In this work a plane wave is used to localize a point target and in addition to speeding up the imaging scenario rather than moving the antenna to synthesize the long aperture as done in conventional SAR instead of moving the antenna to synthetize the long aperture a single plane wave transmitter and a linear passive antenna array for the receiver are used. Single plane wave transmitter in far field is considered as an abundance of narrow beam width along a line parallel to the target. Transmitter antenna illuminates the target in all positions directions that the radar used to move in SAR technique. The Linear array is put in a closer distance to the target and collects the back scattered field coherently in a several positions. This collection will be considered as a strip map SAR mode. The proposed technique is implicitly the same as SAR technique. The SAR standard imaging image processing, back projection algorithm is used to construct the image. Since the proposed technique transmits a plane wave for a single time and the linear array collects data in all positions simultaneously, the speed of this technique is considerably more than the conventional SAR تفاصيل المقالة

Ground penetrating radar (GPR) is one of the most important instruments in some cases such as remote sensing, non-destructive evaluation and microwave imaging. The radiation component (antenna) in these radars is very important. Features and constraints such as high impedance bandwidth, stable radiation patterns, minimum distortion of the antenna end reflections and consequently sending high-precision pulses makes many challenges in construction and design of the antenna. In addition, the antenna size, which is expected to cover both low frequencies and portability, adds to the difficulty of designing this antenna. In this paper, four possible modes of wire bowtie antenna, which is known as one of the most common antenna in impulse GPR applications are introduced and investigated. To this regard, late-time-ringing effect of the transmitted UWB waveform, pattern characteristics and impedance bandwidth of the proposed structures have been analyzed and compared. The results show that the other modes can be replaced to the original one in most cases. تفاصيل المقالة