Front end design of 8mm polarimetric microwave radiometer

A front end of 8mm polarimetric microwave radiometer is presented in this paper. Simulations and measurements have shown that it has a good performance. The actual measured results show that it has an impedance bandwidth of VSWR<;1.25 over 35GHz-39GHz, within which the two ports isolation is lower than -39dB, the gain of it is larger than 21.6dBi and the sidelobe level is less than -20dB. For the advantages mentioned above, it could be used in measuring the sea surface wind vector. As an important aspect, the methods to design ortho-mode transducer (OMT) and multimode horn (MMH) are discussed in this paper.