Analyzing the power coupled between partially coherent waveguide fields in different states of coherence.
J Opt Soc Am A Opt Image Sci Vis 19:7 (2002) 1376-1382
Abstract:
A procedure is described for calculating the power coupled between partially coherent waveguide fields that are in different states of coherence. The method becomes important when it is necessary to calculate the power transferred from a distributed source S to a distributed load L through a length of multimode metallic, or dielectric, waveguide. It is shown that if the correlations between the transverse components of the electric and magnetic fields of S and L are described by coherence matrices M and M', respectively, then the normalized average power coupled between them is (eta) = Tr[MM']/Tr[M]Tr[M'], where Tr denotes the trace. When the modal impedances are equal, this expression for the coupled power reduces to an equation derived in a previous paper [J. Opt. Soc. Am. A 18, 3061 (2001)], by use of thermodynamic arguments, for the power coupled between partially coherent free-space beams.Microwave transmission through high-temperature superconducting waveguides
Physica C: Superconductivity and Applications 372-376 (2002) 532-525
Report of the first prototype of non-imaging focusing heliostat and its application in high temperature solar furnace
Solar Energy Elsevier 72:6 (2002) 531-544
Non-linear two-frequency analysis of SIS mixers through harmonic balance
J PHYS IV 12:PR3 (2002) 165-168
Abstract:
We present a numerical procedure for simulating the non-linear behaviour of Superconductor-Insulator-Superconductor (SIS) tunnel-junction mixers. Mixers of this kind are used extensively in high-performance submillimetre-wave astronomical receivers. The procedure is complete in that both the signal and local-oscillator voltages can be at high levels, with significant amounts of harmonic content; also, the full quantum mechanical behaviour of the tunnel junction is taken into account. The initial simulations show that multi-tone analysis can be carried out in a numerically efficient manner, and that saturation, and the attendant generation of IF harmonics, can be modelled rigorously. This work constitutes the first full non-linear model of an SIS mixer, arid the theoretical and numerical procedures described, will be of great importance when designing the next generation of heterodyne astronomical receivers.A two element horn-reflector antenna for cosmic microwave background astronomy
IEEE Transactions on Antenna and Propagation 50 (2002) 198-204