Akira Akaishi

A 50% PAE K-Band Power MMIC Amplifier

This paper describes the successful development of a 2-stage power amplifier (PA) with 50% efficiency at K-band. A 3-stage variable gain amplifier (VGA) was also developed for a driving stage. Metal - Insulator - Metal (MIM) capacitors and high impedance lines are employed as matching elements to accomplish a compact chip size. As a result, these amplifiers achieve compact chip sizes of 1.0 × 2.0 mm2. In designing the PA, gate widths in the first and second stages are optimized to achieve high efficiency. The PA and VGA have linear gains of more than 18 dB and 24 dB from 18 GHz to 20 GHz, respectively. The PA delivers an output power of 24.6 dBm and a power added efficiency (PAE) of as high as 50% at 19 GHz. To our knowledge, this is the highest PAE at K-band. These results are promising for onboard light weight Active Phased Array Antenna (APAA) at K-band.

GLOBAL RING SATELLITE COMMUNICATIONS AS A 2G-SATELLITE CONFIGURATION

The purpose of this paper is to propose a possible configuration of a global ring satellite communications system as a 2G-satellite (second generation Internet satellite) for the future high capacity satellite. First, it reviews the future communication satellite R&D needs. The future vision of the communication satellite R&D is that the first generation Internet satellite (1G-satellite) having a capacity of 5-50 Gbps per satellite for 2000-2010, the 2G-satellite having a capacity of 50-500 Gbps per satellite for 2010-2020 and the 3G-satellite having a capacity of 0.5-5 Tbps per satellite for 2020-2030. Second, the paper proposes a configuration of the 2G-satellite with global ring capability. The proposed system is consisted of geostationary satellites linked up with the optical inter-satellite link (ISL) for the global ring coverage. In this paper, a configuration of a 1.5-2G-satellite is given, which has a global ring capability and has capacity of 60-120 Gbps. The paper gives how to design the optical ISL in detail. The concrete configuration of the 2G-satellite considered. Finally, the paper discusses a further study items briefly.

Development results of partial model of a Ka-band active phased array antenna for gigabit satellite

The high data rate and global satellite communication systems are expected to be an improvement agenda to the social and economic activities in the 21st century. The experimental high data rate (gigabit) communications satellite is required to face the technological challenges of the future growing multi-media applications. For this gigabit communications system, a Ka-band scanning spot beam antenna (SSBA) which realizes multiple beam forming is required. CRL and MELCO have been developing Ka-band active phased array antenna (APAA) for the SSBA as one of the most important and challenging technology. An APAA has been developed mainly for radar systems for many years. CRL and MELCO are investigating and developing the direct radiating APAA for communication satellites which can operate under wide frequency band in Ka-band. This paper describes the preliminary study results of the Ka-band APAA for gigabit satellite and the radiation performances of the partial experimental model of Ka-band APAA with two multiple beams to both transmit and receive signals. The partial model includes the active MMIC device such as HPA (high power amplifier), LNA (low noise amplifier) and PS (phase shifter), and multi-layered BFN (beam forming network) as key components. Performances such as radiation pattern, beam scanning performance and input-output performance have been measured. We also verified that the REV (rotating element electric-field vector) method was effective for pattern calibration.

Concept of Satellite Communication Facility for Disaster Support located in the Tohoku District

It is increasingly difficult to rely solely on terrestrial communications for use during disasters when the terrestrial communication infrastructure is extensively damaged in the affected area. After the Great East Japan Earthquake, fully automatic transportable earth stations were recognized as being among the most important aspects of disaster response. The National Institute of Information and Communications Technology (NICT) commenced the development of fully automatic earth stations and a test facility in the Tohoku district. A satellite communication network can be easily deployed using these automatic earth stations to cover the affected areas, and the communication links can be steadily re-established. We also recognized that the drastic increase in traffic during such disasters significantly affected the limited communication