This studyproposes a novel compact dielectric dual-polarized waveguide antenna. By usingdielectric materials, the physical dimensions of conventional air-filled waveguides can be effectively reduced. To mitigatestrong back-lobe radiation, this study proposes a method of designingrectangular slots on waveguide walls, theoperating principlesof which are similar to that of choke-ring structures. Compared to choke rings, the proposed rectangular slots exhibitseveral advantages;theyhave a simple structure and compact sizeand are easy to fabricate. Through full-wave simulation analyses, the proposed antenna was found to operate ata wide impedance bandwidth greater than 40% andexhibited a high gain of 8.6±0.6 dBi;it also demonstrated stable radiation performance over the operating bandwidth. These advantages imply that the proposed antenna can be used for various applications in X-band frequencies, such as satellite communication.