A Wideband, Miniaturized Millimeter-Wave Fabry–Pérot Cavity Antenna Without Independent Partially Reflective Surface Enabled by Dielectric-Filled-Shape-Cavity

In this article, a compact Fabry–Pérot cavity (FPC) architecture with a simple structure is introduced for millimeter-wave (mmW) application. This is the first attempt to apply a dielectric-filled-shape-cavity (DFSC) as the cavity of an FPC antenna. By utilizing the discontinuity of permittivity between the dielectric and air, an intrinsic partial reflection effect can be formed without an extra partially reflective surface (PRS), which is commonly required by a conventional FPC. At the same time, due to the relatively high dielectric of the DFSC, antenna size can be significantly miniaturized. Furthermore, we modified the structure of DFSC to form a reverse-stepped shape, contributing to bandwidth and gain enhancement of the FPC antenna. The proposed antenna consists of only two components, a feeding antenna and the proposed DFSC. The size of the antenna is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\lambda _{0}$ </tex-math></inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$ 4\lambda _{0}$ </tex-math></inline-formula>, which is much smaller when compared with recently reported FPC-type of antennas. For demonstration, the antenna was designed, manufactured, and measured. The measured results show that the working bandwidth of the antenna is 15.9%. It yields a peak gain of 18.3 dBi, and in-band radiation pattern is stable. The proposed antenna has superior advantages in terms of size, bandwidth, and simplicity.