A three-dimensional (3-D) propagation model, combined with a patched-wall model, has been developed to predict radio loss in a corridor environment. The ray-tracing technique is used and combined with the ray-fixed coordinate system to simplify the computations of transmission, reflection, and diffraction coefficients in 3-D space. The computed path loss is compared with the measured value of 900-MHz and 2.44-GHz radio propagation along a hallway and gives a reasonable agreement. It is also found that the fields transmitted through the interior walls give the major contribution to the received field when the radio path lies around a corner.

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Abstract-A new design of multiband quasi-Yagi type antenna for 700 MHz band, GSM900, DCS1800, GPS, and Bluetooth/WLAN applications is presented. In contrast to conventional quasi-Yagi antenna design, our proposed antenna realizes the multiband performance by interaction between the section extended ground and the derived driver element which is a branch of driver dipole element. The parametric studies of the proposed antenna are discussed to explore the antenna operating mechanism. The performances of the antenna are demonstrated along with measured and simulated results.Index Terms-700 MHz band, antenna, multiband antenna, quasi-Yagi antenna.

A novel filtering diplexing antenna for dual-band operation is presented. The antenna is composed of a slot-loaded patch and two resonators with a commonly used ground. Dog-bone-shaped slots are used on the ground for achieving broadside magnetic coupling and increasing the isolation between operating bands. The antenna design is based on a second-order Chebyshev bandpass filter synthesis. The proposed antenna exhibits high band-edge selectivity performance, low cross-polarization levels with half-power beamwidths greater than 86° for 2.4-and 5.2-GHz WLAN communication bands. The measured and simulated results are highly consistent.Index Terms-band-edge selectivity, Chebyshev bandpass filter, diplexer, filtering diplexing antenna.

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In holographic data storage systems, it is straightforward to increase the storage capacity by mean of reducing the pitches among data symbols. However, this may lead to severe inter-symbol interference (ISI) and also unacceptable data error rate. To deal with the problem, we first model the channel as a partial response (PR) and use the maximum-likelihood (ML) detection to control the ISI. The Viterbi decoder is employed to implement ML detection.

A square-looped and an end-coupled resonator used in a planar ultra-wideband (UWB) antenna to achieve bandnotched performance are presented here. To obtain notched performance in the wireless local area network band, both the square-looped and end-coupled resonator are designed and placed in a fork-shaped UWB antenna centre. The characteristics and schematic equivalent circuit of each resonator are also discussed. Parametric studies of a fork-shaped antenna with square-looped resonator are given as an example to explore the operating mechanism. Accordingly, the band-notched antenna can effectively select target bands by adjusting different resonator structures. The proposed antenna features flat gainfrequency response and group delay as well as 10-25 dB gain suppression in the notched band.

This study reports the fabrication of the high-quality hafnium dioxide (HfO2) film at room temperature (20–30 °C) using the neutral beam enhanced atomic layer deposition (NBEALD) we developed. The HfO2 film was fabricated using tetrakis(ethylmethylamino)hafnium (TEMAH) as the Hf precursor and O2 NB as the oxidant. Argon gas was used for the carrier and purge gases. The HfO2 film-deposition process consists of 5-s TEMAH feed, 5-s Ar purge, 5-s O2 gas injection, 20-s O2 neutral beam irradiation, and 5-s Ar purge. The HfO2 film exhibited a saturated growth per cycle of 0.18 nm/cycle and a high-quality film with low C contamination (2.7%), N contamination (3.9%), and a good O/Hf ratio (2.0) was achieved. The film also had an ideal refractive index of 1.9. Additionally, continuously grown high-quality HfO2 and silicon dioxide (SiO2) gate oxide films (stacked HfO2/SiO2 gate oxide film) were successfully fabricated at room temperature. This film has the potential to decrease the thermal budget, thus enabling high flexibility when designing semiconductor structures. These findings demonstrate the effectiveness of our NBEALD in forming high-k gate stack structures.