Approved for public release, distribution is unlimited / Presently, the required data file to be loaded onto the Radar Warning Receiver (RWR) onboard the F-16 aircraft is done manually by the aircraft technicians, two to three hours prior to the actual flight time. This process should be automated. As such there is a need to look into the use of wireless transmission technology to complement or replace the manual method of loading the critical data file from the command station onto every F-16 aircraft. The present wireless technology is relatively mature and stable. In this thesis, the feasibility of incorporating and adapting this technology for use in the flight line environment is examined. The propagation effect in wireless transmission is also studied and recommendations proposed with regards to the installation of wireless facilities in the flight line. In addition, the EDNA, a portable maintenance aid that comes with the F-16 aircraft for loading the data file, has to be upgraded. Hence, a system feasibility study is carried out to adapt or upgrade the present equipment to wireless transmission capability. / Major, Republic of Singapore Air Force

As one of the major building blocks in a wireless receiver, the Analog-to-Digital Interface (ADI) provides link and transition between the analog Radio Frequency (RF) frontend and the baseband Digital Signal Processing (DSP) module. The rapid development of the radio technologies raises new design challenges for the receiver ADI implementation. Requirements, such as power consumption optimization, multi-standard compatibility, fast settling capability and wide signal bandwidth capacity, are often encountered in a low voltage ADI design environment. Previous research offers ADI design schemes that emphasize individual merit. A systematic ADI design methodology is, however, not suffciently studied. In this work, the ADI design for two receiver systems are employed as research vehicles to provide solutions for different ADI design issues. A zero-crossing demodulator ADI is designed in the 0.35µm CMOS technology for the Bluetooth receiver to provide fast settling. Architectural level modification improves the process variation and the Local Oscillation (LO) frequency offset immunity of the demodulator. A 16.2dB Signal-to-Noise Ratio (SNR) at 0.1% Bit Error Rate (BER) is achieved with less than 9mW power dissipation in the lab measurement. For ADI in the 802.11b/Bluetooth dual-mode receiver, a configurable time-interleaved pipeline Analog-to-Digital-Converter (ADC) structure is adopted to provide the required multi-standard compatibility. An online digital calibration scheme is also proposed to compensate process variation and mismatching. The prototype chip is fabricated in the 0.25µm BiCMOS technology. Experimentally, an SNR of 60dB and 64dB are obtained under the 802.11b and Bluetooth receiving modes, respectively. The power consumption of the ADI is 20.2mW under the 802.11b receiving mode and 14.8mW under the Bluetooth mode. In this dissertation, each step of the receiver ADI design procedure, from system level optimization to the transistor level implementation and lab measurement, is illustrated in detail. The observations are carefully studied to provide insight on receiver ADI design issues. The ADI design for the Ultra-Wide Band (UWB) receiver is also studied at system level. Potential ADI structure is proposed to satisfy the wide signal bandwidth and high speed requirement for future applications.

Emerging technologies such as Bluetooth and 802.11b (Wi-Fi) have fuelled the growth of the short-range communication industry. Bluetooth, the leading WPAN (wireless personal area network) technology, was designed primarily for cable replacement applications. The first generation Bluetooth products are focused on providing low-cost radio connections among personal electronic devices. In the WLAN (wireless local area network) arena, Wi-Fi appears to be the superior product. Wi-Fi is designed for high speed internet access, with higher radio power and longer distances. Both technologies use the same 2.4GHz ISM band. The differences between Bluetooth and Wi-Fi standard features lead to a natural partitioning of applications. Nowadays, many electronics devices such as laptops and PDAs, support both Bluetooth and Wi-Fi standards to cover a wider range of applications. The cost of supporting both standards, however, is a major concern. Therefore, a dual-mode transceiver is essential to keep the size and cost of such system transceivers at a minimum. A fully integrated low-IF Bluetooth receiver is designed and implemented in a low cost, main stream 0.35um CMOS technology. The system includes the RF front end, frequency synthesizer and baseband blocks. It has -82dBm sensitivity and draws 65mA current. This project involved 6 Ph.D. students and I was in charge of the design of the channel selection complex filter is designed. In the Bluetooth transmitter, a frequency modulator with fine frequency steps is needed to generate the GFSK signal that has +/-160kHz frequency deviation. A low power ROM-less direct digital frequency synthesizer (DDFS) is designed to implement the frequency modulation. The DDFS can be used for any frequency or phase modulation communication systems that require fast frequency switching with fine frequency steps. Another contribution is the implementation of a dual-mode 802.11b/Bluetooth receiver in IBM 0.25um BiCMOS process. Direct-conversion architecture was used for both standards to achieve maximum level of integration and block sharing. I was honored to lead the efforts of 7 Ph.D. students in this project. I was responsible for system level design as well as the design of the variable gain amplifier. The receiver chip consumes 45.6/41.3mA and the sensitivity is -86/-91dBm.

