A tunable slot loop antenna loaded with interdigitated ferroelectric varactors at multiple positions is designed, fabricated, and measured. Measurement results show that the resonant frequency of the proposed antenna can be tuned from 15.18 GHz to 15.36 GHz as the bias voltage is increased from 0 V to 39 V.

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The parallax exists because the camera is set to the periphery of display in current videoconference. In this paper, we proposed a new system to eliminate this parallax by aligning user, transparent display and camera in the same axis. And we also adjusted the key parameters to take into account of camera and display. Author KeywordsParallax-free; transparent display; videoconference; Objective and backgroundDue to the traditional LCD use the opaque backlight module, the camera is set to the periphery of LCD. In this arrangement, the parallax issue between user and camera while in the videoconference always confuses the user. It is because the user used to look at the display rather than look at the camera, as shown in Fig.1 (a).On the other hand, the transparent LCD (T-LCD) becomes popular in LCD technology because it could show stylish and elegant images and bring a completely new visual experience to attract people's attention [1,2]. Therefore we combined T-LCD and camera to propose a new videoconference system by aligning user, T-LCD and camera in the same axis to eliminate the parallax issue, as shown in Fig.1 (b). there is no mutual gaze because the camera is in the edge of LCD (b) videoconference by using transparent display; there is mutual gaze because the camera is behind the transparent display Experimental ResultsIn order to achieve the parallax-free videoconference system, a transparent light guide was used to replace traditional opaque backlight module. A transparent backlight module could also improve the blur issues by removing the optical films. We developed the transparent light guide with scattering function as the conventional diffuser and prism [3]. The side light type transparent light guide could provide an uniform R-G-B backlight for display as shown in Fig. 2. Besides, to improve the image quality of parallax-free videoconference system, a color filter-less LCD with fieldsequential-color (FSC) driving was used to increase display transmittance and reduce diffraction phenomenon.. The resulting transmittance of the color-filter-less T-LCD could be improved from 5% to 15%. The experiment scheme is shown in Fig.3. The camera was behind the transparent light guide to capture image, and the distance between color filter-less LCD and target was 300 mm.Timing sequence of the camera exposure and the RGB LEDs were set to 4.16ms, respectively, as shown in Fig. 4. According to the timing chart, display images of the T-LCD could be seen while the RGB LEDs were turned on and the camera could capture the image of target through the T-LCD only while the camera shutter was turned on.

Silicon on insulator (SOI) substrate is a key materials for nano-scaling IC device and the requirement for its crystal structure and quality is really high. Nanothick silicon thin film can be transferred onto a handle wafer from a donation wafer to form a SOI wafer after this process including hydrogen implantation of donation wafer, wafer bonding, and thermal treatment at moderately high temperatures of 400 to 600 degree centigrade. The expansion of the hydrogen molecular evolving from the implanted hydrogen ions interacting with silicon dangling bonds and trapped inside the microcavities located near the ion projected range resulted in exfoliation of the silicon thin film in the final heating step. The hydrogen molecules inside the microcavities tend to expand along the bonded interface rather than radially to form individual blisters. Finally, the fracture failure of ion implanted area parallel to the bonded interface near the projected ion range is formed by the sideway expansion of the cavities due to the diffusion supply of implanted hydrogen excited by thermal energy. Microwave processing can lower the activity energy to speed the chemical reaction so that it leads the format of microcavities occurring at low temperature by directly exciting the implanted hydrogen ions by microwave energy and also results in decreasing the critical dosage for layer splitting. However, microwave irradiation alone at room temperature causes the formation of lots of nucleus sites of micro-voids filled by hydrogen molecule which is immobility in silicon resulting in the issue of uniformity of transferred layer. In this study, the hydrogen implanted silicon substrate was irradiated by microwave at low temperature (200 degree centigrade) rather than microwave alone to co-activate the implanted hydrogen ions in silicon to increase not only kinetic energy but also mobility to successfully achieve a completely transferred layer in a short time.