Measurement Of Properties Of Microwave Materials By Transmission/Reflection Algorithm Based On Rectangular Waveguide Over K&Ka Band

This project mainly describes a method for obtaining the complex permittivity andpermeability of microwave materials over K-band&Ka-band range of microwave frequencies.Improve the existing NRW transmission/reflection algorithm, and through MATLAB programmer,calculate the electromagnetic parameters of the medium to be measured by the known scatteringmatrix, which the matrix comes from simulation software HFSS.First introduce the electromagnetic parameters test system model and components, anddetermine to use rectangular waveguide of BJ220-type and BJ320-type over the test frequencyband17GHz~26GHz and26GHz~40GHz. Then, deduce the classical NRW transmission/reflection method, based on the theoretical analysis of the algorithm in the presence of multi-valueproblems and the thickness resonance problems, and puts forward the corresponding solutions.Two improved algorithms respectively in the K-band and Ka-band to research the multi-valueproblems and thickness resonance problems of NRW transmission/reflection method. Mainly tostudy on the problems in the algorithm of dielectric constant of the dielectric material in the K-band.There are three equations in the different situations, which impedance and propagation constantnormalized characteristic derived independent of each other, to realize measurement preciselypermittivity of non-magnetic material; In the Ka-band, validate the system with the air as medium,meanwhile solute the multi-value problems. Then, use the teflon as a medium for measurement, anddiscuss the thickness resonance problem. For the nonmagnetic material, with value of r rinsteadof the value of r, not only improves the accuracy of measurement, but also eliminate the thicknessresonance.Electromagnetic parameters of the uniaxial anisotropic medium are measured by improvedNRW transmission/reflection algorithm. When electromagnetic wave propagate along the principalaxis direction in the medium, is identical with the electromagnetic wave propagation in isotropicmedium, so can obtain the permittivity tensor of materials by the transmission/reflection method.