The number of wireless communication applications increase steadily, leading to the competition for currently allocated frequency bands. Pressure on authorities around the world to permit communications in higher and wider frequency ranges to achieve higher wireless capacity than those existed in the past has resulted in several new specifications. The federal communication commission (FCC) in USA has unleashed the band 3.1-10.6 GHz for ultra-wideband radio (UWB) communications. The release has triggered a worldwide interest for UWB. Other regulatory instances throughout the world have issued use of UWB techniques as well. Capacity issues in form of data rate and latency have always been a bottleneck for broadened wireless-communication usages. New communication systems like UWB require larger bandwidth than what is normally utilized with traditional antenna techniques. The interest for compact consumer electronics is growing in the meantime, creating a demand on efficient and low profile antennas which can be integrated on a printed circuit board. In this thesis, some methods to extend the bandwidth and other antenna parameters associated with wideband usages are studied. Furthermore, methods on how to enhance the performance when one antenna-element is not enough are studied as well. The principle of antenna parallelism is demonstrated using both microstrip patch antennas and inverted-F antennas. Several techniques to combine the antennas in parallel have been evaluated. Firstly, a solution using power-splitters to form sub-arrays that covers one 500-MHz multi-band orthogonal frequency division multiplexing (OFDM) UWB is shown in Paper I. It is then proposed that the sub-bands are selected with a switching network. A more convenient method is to use the later developed frequency multiplexing technique as described in Paper V and VIII. Using the frequency multiplexing technique, selective connection of any number of antennas to a common junction is possible. The characteristic impedance is chosen freely, typically using a 50-Ω feed-line. Secondly, in Paper VIII a frequency-triplexed inverted-F antenna system is investigated to cover the Mode 1 multi-band UWB bandwidth 3.1-4.8 GHz. The antenna system is composed of three inverted-F antennas and a frequency triplexer including three 5th order bandpass filters. In Paper VI a printed circuit board integrated-triplexer for multi-band UWB radio is presented. The triplexer utilizes a microstrip network and three combined broadside- and edge-coupled filters. The triplexer is fully integrated in a four metal-layer printed circuit board with the minimum requirement on process tolerances. Furthermore, the system is built completely with distributed microstrips, i.e., no discrete components. Using the proposed solution an equal performance between the sub-bands is obtained. Finally suitable monopoles and dipoles are discussed and evaluated for UWB. In Paper X circular monopole and dipole antennas for UWB utilizing the flex-rigid concept are proposed. The flex-rigid concept combines flexible polyimide materials with the regular printed circuit board material. The antennas are placed entirely on the flexible part while the antenna ground plane and the dipole antenna balun are placed in the rigid part.

