Array antenna and millimeter wave radar

The embodiment of the utility model relates to the technical field of antennas, in particular to an array antenna and a millimeter wave radar, and the array antenna comprises a dielectric substrate, an antenna array and a combining device. A first input port, an output port, a second input port and an isolation port are sequentially arranged on the combining device; the antenna array comprises at least two antenna array units, the output port is connected with the at least two antenna array units through the feed transmission line, and the at least two antenna array units are symmetrically arranged relative to the output port; the isolation port is connected with the signal isolation unit; when input signals with the same amplitude and the same phase are input to the first input port and the second input port, the input signals are combined through a channel of the combining device, then gained output signals are output to the antenna array through the output port, and the antenna array transmits the gained o