Dual-Polarized 6–18-GHz Antenna Array With Low-Profile Inverted BoR Elements

This article investigates a dielectric-loaded Vivaldi-type antenna array that is formed inside a plastic block. It utilizes the inverted body-of-revolution (BoR) structure, where cone-shaped cavities are formed in a dielectric material and metalized from the inside. The metalized cavities form an array of inverted BoR elements that are fed by a single printed circuit board. In contrast to previous work, this paper uses a solid, shaped plastic block instead of foam as a dielectric material and exploits its considerably higher permittivity to reduce the height of the elements. The reduced profile provides an excellent polarization purity in the class of tapered slotline (TSL) antennas while a 3:1 bandwidth is maintained with an active reflection coefficient (ARC) $\leq -10$ dB. The shaping of the dielectric block decreases the scan loss of the array and prevents detrimental surface waves. The proposed array can steer the beam up to ± 50° in all planes without exceeding −10 dB ARC. The proposed dielectric loading may be applied also to other antenna types, such as conventional BoR antennas. The excellent electrical performance and manufacturability of the array are confirmed by fabricating and measuring a prototype.