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Orthogonality, Power Flow and Waveguide Losses
Published in Edward F. Kuester, Theory of Waveguides and Transmission Lines, 2020
For a quasi-TEM mode on a structure containing only air and one other uniform dielectric region (the substrate, with subscript i = 1 which will be dropped here), we have α≃ω2μ0ϵ0ϵeffqϵ″ where q=∂ϵeff∂ϵr and εeff is to be evaluated at (the real value of) εr. Equation (9.43) should be compared to the small loss limit of the attenuation coefficient (8.70) of a TEM mode: αTEM≃ω2μϵ′ϵ″ For microstrip for instance, the wider the line is, the closer to 1 the filling factor will be, and the larger the attenuation coefficient for a given value of ε″. Qualitatively, however, dielectric losses for quasi-TEM modes are very similar to those of pure TEM modes.
Visual acuity response when using the 3D head-up display in the presence of an accommodation-convergence conflict
Published in Journal of Information Display, 2020
The transparent retroreflective screen was fabricated by partially patterning an optically clear glass with retroreflective microspheres. By controlling the filling factor of retroreflective microspheres, the screen provides 50%–75% transparency and up to 10 times the brightness provided by a regular non-transparent diffused screen [19]. Figure 2(b) shows a 75% transparent screen displaying a virtual dashboard imagery. The stereo views projected by the two pico projectors are separated through the retroreflective property of the screen, while the stereo crosstalk is minimized by the polarization maintainability of the retroreflective microspheres.