In this thesis, we propose a new bandwidth-enhancement method of using a parasitic open slot to achieve a wide lower band for the internal laptop computer antenna with a small size to cover the GSM850/900 operation and a wide upper band to cover the GSM1800/1900/UMTS operation as well. The occupied antenna volume is only 48 ¡Ñ 10 ¡Ñ 3.5 mm^3 above the top edge of the display ground. For practical application, we analyze the effects of the antenna position, nearby metal plate, shielding metal plate, keyboard ground, FR4 substrate, and the size of display ground on the performance of the WWAN antenna. In addition, effects of the user¡¦s whole-body on the proposed antenna are also analyzed. Owing to the user¡¦s whole-body being mainly lossy materials, a decrease in the antenna¡¦s radiation efficiency is observed when the user¡¦s whole-body is in close proximity to the WWAN laptop computer antenna.

The operation speed of power delivery system of packages has been upgraded to GHz. The instant current will pass to the power plane of the mother board by way of the IC pins and result in electromagnetic wave propagation between the power plane and the ground plane, then to produce the programs of electromagnetic interference. In this thesis, we will analyze the EMI of power delivery system of packages by finite-difference time-domain in two dimensions structure in three sections. In firist section, to computing EMI in finite-difference time-domain in two dimensions structure. In second section, to analyze more complicated power delivery plane, ex: EBG, in finite-difference time-domain in two dimensions structure. In three section, to add property of capacitors on power plane to reduce EMI in two dimensions structure. Above all, we hope to built a fast computing method to compute EMI to solve the time-consuming problems of full-wave simulated software. And to supply the engineer to deal with the similar problems in packages efficiently.

Advances in micro-sensor and wireless technology enable small but smart sensors to be developed for wide range environment-monitor applications. Since Sensor nodes only have limited power capacity and are difficult to recharge, how to prolong network lifetime is an important issue in wireless sensor networks design. Several topology control algorithms have been proposed to maintain the connectivity of wireless sensor network and reduce the energy consumption. Multi-hop Infrastructure Network Architecture (MINA) is a kind of Multi-layer Architecture for WSN topology, which utilizes hundred of sensors to transmit data to a sink. This architecture partitions sensor nodes into layers based on their distances (calculated by hop count) to BS. In this way, the node connected to more nodes will relay more data for other nodes. This make the node exhaust its battery power quickly and thus reduces the network lifetime. This study proposes an Efficient Energy Time-Slot Allocation (EETA) scheme which distributes time slots in accordance with the energy of neighbor nodes and the number of neighbor nodes. In addition, this work also devises an adaptive time slot size to reduce data packet drop in case when the node buffer is full. The simulation results show that the EETA performs better than the MINA in terms of network lifetime.

In this thesis, two novel broadband slot mobile phone antenna designs respectively for penta-band WWAN operation and eight-band LTE/WWAN operation are presented. The antennas are suitable to be mounted near the bottom edge of the system ground plane of the mobile phone. Good radiation characteristics for the antennas are obtained, and the two antennas respectively occupy a small printed area of 50 ¡Ñ 4 mm2 and 53 ¡Ñ 4 mm2. The first design uses a C-shaped strip connected to the bottom edge of the system ground plane to make the structure of the system ground plane close to a symmetric shorted dipole antenna. This makes it promising to excite a chassis mode to enhance the operating bandwidth of the antenna. The second one uses a microstrip feedline having a chip-inductor-loaded branch. The novel microstrip feedline can lead to more uniform distribution of the electric fields excited in the slot such that enhanced bandwidth of the antenna¡¦s lower band is obtained. Further, since the chip inductor performs like a low-pass filter, the original bandwidth of the antenna¡¦s upper band is not affected. Additionaly, the impedance matching of the lower frequencies of the upper band can be improved, which enhances the upper-band bandwidth of the antenna. Effects of the user¡¦s head and hand on the proposed antenna are also studied, and the simulated SAR and HAC issues are also analyzed in this thesis.

This work studies the allocation of bandwidth resources in wireless ad hoc networks. The highest-density clustering algorithm is presented to promote reuse of the spatial channel and a new slot allocation algorithm is proposed to achieve conflict-free scheduling for transmissions. Since the location-dependent contention is an important characteristic of ad hoc networks, in this paper we consider this feature of ad hoc networks to present a new cluster formation algorithm, by increasing the number of simultaneous links to enhance spatial channel reuse. Furthermore, because each cluster has its own scheduler and schedulers operate independently of each other, the transmissions may conflict among the clusters. In this paper, we classify the flows by the locations of their endpoints to prevent this problem. Finally, the proposed mechanism is implemented by simulation and the results reveal that the conflicts can be efficiently avoided without global information and the network throughput is improved without violating fairness.

