An ultra-wideband non-metal horn antenna , comprising: an impedance matching member comprising a first end and a second end opposite to each other, wherein the first end of the impedance matching member comprises a first tenon portion , and an end surface of the second end of the impedance matching member is provided with a first recessed structure , wherein the first recessed structure comprises a first protruding portion and a first groove structure surrounding the first protruding portion ; a field adjustment member , which comprises a first end and a second end opposite to each other, wherein an end surface of the first end of the field adjustment member is provided with a first trench structure , and an end surface of the second end of the field adjustment member is provided with a second recessed structure , wherein the second recessed structure comprises a second protruding portion and a second groove structure surrounding the second protruding portion , and a top surface of the second protruding portion is provided with a second trench structure corresponding to the first tenon portion , and the first tenon portion of the impedance matching member is inserted into the second trench structure of the field adjustment member ; and an outer cover member , which comprises a first tapered structure and a second tenon portion corresponding to the first trench structure , wherein the first tapered structure comprises a vertex angle (A1, A2) and a bottom surface , the second tenon portion is connected to the bottom surface of the first tapered structure , and the second tenon portion of the outer cover member is inserted into the first trench structure of the field adjustment member . an impedance matching member comprising a first end and a second end opposite to each other, wherein the first end of the impedance matching member comprises a first tenon portion , and an end surface of the second end of the impedance matching member is provided with a first recessed structure , wherein the first recessed structure comprises a first protruding portion and a first groove structure surrounding the first protruding portion ; a field adjustment member , which comprises a first end and a second end opposite to each other, wherein an end surface of the first end of the field adjustment member is provided with a first trench structure , and an end surface of the second end of the field adjustment member is provided with a second recessed structure , wherein the second recessed structure comprises a second protruding portion and a second groove structure surrounding the second protruding portion , and a top surface of the second protruding portion is provided with a second trench structure corresponding to the first tenon portion , and the first tenon portion of the impedance matching member is inserted into the second trench structure of the field adjustment member ; and an outer cover member , which comprises a first tapered structure and a second tenon portion corresponding to the first trench structure , wherein the first tapered structure comprises a vertex angle (A1, A2) and a bottom surface , the second tenon portion is connected to the bottom surface of the first tapered structure , and the second tenon portion of the outer cover member is inserted into the first trench structure of the field adjustment member . <EOS>