| Popis: |
[ABSTRACT]The synthetic aperture radar (SAR) is a kind of active sensors. To acquire the images of target in remote area, the SAR uses microwave signal. Nowadays, Josaphat microwave remote sensing laboratory (JMRSL), Chiba university, Japan is developing the Boeing 737- 200 on-board X-band airborne SAR system. As the system requirements of proposed X- band SAR, the wide bandwidth of transmit signal, narrow beam width, beam tilting, and circular polarization are needed to support the high resolution image in range and azimuth directions. The frequency resouce is set to the center frequency on 9.4 GHz and the bandwidth of 800 MHz. Also, the antenna should support the tilt angle up to 35 degree. To realize these requirements, the array antenna which has same characteristic in each module is proposed in the paper. The proposed antenna has 6 modules and each module is designed as 2 by 6 elements. Considering the combination of these modules, the characteristic of each module is preferred to have same value because of used technic to tilt transmitted signal. The performance of proposed antenna has been verified based on the four performance eveluation parameters; return loss, axial ratio, gain, and radiation pattern. As a result, S11, gain and radiation pattern could acquire the almost same value. However, in axial ratio, there were some difference between each module. As a reason, the interference of transmitted signal is considered because of sequential array in object to be measured. |
