Toward space application
The technology outlined above has evolved for commercial applications, but can be applicable to space field. At present, very-large scale integrated circuit (VLSI) using Si digital signal processing is dominant in the commercial high-functional IC field. In recent years, even in the microwave band, microwave analog ICs using Si called RF-CMOS have become available. Although its performance is still far from that of the compound semiconductor MMIC, the author et al. are proposing a high-functional IC called the HySIC RF-Mixed Signal IC integrating the three components above. HySIC stands for 滴ybrid Semiconductor Integrated Circuit,・a system-on-chip fusing compound MMIC on a Si-base analog/digital hybrid IC.
At the module level, we have produced a prototype Active Integrated Antenna (AIA) consolidating the above high-function device, an MMIC amplifier and a small antenna. We are also trying to realize an electron-beam scanning-type Active Integrated Phased Array Antenna (AIPAA), which changes the antenna-beam direction by electrical control signal not mechanical operation. We believe that this is required technology to realize small, lightweight satellites by integrating onboard electronic instruments with HySIC. Moreover, this will enable in-satellite wireless communication eliminating the need for wire harnesses and reducing the payload.
For HPA using high-performance devices (non MMIC), we successfully designed and produced a prototype of solid-state high-power amplifier and, further, succeeded in improving its efficiency. This operates in both S band (2 to 4GHz frequency) and X band (8 to 12GHz). There are two types: 100W-class power type using GaN semiconductor device and 200W-class type using parallel combination of the devices. High-conversion efficiency is required for the amplifier in order to output efficiently DC electricity to activate the device as a microwave. We achieved 63% efficiency, a higher performance value than with conventional electron tubes. We then combined it with a solid-state cooler (Peltier device) to build a trial compact solid-state electron high-power amplifier (SSPA) and achieved 1kW output (shown in Fig. 3). It can be installed on base stations for broadcast or ground stations for space communication. A prototype 20kW-class SSPA is also under consideration for ground-space communication stations. These solid-state power amplifiers will probably be used in large antennas for radio-wave satellite tracking as a space-electronic technology and for communication with a variety of scientific satellites and earth observation satellites.
Combining these technologies, we recently conducted R&D on the use of radio-wave technology to solve environmental energy issues by green technology. In principle, it utilizes electrical power transmission via no-modulation radio waves (wireless electrical power). For the first time in the world, we succeeded in transmitting microwave power to a robot. We are also researching wireless-power transmission to sensors installed inside spacecraft with the aim of reducing spacecraft weight, increasing safety, etc. It is expected that these technologies will be applied to commercial and space fields immediately.
I was delighted to receive the prestigious Electronics Society Award from the Institute of Electronics, Information and Communication Engineers (IEICE) for our ICs using compound semiconductors and their system applications. The award was given on the theme of 電evelopment and quest for space applications of high-function compound ICs・in the 田ompound semiconductor and optical electronics・category and in close relation with this article.
My research over the past 20 years has been to fuse the manufacturing technology of microwaves and millimeter-waves with antennas as an element focusing on compound IC devices and high-frequency IC technology in the electronics technology field. I have advocated innovations at each step of design, fabrication and evaluation through trial production of actual devices. I would like to express my sincere gratitude to those who have supported me, including researchers at universities and companies, members of the electronics society, as well as ISAS and JAXA. I am determined to contribute to this field on the occasion of the electronics society award. I sincerely ask for your continuing support.