Circular microwave ablation antenna and system

A circular microwave ablation system, comprising a circular microwave ablation antenna, wherein the circular microwave ablation antenna comprises a needle head, a needle bar, a coaxial cable, a conduit, and a choke ring;

• the circular microwave ablation antenna is provided with a chamber, the chamber accommodates the coaxial cable and the conduit, a water inlet channel is disposed between the conduit and the coaxial cable, and a water return channel is disposed between the conduit and the needle bar;
• the chamber and the conduit extend forward to a front end of the circular microwave ablation antenna, and an antenna emission window is located in the conduit to enable a cooling medium to cool an area of the antenna emission window;
• a part of the conduit in a microwave emission area is made of a microwave permeable material, so that a microwave radiates outward, and the rest of the conduit is made of a microwave shielding material;
• the choke ring is located at a rear side of the microwave emission area and is hermetically fixed to the conduit, so that the choke ring blocks the microwave, a gap is provided between the choke ring and the needle bar for a backflow of the cooling medium, wherein the needle head is a metal head, a tail of the metal head protrudes backward, and an inner conductor of the coaxial cable is connected to the tail of the metal head;
• the antenna emission window is formed between a rear end of the metal head and a front end of an outer conductor of the coaxial cable;
• and wherein the choke ring is directly contacting an external wall of the conduit in a region between the conduit and the needle head.