Ubiquitous computing and Internet-of-Things (IoT) implies an untapped opportunity in the realm of information and communication technology, in which a large number of micro-devices with communication and/or computing capabilities, provides connectivity for anything, by anyone at anytime and anywhere. Especially, these devices can be equipped with sensors and actuators that interact with our living environment. Barcode, smart contactless card, Radio Frequency Identification (RFID) systems, wireless sensor network (WSN), and smart mobile phones are some examples which can be utilized in ubiquitous computing. RFIDs and WSN have been recognized as the two promising enablers for realization of ubiquitous computing. They have some great features such as low-cost and small- size implementation, non-line of sight operation, sensing possibilities, data storing ability, and positioning. However, there are several challenges which need to be addressed, such as limited life time for battery powered device, maintenance cost, longer operation range, higher data rate, and operation in dense multipath and multiuser environment. Ultra-Wideband Impulse Radio (UWB-IR) with its huge advantages has been recognized as a great solution for future WSN and RFID. UWB-IR technique has the possibility of achieving Gb/s data rate, hundreds of meter operation range, pJ energy per bit, centimeter accuracy of positioning, and low cost implementation. In this work utilization of UWB-IR in WSN and RFID is investigated. A wireless sensor network based on UWB-IR is proposed focusing on low-cost and low-power implementation. Our contribution is to imply two different architectures in base station and sensor nodes to satisfy power, complexity and cost constraints. For sensor nodes, an autonomous UWB-IR detection is proposed, which detects the UWB signal autonomously and no restrict synchronization is required. It reduces the circuit complexity significantly. The performance in term of bit-error-rate is compared with two other common detection techniques. It is shown that the new detection is more robustness to timing jitter and clock skew, which consequently reduces the clock and synchronization requirements considerably. A novel wireless sensing and identification system, based on remote-powered tag with asymmetric wireless link, is proposed. Our innovative contribution is to deploy two different UWB and UHF communication techniques in uplink and downlink respectively. In the proposed system, tags capture the required power supply from different environmental sources (e.g. electromagnetic wave transmitted by a reader) and transmit data through an ultra-low power impulse UWB link. A new communication protocol is devised based on slotted-aloha anti-collision algorithm. By introducing several improvements including of pipelined communication, adaptive frame size, and skipping idle slots, the system throughput of more than 2000 tags/s is achieved. To prove the system concept a single chip integrated tag is implemented in UMC 0.18μm CMOS process. The measurement results show the minimum sensitivity of -18.5 dB (14.1 μW) and adaptive data rate up to 10 Mb/s. It corresponds to 13.9 meters operation range, considering 4W EIRP, a matched antenna to the tag with 0dB gain, and free space path loss. This is a great improvement in operation range and data rate, compared with conventional passive RFID, which data rate is limited to a few hundreds of Kb/s. System integration in a Liquid-Crystal-polymer (LCP) substrate is investigated. The integration of a tunable UWB-IR transmitter and a power scavenging unit are studied. Our contribution includes embedding and modeling the RF components and antenna in substrate and co-optimizing the chip and package with on-chip versus off-chip passives trade-offs. Simulation results verify the potential of system-on-package solution for UWB integration. The effect of antenna miniaturization in a UWB system is studied. Our focus is to scale down a UWB antenna and optimize the performance through the chip-antenna co-design. A tunable impulse- UWB transmitter is designed in two cases - a conventional 50Ω design and a co-design methodology. The simulation results show that the standard 50Ω design technique can not reach the best condition in all cases, when a real antenna is placed into the system. The performance can be improved significantly when doing codesign. The antennas and UWB transmitter performances are evaluated in a given UWB systems. It is shown that the operation distance at a target performance is reduced with antenna scaling factor and it can be compensated by antenna-transceiver co-design. The result proves the importance of antenna-transceiver codesign, which needs to be addressed in the earliest phases of the design flow. / QC 20100701

In general, ultra wideband (UWB) signals are transmitted using ~'eIYshort pulses m tiIae domain, thus promising very high data rates. In this thesis, a recei'ler structure is proposed for decoding multiuser information data in a convolutionally coded UWB system. The proposed iterative receiver has three stages: a pulse detector, a symbol detector, and a channel decoder. Each of these stages outputs soft values, which are used as a priori information in the next iteration. Simulation results show that the proposed system can provide performance very close to a single-user system. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical and Computer Engineering. / "July 2006." / Incluldes bibliographic references (leaves 29-31)

Ultra-wideband (UWB) is an appealing transmission technology for short-range, bandwidth demanded wireless communications. With the data rate of several hundred megabits per second, UWB demonstrates great potential in supporting multimedia streams such as high-definition television (HDTV), voice over Internet Protocol (VoIP), and console gaming in office or home networks, known as the wireless personal area network (WPAN). While vast research effort has been made on the physical layer issues of UWB, the corresponding medium access control (MAC) protocols that exploit UWB technology have not been well developed. Given an extremely wide bandwidth of UWB, a fundamental problem on how to manage multiple users to efficiently utilize the bandwidth is a MAC design issue. Without explicitly considering the physical properties of UWB, existing MAC protocols are not optimized for UWB-based networks. In addition, the limited processing capability of UWB devices poses challenges to the design of low-complexity MAC protocols. In this thesis, we comprehensively investigate the MAC protocols for UWB networks. The objective is to link the physical characteristics of UWB with the MAC protocols to fully exploit its advantage. We consider two themes: centralized and distributed UWB networks. For centralized networks, the most critical issue surrounding the MAC protocol is the resource allocation with fairness and quality of service (QoS) provisioning. We address this issue by breaking down into two scenarios: homogeneous and heterogeneous network configurations. In the homogeneous case, users have the same bandwidth requirement, and the objective of resource allocation is to maximize the network throughput. In the heterogeneous case, users have different bandwidth requirements, and the objective of resource allocation is to provide differentiated services. For both design objectives, the optimal scheduling problem is NP-hard. Our contributions lie in the development of low-complexity scheduling algorithms that fully exploit the characteristics of UWB. For distributed networks, the MAC becomes node-based problems, rather than link-based problems as in centralized networks. Each node either contends for channel access or reserves transmission opportunity through negotiation. We investigate two representative protocols that have been adopted in the WiMedia specification for future UWB-based WPANs. One is a contention-based protocol called prioritized channel access (PCA), which employs the same mechanisms as the enhanced distributed channel access (EDCA) in IEEE 802.11e for providing differentiated services. The other is a reservation-based protocol called distributed reservation protocol (DRP), which allows time slots to be reserved in a distributed manner. Our goal is to identify the capabilities of these two protocols in supporting multimedia applications for UWB networks. To achieve this, we develop analytical models and conduct detailed analysis for respective protocols. The proposed analytical models have several merits. They are accurate and provide close-form expressions with low computational effort. Through a cross-layer approach, our analytical models can capture the near-realistic protocol behaviors, thus useful insights into the protocol can be obtained to improve or fine-tune the protocol operations. The proposed models can also be readily extended to incorporate more sophisticated considerations, which should benefit future UWB network design.

