An S Band Ultra-Wideband Dipole Antenna Array for Through-Wall Radar Application

For the application of through-wall imaging, an S band ultra-wideband dipole antenna is proposed in this manuscript. The antenna consists of two end-folded dipole antennas connected in parallel, and a section of T-shaped microstrip line is used for coupled feeding to achieve miniaturization and wideband. Test results show that the prototype has 56% passband, and 2.5GHz is the center frequency, with size of
$0.46\lambda\times 0.38\lambda (\lambda$
is wavelength with the center frequency). By placing a reflector 40mm behind the substrate without affecting bandwidth, 8dBi gain can be achieved. In addition, a dipole array is formed by using this element to increase the gain to 10 dBi. The compact structure makes it very suitable for radar systems operating in S-band.