Submitted by Programa de P?s-Gradua??o Engenharia El?trica (ppgee@ifpb.edu.br) on 2018-04-17T16:59:08Z No. of bitstreams: 1 43- Thamyris da Silva Evangelista - DESENVOLVIMENTO DE SUPERF?CIE SELETIVA EM FREQU?NCIA RECONFIGUR?VEL BASEADA NA GEOMETRIA ESTRELA DE QUATRO BRA?OS PARA APLICA??O EM 2,4 GHz.pdf: 3077852 bytes, checksum: e604c3a3df9471f48941fe95027e6ad2 (MD5) / Approved for entry into archive by Programa de P?s-Gradua??o Engenharia El?trica (ppgee@ifpb.edu.br) on 2018-04-17T17:00:16Z (GMT) No. of bitstreams: 1 43- Thamyris da Silva Evangelista - DESENVOLVIMENTO DE SUPERF?CIE SELETIVA EM FREQU?NCIA RECONFIGUR?VEL BASEADA NA GEOMETRIA ESTRELA DE QUATRO BRA?OS PARA APLICA??O EM 2,4 GHz.pdf: 3077852 bytes, checksum: e604c3a3df9471f48941fe95027e6ad2 (MD5) / Made available in DSpace on 2018-04-17T17:00:16Z (GMT). No. of bitstreams: 1 43- Thamyris da Silva Evangelista - DESENVOLVIMENTO DE SUPERF?CIE SELETIVA EM FREQU?NCIA RECONFIGUR?VEL BASEADA NA GEOMETRIA ESTRELA DE QUATRO BRA?OS PARA APLICA??O EM 2,4 GHz.pdf: 3077852 bytes, checksum: e604c3a3df9471f48941fe95027e6ad2 (MD5) Previous issue date: 2018-03-26 / IFPB / Diante da atual demanda dos sistemas de telecomunica??es, as superf?cies seletivas em frequ?ncia, FSS ativas e passivas, v?m atraindo a aten??o de diversos grupos de pesquisa por suas in?meras aplica??es, tais como: refletores de antena, janelas eficientes, paredes inteligentes, entre outras. Neste cen?rio, neste trabalho ? apresentado o desenvolvimento de uma superf?cie seletiva em frequ?ncia reconfigur?vel baseada na geometria estrela de quatro bra?os para aplica??o na faixa de 2400-2483,5 MHz dos padr?es IEEE 802.11b/g/n (Wi-Fi) e IEEE 802.15 (Bluetooth). Como elemento de comuta??o foi utilizado o diodo PIN. S?o apresentados resultados num?ricos, obtidos utilizando o software comercial ANSYS Designer que se baseia no M?todo dos Momentos, MoM, e resultados experimentais, observando-se uma boa concord?ncia entre os mesmos. No estado ligado (ON), a partir da aplica??o de uma tens?o de V = 1,8 V, a FSS rejeita a faixa de frequ?ncia de 2,4 GHz. Para o estado desligado, (OFF) a FSS deixa de atenuar esta faixa de frequ?ncia. Tamb?m foram realizadas medi??es da intensidade do sinal de Wi-Fi com o aux?lio do software Homedale e os resultados obtidos foram bastante satisfat?rios, confirmando a efici?ncia da geometria proposta.

