一种220 GHz波段太赫兹合成孔径成像雷达

Terahertz Synthetic Aperture Imaging Radar Based on 220 GHz Band

微波频段的机载合成孔径成像雷达在对地观测方面具有广泛应用,但其合成孔径成像积累时间长,成像帧率低,提高雷达工作频率能够减小合成孔径所需转角,提高成像帧率。设计了一种工作在220 GHz波段的太赫兹合成孔径成像雷达系统,采用收发天线分置、发射宽带线性调频连续波的体制,最大信号带宽4.8 GHz,输出信号功率约20 m W。宽带回波信号幅度相位经外标校补偿,通过成像试验,验证了太赫兹ISAR与SAR成像分辨率约3.2 cm,可实现5Hz的成像帧率,证明太赫兹波段能够大幅提升成像帧率,满足快速成像的要求。

Airborne synthetic aperture imaging radar in microwave band is widely used in earth observation,however,its synthetic aperture imaging has long accumulation time and low imaging frame rate. Increasing operating frequency of the radar can reduce the required angle of the synthetic aperture and increase the imaging frame rate. A terahertz synthetic aperture imaging radar based on 220 GHz band is presented. The receiving and transmitting antennas are separated. The system uses a linear frequency-modulated continuous-wave（ LFMCW） waveform. The output terahertz signal power is about 20 m W and a 4.8 GHz instantaneous bandwidth signal is achieved. The experiments verify that the resolution of terahertz ISAR and SAR imaging is about 3.2 cm,and the imaging frame rate of 5 Hz can be achieved. It is proved that terahertz band can greatly increase the imaging frame rate and meet the requirements of fast imaging.