Koji Tanaka

In this paper, prototypes of a retorodirective active integrated antenna are reported for microwave power transmission in the Space Solar Power Satellite (SSPS) system. As one of the important function required spacetenna, the retrodirectivity was examined. Using a heterodyne mixing method, the authors proposed the concept of retrodivective active integrated antenna with the parallel feed back oscillator and the patch antenna. Using the two types of power divider, the retrodivective active integrated antenna for the response signal was made and its fundamental principle was confirmed. Further, by making the prototype of the retorodirective array for the question and response signals, the circuit configuration and measurement results of the simple retrodirective active integrated antenna are described.

We propose space experiments in order to verify significant technologies and to promote public awareness of the Solar Power Satellite(SPS). Some technical and engineering problems were still remained toward SPS. The main missions we proposed is wireless power transmission(WPT)experiment from Low Earth Orbit(LEO)to the ground using one satellite that can be launched by only one large launch vehicle such as the HII-A. The WPT technologies for SPS, which are the direct detection of rectenna sites, and the microwave beam control skill with high angular precision, will be verified and established. The large phased array antenna system that radiates the microwave with a power of around 400 kW was considered.

In conceptual study of SPS2000, which was conducted by ISAS Solar Power Satellite (SPS) working group in Japan, technical and engineering problems were identified. Especially, microwave power transmission (WPT) and high power operation of solar arrays are key features that are required space experiments for SPS. In order to verify these technologies and to promote public awareness of the SPS, we propose a demonstration of WPT experiment from Low Earth Orbit (LEO) to the ground and a high power operation in the space environment using one satellite that can be launched by only one large launch vehicle such as the H-IIA or Ariane V. Solar arrays, which are consisted of thin flexible solar cells, on the satellite generate more than several ten kW. The life span and the influence of space debris in LEO concerning the solar arrays are tested. The microwave generator and transmitter are installed on the satellite. The frequency of the microwave is 5.8 GHz in order to make the transmitter small. The microwave power of more than 100 kW is radiated from the phased array antenna system. Propagation characteristics of the microwave in the ionosphere and the atmosphere are examined by receiving the transmitted microwave.

We propose space experiments in order to verify significant technologies and to promote public awareness of the Solar Power Satellite(SPS). Some technical and engineering problems were still remained toward SPS. The main missions we proposed is wireless power transmission(WPT) experiment from Low Earth Orbit(LEO) to the ground using one satellite that can be launched by only one large launch vehicle such as the HII-A. The WPT technologies for SPS, which are the direct detection of rectenna sites, and the microwave beam control skill with high angular precision, will be verified and established. The large phased array antenna system that radiates the microwave with a power of around 400 kW was considered.

We numerically analyze a linear dispersion relation for quasi-TE modes propagating in a sinusoidally corrugated metal wall slow wave structure. Numerical result for quasi-TE_<11> mode is compared with that for the conventional TM_<01> mode. Experiments on a high power backward wave oscillator with an intense electron beam are carried out based on the numerical results near 2π-mode condition. The microwave output power, frequency and efficiency are measrued. The TE_<11> mode in addition to TM_<01> mode microwave radiation is observed far from π-mode region of operation. It is confirmed that oscillation property of quasi-TE_<11> and TM_<01> modes agrees fairly well with numerically predicted values. The study of quasi-TE mode oscillation is required for an optimum design of high power backward wave oscillators which work in a single frequency ofer a wide range of operating conditions.