Real-time voice measurements were performed to assess whether there are significant problems with 802.11b wireless networks regarding real-time voice communication. We present an analysis of how the 802.11b MAC protocol and diverse environmental conditions affect the quality of real-time voice in terms of loss, delay, and jitter. We also reveal practical issues of wireless monitoring with passive sniffers for this type of analysis. The results obtained in our measurements show that in the majority of the experiments the quality was good, but under some circumstances the requirements for an acceptable voice communication were not met. / Realtidsröstmätningar gjordes för att testa om det finns problem med 802.11b trådlösa nätverk beträffande realtidsröstkommunikation. En analys presenteras av hur 802.11b MACs protokoll och olika tillstånd i omgivningen påverkar kvaliteten på realtidsrösten i form av förluster, fördröjningar och jitter. Även praktiska angelägenheter om trådlös övervakning med passiva sniffers visas. De erhållna resultaten visar att i en majoritet av fallen var kvaliteten acceptabel, men under vissa förhållanden blev inte kraven för röstkommunikation uppfyllda.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: In recent years the demand for bandwidth has dramatically increased because of new applications for data and multimedia, and wireless technology has prevailed as a prominent technology for data connectivity, especially for home, office and last mile services. As wireless communications are dependant upon spectrum availability, which is communal, this scarce commodity in communication has to be used as efficiently as possible. Some aspects of this requirement are addressed in this project. We chose the IEEE 802.11b standard for this particular investigation because of its widespread use, the vast amount of applicable literature, the variety of software simulation tools and the ease with which equipment can be obtained. The IEEE 802.11 standard specified the Point Coordination Function as the de- terministic protocol. Recently research into this aspect has stagnated, and it was the purpose of this project to investigate how existing infrastructure networks could be improved by optimising some modes of the 802.11 protocol. The investigation also hoped to determine when to change between Distributed Coordination Function (DCF) and Point Coordination Function (PCF), and to provide an adaptive protocol to do so. This thesis presents mathematical models for the operation of DCF and PCF modes, which is compared with results from a network simulator (ns2), for theoretical veri- fication. A protocol is also proposed to dynamically switch between DCF and PCF, to harness the advantages they present. / AFRIKAANSE OPSOMMING: Die afgelope paar jaar het die aanvraag na bandwydte dramaties verhoog as gevolg van nuwe toepassings vir data en multimedia, en draadlose tegnologie het voorgekom as ’n dominante tegnologie vir data konnektiwiteit, veral vir die huis, kantoor en laaste myl dienste. Omdat draadlose kommunikasie afhanklik is van spektrum beskikbaarheid, wat gemeenskaplik is, moet hierdie skaars kommoditeit in kommunikasie so effektief moontlik gebruik word. Sekere aspekte van die vereiste sal in die tesis ondersoek word. Dit is besluit om die IEEE 802.11b standard vir die spesifieke ondersoek te gebruik as gevolg van die wye toepassing, die groot hoeveelheid beskikbare literatuur, die verskeidenheid simulasie sagteware en die gemak waarmee die toerusting bekom kan word. Die IEEE 802.11 standaard spesifiseer the Punt Koordinasie Funksie (PCF) as die deterministiese protokol vir die betrokke standaard. Onlangs het navorsing oor hierdie aspek gestagneer, en dit is die doel van die projek om te ondersoek hoe bestaande infrastruktuur netwerke moontlik verbeter kan word deur optimering van sekere modusse van die 802.11 protokol. Die ondersoek hoop ook om te bepaal wanneer die oorgang van die Distrubusie Koordinasie Funksie (DCF) en Punt Ko- ordinasie Funksie sal plaasvind, en om ’n dienooreenstemmende protokol te on- twikkel. Die tesis verskaf wiskundige modelle vir die werking van die DCF en PCF modusse, wat vergelyk word met resultate uit ’n netwerk simulator (ns2), vir teoretiese ver- ifikasie. ’n Protokol word ook voorgestel om dinamies te wissel tussen DCF and PCF, om die voordele wat die protokolle verskaf te gebruik.

