Ultra-wideband tapered-slot antenna with non-uniform resistive loading

Several designs of tapered-slot antennas for ultra-wideband applications such as ground penetrating radar are described. The antennas for subsurface imaging must be damped to decrease clutter arising from the ringing of the antenna. The ringing is caused by the internal or open-end reflections as well as multiple reflections between the antenna and ground surface. In the proposed design, the ringing has been partially suppressed by corrugations and/or resistive films applied on the antenna flares in different ways. Performance of the antennas has been estimated using the electromagnetic simulation software. It was found that resistive loading of the antenna flares results in decrease of the return loss and increase of the directivity at low frequencies that diminishes the clutter. This is demonstrated also in the simulations by the impulse waveform received by a small probe placed in the antenna near field.