A new design of TEM horn antenna based on ultra-wide band broken line

TEM horn antenna is a kind of ultra-wide band antennas. Ultra-wide band antenna can make a pulse signal have minimum distortion through radiation, namely the smaller the impulse response trailing is. TEM horn antenna radiate TEM spherical wave. It is limited by center of antenna port and the edge phase difference, so generally it requires a small horn flare angle. There are many loads in the TEM horn antenna to reduce low frequency reflection and absorb some low frequency energy. TEM horn antenna with a small field angle can be approximated as electrical dipole antenna in a low frequency. And loading low frequency compensation circuits can constitute a magnetic dipole, so electric dipole and magnetic dipole forms a combination oscillator antenna, which can improve the low frequency radiation performance of antenna. Taking power capacity and caliber match into consideration, we design a new TEM horn antenna based on ultra-wide band broken line. Compared to traditional constant impedance TEM horn antenna, the new design has better performance, on account for the fact that the new TEM horn antenna adopts transitional feed-in structure in coaxial panel, and the radiation plate is separated into two broken line forms. By theoretical simulation and experimental research, we compare and analyze the input, radiation characteristics of two kinds of antenna. Results indicate that when width of Gaussian pulse excitation is 960 ps, the transition peak power transmission efficiency of coaxial panel will reach at 85%. Peak electric field radiation of new TEM horn antenna improves by 30% than constant impedance horn. Main lobe width of H aside pattern decreases to 60° noticeably compared with original 80°. In addition, it perfects transmission radiation characteristics in 700MHz band, transient pulse peak power capacity comes to 15GW.