This work deals with roaming issues in the WiFi network. Takes options from a 802.11 standard view. Factory setting options for fast roaming from CISCO and MikroTik. It proposes to measure and test these networks.

This thesis is concerned the technology with technologies of transfer through wireless devices. It is about possibilities of optimization of transfer in wireless net, especially of the reduction of interference influence. The first part is about theory and the standards development of wireless technology. There are methods and principles used in wireless technologies. The second part is a practical measuring and testing of an internal wireless net, with the emphasis being on the source of interference influence. Measuring was focused on interference between access points and was not about meteorological influence. It continues with theory and testing of interference of the microwave oven in our wireless net. Then, it is a practical demonstration of interference in an external environment. There are practical examples of interference between different providers’ nets on the same area and solutions to prevent or to cancel this interference. In next part of work the wireless net is parsed and described in a given territory. Here is described the way how to precede the reciprocal interference and eventually how this mutual disturbance suppress. Consequently, our net is optimized for customer growth and for today’s options of newer and more powerful components for wireless transfer. Finally there are two laboratory tasks. The first one is about practical measuring and testing of wireless net’s parameters and the second one is about simulation of wireless networks in the Opnet program.

This work deals with the wireless Wi-Fi networks, that used unlicenced ISM frequency band 2,4 GHz. These wireless networks are very extended in these days and used mainly for the Internet connection. With the multimedia data transfers expanding it’s necessary to ensure the specific quality of service QoS in wireless networks mainly for applications, which are sensitive to delay or packets lost. The main aim of this work is to describe Wi-Fi networks based on IEEE 802.11b/g/n standards, description of QoS techniques according to IEEE 802.11e standard and description of parameters describing QoS for the VoIP services. The practical part is divided on a two parts. The problems of measuring the radio link quality and the creation of simple program for quality of wireless connection analysis are solved in the first part. The second part incluledes measuring of the lost packets number in Wi-Fi network with the commercial application AirMagnet Laptop Wireless LAN Analyzer and measuring of the signal noise influence with the help of spectrum analyzer and vector signal generator.

The recent growth in the ambit of modern wireless communication and in particular WLAN (Wireless Local Area Network) systems has created a niche for novel designs that have the capacity to send and/or receive arbitrary orthogonal polarizations. The designs should also be able to support dual-band functionality, while maintaining a compact structure. The first aim of this dissertation was thus to develop a dual-band single radiating element that can cover the 2.4 GHz (2.4 – 2.484 GHz) band and the 5.2 GHz (5.15 – 5.85 GHz) band for the IEEE 802.11b and IEEE 802.11a WLAN standards respectively. Dual-frequency elements such as stacked-, notched- and dichroic patches have been considered, but due to the size and the high cross-polarization levels associated with these designs, the design process was propelled towards various dipole and monopole configurations. The attributes of various designs were compared, where the double Rhombus antenna pregnant with dual-band and dual-polarization potential was used as basis in the development of the DBDP (Dual-Band Dual-Polarized) antenna design. The single-element design exhibited wide bandwidths, good end-fire radiation patterns and relatively high gain over the 2.4/5.2 GHz bands. A two-element configuration was also designed and tested, to firstly increase the gain of the configuration and secondly to facilitate the transformation