Abstract: With the development of terahertz technology, higher requirements have been placed on the resolution, integration, and power consumption of on-chip imaging systems. On-chip antenna technology was a crucial approach to realize the integration of antennas and circuits, it offered advantages such as compact structure and high reliability. However, on-chip antennas faced challenges such as narrow bandwidth and low gain. Meanwhile, for terahertz imaging chips, the configuration of antenna arrays was equally important as the performance of antenna elements, it necessitated the achievement of high gain, low coupling, and side-lobe suppression. This paper designed on-chip patch antenna elements and arrays for terahertz imaging applications based on complementary metal oxide semiconductor technology. By loading slots, we achieved antenna elements with a 11.8% fractional bandwidth, the gain of antenna arrays reached 10.6 dBi with the efficiency of 21.9%, it satisfied the demands of terahertz imaging applications. We integrated terahertz antenna arrays with circuits, a compact terahertz imaging array chip has been realized, whose radiation performance of the transceiver arrays meets the requirements for terahertz imaging applications.