Side lobe control of UWB antenna array for real beam radar imaging

The ultra wideband (UWB) array waveform is essential to the improving of resolution for microwave imaging. Large antenna arrays provide high angular resolution microwave images. These images are plagued with artifacts caused by high side lobes. Specifically, these artifacts are false targets and target break-up or speckle. In this paper, an UWB comb taper slot antenna array with large element spacing and impulse excitation is studied. The four-element UWB array system with uniform and non-uniform element spacings in the broadside direction is analyzed by energy pattern for side lobe control. A technique for beam scanning with a time delay technique is developed for UWB arrays. Different excitation pulse width is studied for peak side lobe that is far away from the designed beam direction of UWB array with uniform element spacings of 8.5 and 18 cm. Energy patterns for simulation and measurement are in good agreement. The periodic grating lobes of the UWB antenna array do not occur in the energy pattern, even if the element spacing and scan angle are large. In general, the optimum design of array element spacing is required for special applications.