The band structure of a photonic crystal slab is analyzed by the finite-element method. Here, a curvilinear mixed-interpolation-type triangular-prism element is proposed so as to express cylindrical air holes of a photonic crystal slab smoothly enough in fewer elements. The numerical results are presented to show the usefulness of the analysis method.
We propose a new type of re-writable bitmap image display component using the MEMS (Micro Electro Mechanical Systems) -controlled light scattering. The device is made of a light-guided transparent substrate (glass) and a thin sheet of semi-transparent plastic film (PDMS; Poly Di Methyl Siloxane) with magnetic nickel and light-diffusing glass powders formed in an electrostatic parallel-plate actuator. The membrane segment under a moderate drive voltage (110V), is designed to suspend itself at the rest position over the glass substrate, in which an illumination light travels at the condition of internal total reflection. When an extra force is applied for instance, by manually pressing with a glass rod (diameter 1mm), the membrane is electrostatically brought into contact with the glass substrate, where the light scatters through the membrane to the eyes of a viewer. The trace of the glass-rod stroke persists in the membrane as long as the driving voltage is applied. The image can also be partially erased by magnetically pulling up the magnetic membrane using a tiny permanent magnet scanned over the device. In other words, the developed device has a function of blackboard to which the bitmap image data is written manually. Thanks to the simplicity of the structure and operation principle, the device can be made in large area by the recent “Large Area MEMS” such as a roll-to-roll printing, inkjet printing and plastic molding.
A new simple method is proposed for evaluating the magnetic antenna factor of an electrically small loop antenna. Generally the magnetic antenna factor is defined in far field condition. However it is difficult to realize the far field condition and propagate electromagnetic waves by electrically small antennas when the frequency range is less than 30MHz. Though some methods are proposed before, they have difficulty to realize the abovementioned matters. In the proposing method, the magnetic antenna factor of a loop antenna can be evaluated only by measuring the input impedance and loop radius because an electrically small loop antenna's characteristic is dominated by Faraday's law and the impedance in the relevant frequency range. So the evaluation does not need to require quantities related to other transfer characteristics of transmitting and receiving antennas.