Masanobu Yajima

Development status of the beam steering control subsystem for the microwave power transmission ground experiment

The Japan Aerospace Exploration Agency and the Institute for Unmanned Space Experiment Free Flyer are planning to conduct a microwave power transmission (MPT) ground experiment in fiscal year 2014. We will use an important MPT technology called beam steering control (BSC). The BSC technology accurately controls microwave beam pointing to a power receiving subsystem. We researched the BSC method and the beam pointing accuracy. This paper describes the functions and specifications of BSC, and analysis results of beam pointing accuracy in the MPT ground experiment.

Development results of a proto flight model of the Ka-band active phased array antenna for WINDS

Wideband Inter Networking engineering test and Demonstration Satellite (WINDS) has been developed to realize high-data-rate satellite communication services for future multimedia applications. WINDS has Ka-band transmitting and receiving active phased array antennas (APAA) that can flexibly establish communication with any area by electronic beam scanning. We developed flight models of the APAA and verified its performance, including its radiation characteristics. This paper describes the design of the APAA and the development results of a flight model.

Preliminary experimental results of beam steering control subsystem for microwave power transmission ground experiment

The Japan Aerospace Exploration Agency (JAXA) has been studying Space Solar Power Systems (SSPS) since 1998. To achieve 1GW-class SSPS, a power transmitting subsystem on a square kilometer scale is required for microwave power transmission (MPT). Consequently, it is crucial to construct a number of transmitting modules in the power transmitting subsystem, and transmit microwave beams pointing accurately to the power receiving subsystem. To achieve MPT technology, JAXA and the Institute for Unmanned Space Experiment Free Flyer are planning to conduct a MPT ground experiment in fiscal year 2014. In this joint effort, we are in charge of a beam steering control (BSC) subsystem, which is important among MPT technologies. We have defined the functions and specifications of the BSC Breadboard Models (BBMs). This paper describes the functions and specification of the BSC BBMs, and the results of system tests.

Beam pointing error of wideband phased array antennas with reduced true-time-delay devices

Phased array antennas have primarily been used for narrowband systems such as radar. However, in recent years, these systems have been increasingly used for wideband applications, such as satellite communication. In this paper, we describe the beam shift principle of a wideband linear phased array antenna with reduced true-time-delay devices, as well as a simple formula for calculating the beam pointing error. The results obtained from the application of the formula were in concurrence with the simulation results. We also propose a simple method for compensating for the pointing error, and report the simulation results.

Active Phased Array Antenna for WINDS Satellite

[Abstract] Phased array antenna (PAA) has attracted attention for use as a hopping spot beam antenna that can potentially be used as an electronically controllable onboard satellite antenna. In fact, Japan Aerospace Exploration Agency (JAXA) has developed a Ka band active phased array antenna (APAA) installed on the Wideband Internetworking engineering test and Demonstration Satellite (WINDS). We developed flight models of the APAA and verified its performance, including its radiation characteristics. This paper describes the design of the APAA and development results of the flight model. I. Introduction PAA has attracted attention for use as a hopping spot beam antenna that can potentially be used as an electronically controllable onboard satellite antenna. In fact, a Ka band APAA will be installed on the WINDS. WINDS has been developed to construct a high-speed satellite communication system and demonstrate the advanced technology that is necessary for the formation of the satellite commnications network. The system aims at maximum speed of 155 Mbps / 6 Mbps for households with a 45-centimeter aperture antenna, which is the same size as existing communications satellite antenna, and ultra-high speed of 1.2 Gbps communication for offices with a five-meter diameter antenna. In addition to establishing a domestic ultra high speed Internet network, the project also aims to realize ultra-high speed international Internet access, especially with Asian Pacific countries and regions. WINDS project is under joint development by JAXA and National Institute of Information and Communications Technology (NICT). WINDS will be launched by an H-IIA Launch Vehicle in early 2008. The APAA is composed of a transmitting antenna and a receiving antenna, and each antenna has two hopping spot beams. The direction of each beam can be controlled independently, flexibly and rapidly. These beams can also realize the satellite switched time division multiple access (SS-TDMA) communication functions. The hopping spot beam function and SS-TDMA communication systems will be utilized for broadband communication experiments covering the Asia-Pacific region. The key features of the APAA are the minimal number of elements, development of RF components operating over 1.1 GHz bandwidth, monolithic microwave integrated circuit (MMIC) devices, and high density packages for miniaturization and lightness. This paper describes the WINDS APAA configuration, and development results of the flight model.

Development of Multi-Mode Integrated Transponder

During the last 20 years, TTC a satellite onboard demonstration model and a qualification test model. It will be a next-generation S-band standard for various kinds of JAXA LEO/GEO satellites and other operation or missions.

Beam Pointing Error of Wideband Planar Phased Array Antennas with Reduced True-Time-Delay Devices

Phased array antennas have primarily been used for narrowband systems such as radar. However, in recent years, these systems have been increasingly used for wideband applications, such as satellite communication. In this paper, we derive approximation formulas for calculating the beam pointing error of a wideband planar phased array antenna with reduced true-time-delay devices. The results obtained by the application of the formulas were consistent with the simulation results. We also propose a simple method for compensating the pointing error and demonstrate that the method is effective using simulation results.