| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1997: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1996: ¥1,200,000 (Direct Cost: ¥1,200,000)
|
|---|
| Research Abstract |
As a method of compensation of rain attenuation, we construct aperture synthesized antenna, which is applied a principle of an interferometer to, consisted of two small aperture parabolic antennas. We have observed Broadcast Satellite wave with that aperture synthesized antenna and other single parabolic antennas, and compared attenuation characteristics.
First we made a common local oscillator with a Gunn diode which generates a 10 GHz signal. That shows 21 dBm output power and (]SY.+-。[)2 MHz/day frequency variation. We reconstructed two down converters to be commonly fed a local oscillator signal from the exterior.
Aperture synthesized antenna is composed of two offset parabolic antennas, whose short diameter is 50 cm, and has 8 m baseline length because we use aperture synthesized antenna together another observation. Other single antennas which we use for comparison are two offset parabolic antennas, 50 cm short diameter and 75 cm, and one center feed parabolic antenna, 30 cm diameter.
In comparison of 50 cm single antenna, the sythesis antenna improves rain attenuation by 1.1 dB.Improving matching section of power combiner, it will be made better.
Also among three single antennas, we compare rain attenuation characteristics when rain intensity is over 10 mm/h. We find the 50 cm antenna is most influenced by rain, and in order 75 cm, 30 cm. We think that is caused by antenna beam pattern and rain area size. So we propose to continue an observation in detail. And if we can, using sythesized antenna which is composed of more small aperture antennas, for example 30 cm diameter parabolic antennas, it is necessary to observe rain attenuation.
|