Ultra-wideband (UWB) technology and its use in imaging and sensing have drawnsignicant interest in the last two decades. Extensive studies have contributed toutilize UWB transient scattering for automated target recognition and imagingpurposes. In this thesis a near-eld UWB synthetic aperture radar (SAR) imagingalgorithm is presented.It is shown with measurements and simulation, that it is possible to reconstruct an imageof an object in the near eld region using UWB technology and SAR imaging algorithm.However the nal SAR image is highly aected by unwanted scattered elds at each pixelusually observed as an image artifact in the nal image. In this study these artifactsare seen as a smile around the main object. Two methods are suggested in this thesiswork to suppress this artifact. The rst method combines the scattered eld informationreceived from both rear and front of the object to reconstruct two separate images, onefrom rear view and one from front view of the object respectively. Since the scatteredelds from behind the object are mirrored, the pixel by pixel multiplication of thesetwo images for objects with simple geometry will cancel the artifact. This method isvery simple and fast applicable to objects with simple geometry. However this methodcannot be used for objects with rather complex geometry and boundaries. Thereforethe Range Point Migration (RPM) method is used along with the global characteristicsof the observed range map to introduce a new artifact rejection method based on thedirectional of arrival (DOA) of scattered elds at each pixel. DOA information can beused to calculate an optimum theta for each antenna. This optimum angle along withthe real physical direction of arrival at each position can produce a weighting factor thatlater can be used to suppress the eect of undesired scattered elds producing the smileshaped artifact. Final results of this study clearly show that the UWB SAR accompaniedwith DOA can produce an image of an object free of undesired artifact from scatteredeld of adjacent antennas.

Ultra Wideband Radio (UWB) is an upcoming alternative for wireless communications. Since the Federal Communication Commission in the USA allowed UWB for unlicensed usage in April 2002, more and more companies have started developing UWB systems. The major difference with UWB compared to other RF systems is that UWB sends information with pulses instead of using a carrier wave. The technique is from the nineteenth century and was first developed by Heinrich Hertz (1857-1894), which led to transatlantic communications 1901. This Master thesis presents a proposal of a transmitter for Ultra Wideband Radio using multiple bands. The proposed transmitter is implemented on system level in Simulink, Matlab. The frequency generation in the transmitter is also implemented at component level in a 0.13 um IBM process. The thesis begins with an introduction of UWB theory and techniques.

