sensor has simplified structures, the sensor shows equal measurement performances with its competitive devices. Also, excellent responses of the developed sensor to characteristics change of specimen liquids, which was unknown before that, have been discovered during the evaluations. This report describes general descriptions of SAW methanol concentration sensor and evaluation results.

Koji Kano
Takashi Kogai
Naoyuki Yoshimura
Osamu Iijima
Toshimasa Mori
Hiromi Yatsuda