Free-space measurement of bi-axial anisotropic materials
This paper presents an extension of the free-space method for measurement of bi-axial anisotropic material at microwave frequencies. In this method, four complex transverse constitutive parameters are directly computed from the reflection and transmission coefficients of a planar sample in free space for a normally incident plane wave with two polarizations. By using the measured amplitudes of the reflection and transmission coefficients of a planar sample at six incident angles with two polarizations, two complex longitudinal constitutive parameters are obtained by finding the solution to minimize the properly designed objective function under the suitable judging criterion. The numerical trials are carried out for a high-loss material by joining random errors to simulate the real measurement condition, which verifies the validity of this method.
A free-space method for measurement of dielectric constants and loss tangents at microwave frequencies
For measurements of dielectric properties of planar slabs of ceramic and composite materials, the authors have developed a free-space measurement system in the frequency range of 14.5-17.5 GHz. The key components of the measurement system are a pair of spot-focusing horn lens antennas, a network analyzer, and a computer. Because of the far-field focusing ability of horn lens antennas, the free-space measurements can be made at microwave frequencies in a relatively compact and simple measurement setup. The time-domain gating feature of the network analyzer and the thru, reflect, and line calibration technique were used to eliminate the effects of undesirable multiple reflections. The dielectric constants and loss tangents were measured for standard materials such as fused quartz, Teflon, and polyvinylchloride (PVC). Dielectric properties for Teflon and PVC were also measured in a waveguide medium for purposes of comparison with the free-space method. >
Barbarians, Gentlemen and Players : A Sociological Study of the Development of Rugby Football
Part I: Folk Antecedents and Transitional Forms of Football in the Public Schools 1. The folk antecedents of modern rugby and their decline 2. Football in the early 19th century public schools Part II: The Modernisation of Rugby Football 3. The preconditions for modernization: embourgeoisement and public school reform 4. The incipient modernization of rugby football 5. The 'civilising process' and the formation of the RFU. 6. The democratization of rugby football. 7. Professionalisation and the amateur response. 8. The split. 9. The class structure and the professionalisation of British sport. Part III: The Development of Rugby Football as a Modern Sport 10. The professionalisation of rugby league. 11. Rugby union as a modern sport: bureaucracy, gate-taking clubs and the swansong of amateurism. Conclusion: Sociological Reflections on the Crisis in Modern Sport