Ultra-wideband (UWB) is an appealing transmission technology for short-range, bandwidth demanded wireless communications. With the data rate of several hundred megabits per second, UWB demonstrates great potential in supporting multimedia streams such as high-definition television (HDTV), voice over Internet Protocol (VoIP), and console gaming in office or home networks, known as the wireless personal area network (WPAN). While vast research effort has been made on the physical layer issues of UWB, the corresponding medium access control (MAC) protocols that exploit UWB technology have not been well developed. Given an extremely wide bandwidth of UWB, a fundamental problem on how to manage multiple users to efficiently utilize the bandwidth is a MAC design issue. Without explicitly considering the physical properties of UWB, existing MAC protocols are not optimized for UWB-based networks. In addition, the limited processing capability of UWB devices poses challenges to the design of low-complexity MAC protocols. In this thesis, we comprehensively investigate the MAC protocols for UWB networks. The objective is to link the physical characteristics of UWB with the MAC protocols to fully exploit its advantage. We consider two themes: centralized and distributed UWB networks. For centralized networks, the most critical issue surrounding the MAC protocol is the resource allocation with fairness and quality of service (QoS) provisioning. We address this issue by breaking down into two scenarios: homogeneous and heterogeneous network configurations. In the homogeneous case, users have the same bandwidth requirement, and the objective of resource allocation is to maximize the network throughput. In the heterogeneous case, users have different bandwidth requirements, and the objective of resource allocation is to provide differentiated services. For both design objectives, the optimal scheduling problem is NP-hard. Our contributions lie in the development of low-complexity scheduling algorithms that fully exploit the characteristics of UWB. For distributed networks, the MAC becomes node-based problems, rather than link-based problems as in centralized networks. Each node either contends for channel access or reserves transmission opportunity through negotiation. We investigate two representative protocols that have been adopted in the WiMedia specification for future UWB-based WPANs. One is a contention-based protocol called prioritized channel access (PCA), which employs the same mechanisms as the enhanced distributed channel access (EDCA) in IEEE 802.11e for providing differentiated services. The other is a reservation-based protocol called distributed reservation protocol (DRP), which allows time slots to be reserved in a distributed manner. Our goal is to identify the capabilities of these two protocols in supporting multimedia applications for UWB networks. To achieve this, we develop analytical models and conduct detailed analysis for respective protocols. The proposed analytical models have several merits. They are accurate and provide close-form expressions with low computational effort. Through a cross-layer approach, our analytical models can capture the near-realistic protocol behaviors, thus useful insights into the protocol can be obtained to improve or fine-tune the protocol operations. The proposed models can also be readily extended to incorporate more sophisticated considerations, which should benefit future UWB network design.

Characteristics of wireless home and office services and the corresponding networking issues are discussed. Local Area Networking (LAN) and Personal Area Networking (PAN) technologies such as IEEE 802.11 and Ultra Wideband (UWB) are introduced. IEEE 802.11a and UWB systems are susceptible to interference from each other due to their overlapping frequencies. The major contribution of this work is to provide a framework for coexistence of the two systems. The interference between the two systems is evaluated theoretically by developing analytical models, and by simulations. It is shown that the interference from UWB on IEEE 802.11a systems is generally insignificant. IEEE 802.11a interference on UWB systems, however, is very critical and can significantly increase the bit error rate (BER) and degrade the throughput of the UWB system. A novel idea in the MAC layer is presented to mitigate this interference by means of temporal separation. Simulation results validate our technique. Implications to wireless home services such as high definition television (HDTV) are provided. Future research directions are discussed.

The objective of this thesis is aimed at the design of low noise amplifier (LNA) for an ultra-wideband (UWB) receiver system using standard 0.18um CMOS process. A two amplified stage topology is proposed in the low noise amplifier. The first stage introduces inductively source degeneration, it can achieve wideband input impedance matching. The second stage introduces traditional CS configuration, it can improve the forward gain (S21). The second stage also used L-C section for output match. In order to improve the gain at high frequency, we introduces the series peaking between the first stage and second stage. We use the resistive-feedback between second stage and output, it can achieve wideband output impedance matching. The total power dissipation of the low noise amplifier is about 16.5mW at power supply 1.5 volt and the chip size is 920*940mm2. The simulated result shows that S11 is under -9dB, S22 is under -10dB, the forward gain S21 is 11.63dB~12.56dB at 3.1-10.6GHz, the reverse isolation S12 is under -32dB, and the noise figure is3.3dB~3.96dB.

The research of this thesis is on the mobile TV antenna designs. There are three antenna designs proposed in this thesis. The first two designs are for portable TV sets. They are different from the traditional straight monopole antenna because the two proposed designs can be built-in with the portable TV set. The third one is for laptop applications. It can be stored inside a laptop when the antenna is not in use, and can be pulled out of the laptop when in operation. Thus the proposed antenna will not affect the appearance of the laptop.