The Impact of Bandwidth on Through-the-wall Radar Imaging

An electromagnetic model is simulated using finite difference time domain for through-the-wall radar imaging. In the numerical simulation narrow-, wide-, and ultra-wide-band signals are used as emission sources. The back projection algorithm is applied to image square and rectangular ideal metal bodies based on a refraction model. The results demonstrate that there is obvious refraction in the through-the-wall propagation of electromagnetic waves. For the calculation of propagation delay, the variation in propagation path and time must be taken into account. Then the actual refractive point is found accurately and rapidly according to Fermat's principle. For imaging, all three signal sources can be used to acquire the image. The image result is best for the ultra-wide band and worst for the narrow-wide band. For the azimuth, synthetic aperture technique is adopted to achieve high resolution. For the range, there is a positive proportional relationship between the resolution and signal bandwidth. The wide band signal significantly increases the range resolution. Therefore, ultra-wide band SAR radar has more precise imaging and positioning capabilities. Copyright © 2014 IFSA Publishing, S. L.