All‐dielectric circularly polarised loop antenna made of high‐permittivity ceramic/water

Abstract A kind of all‐dielectric circularly polarised (CP) loop antenna made of high‐permittivity material is proposed. The leaky‐wave radiation from a high‐permittivity dielectric waveguide is utilised here to support the operation of the proposed antenna. A non‐closed dielectric loop covering a three‐quarter circle is adopted to generate CP radiation and it is connected with the dielectric ground via one of bending ends to form an all‐in‐one structure of the antenna. The other end is also bent and vertical to the ground, but hanging in the air for probe feed. As two kinds of typical high‐permittivity dielectric materials, zirconia ceramic and pure water are used to implement the proposed design respectively. On one hand, an all‐ceramic CP loop antenna made of zirconia is proposed. And benefiting from the low loss and high melting point of zirconia, the proposed ceramic antenna has superiority in radiation efficiency and could adapt to a harsh environment. On the other hand, by using pure water and transparent container, a fully‐transparent CP water loop antenna can be obtained. Finally, a 3‐D printing technology is adopted in the manufacturing of ceramic structure and resin container. Measured results of both antennas demonstrate the validity of the proposed design.