Wideband Endfire 3-D-Printed Dielectric Antenna With Designable Permittivity

This letter presents a three-dimensionally (3-D)-printed low-profile endfire dielectric antenna with wideband performance. The proposed device comprises four dielectric sections that are designed with tapered permittivities and sizes to achieve impedance-matched surface-wave launching over a wide bandwidth. The effective permittivity of dielectric blocks is precisely controlled within the range of 2.0 to 8.3 through varying the infill factor of the 3-D printing process. The relation between permittivity and infill factor has been experimentally validated and compared against Bruggeman effective medium approximation theory. Experimental results show that the proposed antenna exhibits a wide impedance bandwidth of 57.7 $\%$ from 6.9 to 12.5 GHz, a low tilt angle of around 20 $^\circ$ over the endfire direction, and a high realized gain above 10 dBi from 7.2 to 12.5 GHz. All these findings demonstrate that 3-D printing technology can be leveraged to conveniently fabricate sophisticated antennas with controllable material properties.