of the dipole design into a dual-polarized configuration. The second aim of this dissertation was to develop a dual-polarized array, while making use of only two ports, each pertaining to a specific polarization and to implement the design on a single-dielectric-layer substrate. Most dual-polarized structures such as circular, square and annular microstrip antenna designs only support one band, where multi-dielectric-layer structures are the norm. The disadvantages associated with multi-layered designs, such as fabrication difficulties, high costs, high back lobes and the size of the arrays, further supported the notion of developing an alternative configuration. The second contribution was thus the orthogonal interleaving of the two-element array configurations, to address the paucity of single-dielectric-layer dual-band dual-polarized designs that can be implemented with only two ports. This design was first developed and simulated with the aid of the commercial software package CST Microwave Studio® and the results were later corroborated with the measured data obtained from the Compact Antenna Range at the University of Pretoria. AFRIKAANS : Die onlangse groei in die area van moderne draadlose kommunikasie en met spesifieke verwysing na DLAN (Draadlose Lokale Area Netwerk) stelsels, het ‘n nis vir nuwe ontwerpe geskep. Daar word van hierdie nuwe ontwerpe die kapasiteit verlang om verskeie ortogonale polarisasies te stuur en/of te ontvang in samewerking met dubbel-band eienskappe, terwyl ‘n kompakte struktuur nogsteeds aandag moet geniet. Die eerste doel met hierdie verhandeling was dus die ontwikkeling van ‘n dubbel-band enkel stralingselement wat instaat is om die 2.4 GHz (2.4 – 2.484 GHz) band en die 5.2 GHz (5.15 – 5.85 GHz) band wat as die IEEE 802.11b en die IEEE 802.11a DLAN standaarde respektiewelik bekend staan, te bedek. Dubbel-frekwensie elemente soos onder andere die gepakte-, merkkepie- en dichromatiese strook antenne was as moontlike oplossings ondersoek, maar die grootte en hoë kruispolarisasie wat gewoonlik met hierdie ontwerpe gepaard gaan, het die ontwerpsproses in die rigting van verskeie dipool en monopool konfigurasies gestoot. Die aantreklike eienskappe van die verskeie ontwerpe was met mekaar vergelyk, waar die dubbel Rhombus antenna, verwagtend met dubbel-band dubbel-polarisasie potensiaal, as basis vir die ontwikkeling van die DBDP (Dubbel-Band Dubbel-Polarisasie) antenna ontwerp gebruik is. Die enkelelementontwerp het wye bandwydtes, goeie direktiewe stralingspatrone en relatiewe hoë wins oor die 2.4/5.2 GHz bande geopenbaar. Die twee-element konfigurasies was ook ontwerp en getoets om eerstens die wins van die konfigurasie te verhoog en tweedens om die transformasie na ‘n dubbel-gepolariseerde konfigurasie te fassiliteer. Die tweede doel van hierdie verhandeling was om ‘n dubbel-gepolariseerde elementopstelling met net twee poorte te ontwikkel, waar elkeen verantwoordelik is vir ‘n spesifieke polarisasie, en te implementeer op ‘n enkel-diëlektriese-laag substraat. Die meeste dubble-polarisasiestrukture, soos onder andere die sirkulêre-, vierkantige- en ringvormige antenne ontwerpe, kan net een frekwensieband onderhou en word gewoonlik met behulp van meervoudige-diëlektriese-laagstrukture geimplementeer. Die negatiewe eienskappe soos onder andere die vervaardigingsmoeilikhede, hoë kostes, hoë teruglobbe en die grootte van die meervoudige-elementopstellings wat aan hierdie meervoudige-diëlektriese-laagontwerpe behoort, het verder die denkbeeld van ‘n alternatiewe konfigurasie bekragtig. Die tweede hoofbydrae was dus die ortogonale insleuteling van die twee-element meervoudige-elementopstelling konfigurasies om die geringheid van enkel-diëlektriese-laag dubbel-band dubbel-polarisasie ontwerpe, wat net met twee poorte geïmplementeer kan word, te adresseer. Hierdie ontwerp was eers met behulp van die kommersiële sagtewarepakket CST Microwave Studio® ontwikkel en gesimuleer, waarna die resultate bevestig was deur meetings by die Kompakte Antenna Meetbaan van die Universiteit van Pretoria. / Dissertation (MEng)--University of Pretoria, 2011. / Electrical, Electronic and Computer Engineering / unrestricted