58 research outputs found
Measurements and Characterization of Ultra Wideband Propagation within Spacecrafts--Proposal of Wireless Transmission for Replacing Wired Interface Buses
Development of high-speed and high-efficiency downlink transmitter with GaN-HEMT amplifier and pre-distortion technique for nano/small satellite
A high-speed downlink telecommunication system is required to meet various applications for small satellites such as earth observation. The purpose of this research is to develop a high-data-rate (typically over 300Mbps) communication system. Generally, the operation at nonlinear region provides high efficiency for a RF power amplifier. However the amplitude-phase modulated signal, which is an efficient scheme in term of frequency band, requires high linearity. In order to amplify amplitude-phase modulated signal for high data rate, a 2W X Band GaN-HEMT power amplifier and digital pre-distortion technique were developed. In this paper measurements and simulations of the system are presented
Automatic Determination of Phase Centers and Its Application to Precise Measurement of Spacecraft Antennas in a Small Anechoic Chamber
Analysis of Photoinduced Change in Properties on Macroscopic Motion of Crosslinked Azobenzene Liquid-Crystalline Polymers
Distinct Photochemical Phase Transition Behavior of Azobenzene Liquid Crystals Evaluated by Reflection-Mode Analysis
Synthesis of Novel Liquid-Crystalline Thiophene Derivatives and Evaluation of Their Photoresponsive Behavior
PHOTOINDUCED BENDING UPON PULSED IRRADIATION IN AZOBENZENE-CONTAINING CROSSLINKED LIQUID-CRYSTALLINE POLYMERS
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