Analysis on the time-domain transfer characteristics of UWB TEM horn antenna

In this paper, the time-domain field-to-circuit transfer characteristics of UWB TEM horn antenna were studied with analytical method and simulation method respectively. To obtain the electric field waveform in the far-filed region of the TEM horn excited by any voltage sources, we could first get the coupled voltage waveform of the antenna illuminated by impulse-like incident plane wave by means of experiments or simulation, and then make convolution of the coupled voltage and the excited voltage. So that rE, the field-distance product, will be acquired by multiplying the convolution result with a certain constant. It was observed that while the opening angle and azimuth angle of the TEM horn were kept unchanged, the value of rE growed larger as the length of the two conducting plates of the horn increased. If the volume of the TEM horn scaled up, the amplitude of second-time radiation pulse, resulting from mismatch between the impedance of the TEM horn and free space, stayed the same, but the delay between the second-time radiation and the main pulse increased, which equaled to 2*l/c, where l was the length of the TEM horn´s conducting plate and c the speed of light.