抄録
Offer Organization: Japan Society for the Promotion of Science, System Name: Grants-in-Aid for Scientific Research, Category: Grant-in-Aid for Scientific Research (A)., Fund Type: -, Overall Grant Amount: - (direct: 23100000, indirect: -)
Millimeter(MM) wave focal plane imaging is able to provide information through clouds, smoke, and dust when visible and IR systems are unusable. It can also be used in the fields of plasma measurement remote sensing, etc. Conventional millimeter wave imaging relies mainly on the use of a single detector, with the optics mechanically scanned to obtain an image. The use of multiple detectors in an imaging array, however does not require mechanical scanning and makes real-time imaging possible. The object of this research is to develop an element for the imaging array. The element consists of a wide-band antenna, LNA (Low Noise Amplifier), a detector and a low-pass filter. The development of MM-wave optics to form images is also important. The results of this research are as follows :
1. Considering atmospheric attenuation as a function of frequency of MM-waves, theoretical analyses for passive imaging array elements have been performed to give required characteristics of the elements and the frequency for the experiments to be 35 GHz.
2. The ray-tracing method was used to design MM-wave optics with less aberration. An aspherical lens with a diameter of 500 mm was made using polyethylene.
3. A wide-band tapered slot antenna with the taper curve of Fermi-Dirac function was developed for the elements (patents pending).
4. LNA's for the 35 GHz band have been designed and constructed using commercially available MMIC's to have an amplifier of 40 dB gain and 7 dB NF.
5. Using the imaging element, outdoor scenes such as sky, building and trees and also human body such as face and hand have been successfully observed at the 35 GHz band. The applications of the MM-wave passive imaging include robot sensors through flame, detection of land mines and so on.