A Directive Subminiature Antenna for High-Power Ultrawideband Pulse Radiation

Abstract

This letter presents a compact directive antenna to radiate a high-power ultrawideband (UWB) pulse. The proposed antenna is composed of a modified biconical-based radiator (electric dipole), magnetic dipoles, a feedthrough insulator, and a coaxial cable. The electrical size of the antenna is <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$0.195{\lambda _L} \times 0.195{\lambda _L} \times 0.176{\lambda _L}$</tex></formula> ( <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">${\hbox{width}} \times {\hbox{height}} \times {\hbox{length}}$</tex> </formula> ), where <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\lambda _L}$</tex></formula> is the wavelength corresponding to the lowest frequency of the bandwidth. The fabricated antenna realizes a bandwidth of 0.207–2.60 GHz (12.56:1) and a far-voltage of 131.3674 kV with a front–back ratio of 22.72 dB. The antenna is designed to radiate a <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$\pm 75~\hbox{kV}$</tex></formula> amplitude bipolar pulse with a 0.83-ns pulse width through the frequency band from 0.207 to 2.33 GHz.