Shuming T. Wang

A six-antenna station based indoor positioning system

This study develops an intelligent wireless indoor positioning system (IPS), which includes new beam antenna design and modified probabilistic neural network based positioning algorithm. The six directional antennas can obtain the angle between an object and the station. Then, a modified probabilistic neural network is applied to estimate the accurate position of the object with the signal strength. The developed IPS architecture has the average error of less than 0.8 meters in the eight square meter indoor scene. This indoor positioning scheme is not only has high positioning accuracy, but also can be an effective solution to solve the difficult issue of positioning station deployment.

The Transmittance Estimation of Touch Panel Decoration Film by Neural Network

In this paper, a transmittance estimator of touch panel decoration film by using neural network is presented. In the evaporation process, the coating material and the related control parameters are all important influencing factors in obtaining the desired transmittance. The relationship among the transmittance and these factors are very complex and nonlinear. It’s very hard to use the certain mathematical model to describe such relationship. In this research, the neural network was employed to catch the relationship among transmittance and its possible influencing factors. In other words, an efficiently and precisely automatic evaporation parameters decision system for touch panel decoration film is expected to be developed. Through the estimation system developed, the quality of transmittance of touch panel film could meet the customer’s requirement.

Design of a PA controller for a quad-band cell phone

A controller which was applied in a power amplifier module for a quad-band cell phone was designed and fabricated in this paper. This controller provides the required DC bias voltage of the quad-band amplifier so that the output of the amplifier reaches the specific power level under various battery output. In addition, a decoder circuit was also included. The outputs of the decoder were used to manage switches so that the power amplifier can operate at different frequency bands, DCS or GSM, and modes, transmission or receiving.

Analysis of Acoustic Wave Property on AlN/Diamond/Si Thin Film Substrates

Multi-layer piezoelectric thin-film substrates which may present properties of good temperature characteristic, high reflectivity, high coupling coefficient, high phase velocity, and integrated with semiconductor, have the potential to replace single crystal piezoelectric substrates used on acoustic devices. The properties of piezoelectric thin-film substrates are determined by the structures of the substrates, the piezoelectric material, the metal film thickness and etc. Usually the acoustic wave parameters of the substrates are not readily obtainable from literature. In this paper, the acoustic wave properties of thin film substrate of AlN/Diamond/Silicon were analyzed using finite element method. The research data of this paper would be applied to design high frequency RF acoustic devices such as resonators and filters.

A New Technique for Searching the Global Minimum of Supervised Neural Network

This paper presents a technique in how to searching the global minimum for the supervised neural network training. This technique is developed based on the idea of nearly equivalent model. To demonstrate the new technique proposed, two signal processing studies, including signal recognition and signal modeling were simulated. For a comparison, the same simulations were also performed by using the neural network with the standard steepest descent error back-propagation (BP) algorithm. From the simulation results shown, the technique we proposed not only can evidence whether the neural network is in the local training or not, but also can show that the “best” performance of the neural network should have.

The predictions of optoelectronic attributes of LED by neural network

In this paper, the predictions of optoelectronic attributes of Light-Emitting Diode (LED) chip, including luminous intensity, wavelength and forward voltage by using neural network were presented. The simulated data was measured by Electrical Luminescence (EL) technique. The well-trained neural models were used to predict the optoelectronic attributes of LED chip in its epitaxy growth stage in advance. These predicted results could provide the necessary information for the process engineer to adjust the control parameters of epitaxy growth accurately and then ensure the LED chip to be in conformance with the requested quality.

A High P1dB GSM RF Switch in Electronic Engineering

In order to meet the high RF power capabilities by the requirements of mobile communication system, two types of high P1dB GaAs PHEMT quad-band RF switch are designed and implemented in this paper. One has adopted three-gate-finger method and the other uses only single gate but with extra gate length. Both switches possess qualities of low insertion loss, high degree of isolation, and low noise. Their output P1dB at the bands of 820 to 920 MHz as well as 1720 to 1920 MHz are measured and compared.

Design of the crescent-shape planar ultrawideband antenna with a band-notch structure

A miniaturized crescent-shape planar antenna is proposed for ultra-wideband applications. The proposed antenna consists of a trapezoid ground plane and a crescent-shape radiating patch with a symmetrically circular slot inside the patch. The antenna is fabricated on an FR4 with a thickness of 0.8 mm and the relative permittivity of 4.4. Simulated results show that the return loss (VSWR <; 2) covers the UWB spectrum and the radiation patterns are highly similar to a dipole antenna. To avoid an interference with the present existing bands such as IEEE 802.11a (5.15 GHz-5.825 GHz), UWB systems are required a band-notched feature. Usually, this can be achieved by a band-notched filter integrated with the UWB antenna. In this study, a nested slot band-notched filter is adopted and the filter can block the signal between 5 GHz to 6 GHz. Simulated results such as VSWR, radiation pattern, and current distribution are also described.

An intelligent data mining technique for the estimations of TP film's chromatic aberration

This paper presents a novel intelligent data mining technique to estimate the optical properties of touch panel (TP) with different layers coating. The neural network (NN) model is developed to be the intelligent tool for the data analyzer. The new computational method based on well-trained NNs weights is used to analyze the influencing factors of TP films chromatic aberration, i.e. L.a.b. values. The influence degree of each input variable to the net output could be determined through the computational results. The useful and important information for TP films chromatic aberration then can be obtained. In this research, the data of TP film with Cr and Cr2O3 coating are studied. All possible influencing factors are collected and considered. An artificial intelligent (Al) estimator using the best influencing factors is expected to be developed so that the optical properties of TP decoration film could be precisely estimated before the evaporation process is taken.

Analysis of acoustic wave property on ZnO/Diamond/Si thin film substrates

Multi-layer piezoelectric thin-film substrates which may have the properties of good temperature characteristic, high reflectivity, high coupling coefficient, high phase velocity, and integratible with semiconductor, have the potential to be used on acoustic devices. The properties of piezoelectric thin-film substrates are determined by the structures of the substrates, piezoelectric material, the metal film thickness and etc. Usually the acoustic wave parameters of the substrates are not readily obtainable from literature. In this paper, the acoustic wave properties of ZnO/Diamond/Silicon substrate was analyzed using finite element method. The data of this paper would be applied to design high frequency RF acoustic devices such as resonators and filters.