Miniaturized single feed point dual-frequency and dual-polarization microstrip antenna

The invention relates to a miniaturized single feed point dual-frequency and dual-polarization microstrip antenna. The upper surface of a substrate base plate is provided with a first radiation patch and a second radiation patch; the first radiation patch and the second radiation patch are chamfering patches which are symmetrically chamfered in a diagonal position; the second radiation patch is annular, the first radiation patch is positioned in a cavity of the second radiation patch, and the first radiation patch and the second radiation patch have a same center; the lower surface of the substrate base plate is provided with a conduction grounding plate; coaxial probe feed vertically penetrates through the substrate base plate and is directly connected with the first radiation patch to generate electric coupling, and the second radiation patch is electromagnetically coupled with the first radiation patch. The invention realizes dual-frequency circular polarization, has the characteristics of small size, low section, simple manufacture process, low cost, favorable axial ratio bandwidth and higher low-elevation gain and can be used for a high-performance satellite navigation systemreceiver. Meanwhile, the requirements of vehicle-carried equipment on the volume and weight of the antenna can be met.