A six-band antenna design for the mobile phone is presented. The required bandwidth for DTV/GSM850/900/DCS/PCS/UMTS operation is achieved by using two antennas. For DTV/GSM850/900 operation, we propose a novel antenna by using the concept of the dipole antenna and an internal matching portion to excite the half- and one-wavelength resonant modes of the antenna. With the internal matching portion, the frequency ratio of the two resonant modes can be controlled, thereby making the two resonant modes formed into a very wide operating band. For DCS/PCS/UMTS operation, a novel monopole slot antenna is used. The lower-edge frequency of the slot antenna depends on its length and the required bandwidth can be achieved by adjusting its tuning section. Effects of casing and human body on the proposed mobile phone antenna are also discussed. It is found that the radiation efficiency of DTV/GSM bands is larger than that of DCS/PCS/UMTS bands in this design. However, overall the operating bands, the antenna performances are greatly affected when the human effects are taken into considerations.

FlexRay is a new automotive network communication protocol for control and interconnection among ECUs (electronic control units) in the cluster. In the FlexRay protocol, a communication cycle consists of static segment and dynamic segment. The static segment is a TDMA scheme designed for transmitting time-triggered messages. Due to its determinism and reliability, it is particularly applicable to X-by-wire applications. Each static slot is allocated to a specified task and the task can transmit message during the exclusive slot. However, if the task has no message to transmit during its assigned slot, the slot cannot be used by other tasks. The overall utilization is low if the bandwidth requirement of each task is not high. To improve the system utilization, we apply the real-time scheduling techniques to devising a deterministic, static cyclic scheduling. The objective is to reduce the demand on the number of static slots needed for scheduling time-triggered tasks. Specifically, we treat the set of static slots that are in the same position in every communication cycle as an individual real-time channel. We model each task as a real-time task, specified by (Ci,Ti). It requires that for every Ti communication cycles, the system must allocate at least Ci time slots to satisfy the real-time constraint of the task. We decompose each such task into a set of subtasks, allocate them to the real-time channels and then apply the rate-monotonic scheduling algorithm to schedule the subtasks within each channel. Finally, we perform computer simulation to evaluate the effectiveness of our proposal. From the simulation results, we conclude that our proposal is able to effectively reduce the demand for the static slots under a wide range of real-time requirements.

In industrial drives market, speed and position estimation are one of the most important subjects for accurate motor drives. Vector controlled drives has the best dynamic performance among AC motor drives. Sensorless vector control is one of the most studied one. However, sensorless drive systems fail at low or zero speeds and may not have enough accuracy. For better accuracy and speed range speed sensors or position encoders are usually essential. However, coupling of sensor and sensor prices introduces extra cost on the drive. Thus in order to reduce the cost of the drive a cheap and easy to mount speed sensor is essential. Throughout this study, a speed and position sensor using an external search coil placed between cooling fins on the frame of an induction machine is proposed. The search coil utilizes the fringing flux outside the frame of induction motor. Using the induced voltage on the external search coil, a new method that estimates the flux and rotor position is proposed. In this study, the induced voltage on the search coils are investigated with different types of search coils placed on various positions. The frequency domain and time domain analysis are performed in order to build a model that can estimate machine flux, rotor speed and rotor position. As a result of this study, a low cost, easy to mount speed and position sensor is designed and implemented. Experiment results are presented.

The aim of this study is to investigate the effects of changes in the physical parameters of tapered slot antennas (TSA) on their radiation characteristics and also to explore the possibility of reconfiguration in the radiation pattern of TSA by switching between two different types of tapering. There are mainly three physical parameters that affect the radiation pattern of TSAs. These are antenna length, aperture width and the ground extension. After designing a wideband microstrip line to slot line transition, the effect of antenna parameter variations on the beamwidth and sidelobe level of the antenna are investigated through the use of a commercially available electromagnetic simulation software HFSS by ANSOFT. The radiation characteristics of constant width slot antennas (CWSA) and linearly tapered slot antennas (LTSA) are compared. It is observed that CWSAs exhibit narrower beamwidth and higher sidelobe level whereas linearly tapered slot antennas (LTSA) have wider beamwidth with lower sidelobe level compared to each other. A novel switching architecture between CWSA and LTSA is proposed to obtain a reconfigurable antenna.

The bandwidth-enhancement characteristics of slot-loaded rectangular microstrip antennas constructed on a thin microwave substrate have been investigated in this dissertation. The primary design process about this topic is demonstrated. Firstly, a new antenna design idea is provided from pre-determined antenna design specifications or obtained antenna performances from the previous antenna design, which lead to a novel antenna configuration. From the results of the simulation software IE3DTM, the characteristics of this new antenna configuration are obtained and compared with the experimental results. The antenna configuration is also modified to achieve a final optimal design from the comparison results. The study of the single-feed dual-frequency rectangular microstrip antenna with a pair of bent slots is first presented. By embedding properly-designed slots on a rectangular microstrip patch, the impedance characteristics of this antenna design have been effectively changed to exhibit dual-resonant behavior, which result in the excitation of two adjacent resonant modes with similar radiation characteristics. Furthermore, the two resonant modes can be excited at frequencies very close to each other to form a wider operating bandwidth by embedding additional perturbation slots. Four successful antenna designs with different embedded-slot shapes for bandwidth enhancement have been implemented and discussed in this dissertation.