Design Of Novel Ortho_Mode Transducer For Microwave Antennas

In recent years, with the rapid development of communications,microwaverelay communication antennas are constantly developing and improving. Microwavecommunication system functions mainly through fiber optic transmission network,terrestrial microwave, satellite and other aerial communication to complete.Microwave transmission system from the use of new technologies and transmissioncapacity perspective, a new generation of SDH synchronous digital microwavecommunication system replaces the traditional sense of the PDH microwavecommunication. In order to adapt to the new communication from the SDHmicrowave frequency reuse of development, the use of dual_polarized frequencyreuse is the most economical and easiest methods to achieve, so that we are requiredto develop high_performance dual_polarized antennas.The traditional dual_polarized microwave antennas and two curved reflectingsurface, the waveguide feed composition, its complex structure, making difficult,poor performance, high cost and small diameter can not be achieved,andlow_polarized and other disadvantages, so as modern microwave antenna designtools and simulation equipment constantly updated and improved, regardless of thecurrent dual_polarized microwave antenna aperture size has been transformed by thefollowing two parts: a unipolar dual reflector antenna and Ortho_modetransducer(OMT). The program’s dual_polarized antenna completely avoidable oldforms a series of problems caused by the antenna, and the design of the antenna isalso fulfill with ETSI proposed Class3standards. But this scenario traditional designtheory to design a OMT also has a complex structure,difficult process,productdefects and poor reliability.The topic of this thesis is “Design of Novel Ortho_Mode Transducer ForMicrowave Antennas”. We analyze the basic theory and implementation principal ofOMT, in conjunction with the experience of actual production process, clever use ofrectangular waveguide(circular waveguide) transmission line and the main modecutoff frequency and electric field distribution characteristics, converter andwindows coupled design principles, we are able to use simulation software and acombination of actual debugging developed a new form of polarization splitter formicrowave antenna with new design method. Moreover, this new form of OMT has alow VSWR and high isolation characteristic which fulfill the microwave antennausage requirement. In this thesis, we will use this design principles and methods to design15GHzOMT,and Finally, we put the sample into test and gain a remarkable test result. Inconclusion, we determine the feasibility of this new form of polarization splitter.This new form of polarization splitter offers us a good foundation for completion ofthe full microwave antenna series and the wide usage of dual polarization antennas.