Ultrawideband Microwave Biconical High-Gain Antenna for Dual-Band Systems of Omnidirectional Radio Monitoring

Abstract

This paper presents a new ultrawideband omnidirectional microwave biconical antenna having gain above 10 dB that has been proposed, developed, optimized and experimentally tested. The main feature of the developed biconical antenna is its possible use in uniaxial dual-band systems of omnidirectional radio monitoring. The possibility of arranging two omnidirectional antennas having different operating frequency bands on a single axis is provided by feeding a biconical antenna via a coaxial transmission line, the inner conductor of which contains another coaxial line for feeding the second antenna with smaller size conductors. For ensuring a high gain of biconical antenna (above 10 dB at diameter 21λ0), the antenna design included an axial-symmetric dielectric lens designed for equalizing the phase front at the aperture in the ultrawideband of frequencies with bandwidth ratio 2.3:1. The use of optimal dielectric lens makes it possible to achieve the same value of gain at the antenna diameter, which is 5 times as small as the one in the absence of lens. The veracity of theoretical results obtained is confirmed by a good agreement of calculated characteristics with measured ones for the developed prototype of biconical antenna. The proposed ultrawideband omnidirectional biconical antenna can be recommended for application in the state-of-the-art and future advanced systems of omnidirectional radio monitoring, radio intelligence, data transmission, and radio countermeasures.