The invention discloses a double resonance oscillation circular polarization and short back reflection C waveband antenna. The double resonance oscillation circular polarization and short back reflection C waveband antenna uses a multifunctional spurious coupling array mode, and is characterized in that a reflection cavity is of a cylindrical structure with one end sealed, an antenna substrate is located at the bottom of the interior of the reflection cavity, an antenna array of a square corner cut shape is etched at the center of the antenna substrate, a plurality of spurious array pieces are evenly distributed along the circumference of the antenna array, the reflection cavity achieves an antenna pointing energy convergence radiation function, the spurious array pieces achieve electromagnetic coupling, fixation support and antenna substrate positioning functions, a reflection plate is fixedly connected with an open end of the reflection cavity, a round reflector piece is pasted at the center of the reflection plate, the reflection plate is parallel and opposite to the antenna array, a radio frequency connection piece is located at the center of the outer end of the reflection cavity, one end of the radio frequency connection piece is fixedly connected with a cable, and the other end of the radio frequency connection piece passes through the reflection cavity and is connected with the antenna array. The double resonance oscillation circular polarization and short back reflection C waveband antenna is simple in structure, has the advantages of being wide in main lobe, low in side lobe, portable and small, and is suitable for satellite communications, navigation communications and ground anti-interference communications.