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In recent decades, the calibration-independent methods have successfully been employed to determine the complex permittivity of dielectric materials without the need of calibration before measurements. However, these methods experience their respective problems from the requirement of two samples, the movement of the sample, or the introduction of extra assistant transmission lines. To eliminate these problems, a simple method is proposed based on transmission/reflection method in this paper. This method can afford high accurate measurement results without singularities by only two measurements of uncalibrated scattering parameters with one sample and one line. One measurement is for the empty fixture and the other for the same fixture holding the sample at a single position. Additionally, the principle of the proposed method ensures it independent of the fixture and the sample position. Some experiments were made using the vector network analyzer 8753ES and a Φ 16-mm coaxial line fixture. The proposed method is validated by the measurements of the permittivity of polytetrafluoro ethylene from 2 to 6 GHz.

A simple experimental method to determine the initial complex permeability of the toroidal type ferrite core using thoroughly designed fixtures is introduced. With the ferrite core installed in a shorted coaxial line, the fixture forms a one turn coil of inductor or a shorted transmission line with distributed parameters. The relative permeability of the ferrite can then be extracted from S/sub 11/ of the coaxial test holder with the aid of a vector network analyzer. The "one turn coil" modeling method for radio frequencies (RF), and the transmission line modeling method for higher frequencies, are described. To improve the measurement accuracy of the test system, the subsidiary RF resistors and impedance matching circuits are integrated into the fixtures. Test results of the proposed methods achieve good agreement with the results of the traditional transmission/reflection method and the Agilent E4991A material analyzer. The influence of air gap on accuracy is discussed, as well as the upper frequency limit due to cavity resonance. Compared with some existing studies, this method achieves satisfactory accuracy and can be accomplished with normal instruments.

Two test systems are constructed to give verification of SAE-ARP-1173-2004 and MIL-DTL-83528C-2001 for evaluation of the conductive gaskets. Test frequency ranges are 400 Hz-400 MHz and 20 MHz-10 GHz respectively. Typical test results for several different types of gaskets are given. The technical details of these two methods are compared and discussed.

It is studied in detail that the influences of EUT with different properties on the reverberation chamber performances. Different amounts of absorbers have been added to load the chamber. It is found suitable amount of load may increase the chamber performance but more absorbers may decrease it. The influences of metal EUT on performance of a chamber have been studied by placing different size of metal enclosure in chamber. It is found a big size metal EUT deteriorate the performance though the load is small.

A three-dimensional cubical-grid FDTD code is used to look at unloaded field patterns versus frequency in a TTEM cell to 150 MHz. An experimental field mapping (x, y, z components) of the TTEM cell has been performed for important sections. Very good agreement is shown between measured and computed transverse plan field uniformity. The transverse electromagnetic characteristics of the cell are also discussed.

Serial connection of an LC filter and a microwave absorption filter can achieve good interference suppression performance from 10 kHz to 10 GHz, but the suppression ability of the filter is insufficient above 10 GHz. /spl lambda//4 short and open circuit transmission lines are used to construct a reflection filter, to improve the interference suppression ability of the filter above 10 GHz, specifically between 8 GHz and 18 GHz.

Transmission/reflection frequency-domain measurements to determine the electromagnetic properties of solid materials in a coaxial line are introduced in this essay. The method can determine both the complex relative permittivity (/spl epsiv//sub r/) and permeability (/spl mu//sub r/) simultaneously. A few problems such as half-wavelength divergence, phase jump, multiplicity of roots etc. have been discussed. As sample materials, the derived /spl epsiv//sub r/ and /spl mu//sub r/ of teflon and some absorbers are given and the accuracy of the test system is described. The advantage of this system is to determine the electromagnetic properties of absorptive materials.

The finite-difference time-domain (FD-TD) method is applied to calculate the distribution of electric and magnetic field in Triple-TEM (T-TEM) cell that has been made in our EMC laboratory. A few important problems are studied carefully, such as: the simulation of wave source, the resistance plane and absorbing materials as terminal load at the back of the cell, the absorbing boundary conditions etc. The procedure for calculation is compiled in C++ language. The calculation results are analyzed carefully.