Design and Optimization of Tunable Matching Networks and Aperture-Tuned Antennas for Mobile Wireless Devices

In the current wireless market, users have a high level of expectations regarding the functionalities and services added to their wireless mobile devices. At the same time, they also expect performance to remain optimal. In order to meet users’ heightened expectations, the level of integration between different subsystems of wireless radios must increase exponentially to keep pace with the increased demand of functionalities. For example, the current size limitations for mobile wireless devices allow space for only a single antenna, but this antenna must cover dual frequency bands, the first extending from 800MHz to 960MHz and the second from 1710MHz to 2300MHz. Extending the antenna bandwidth to cover the lower edge of the spectrum without increasing the physical size of the antenna is a challenging task. Meanwhile, there is also a demand to decrease antenna size to achieve more compact wireless mobile devices and to free up space for newly added features. One means to achieve these contradicting requirements is to use impedance tuners to enable a small-sized antenna to cover wider range of frequencies. In this thesis, we investigate some methods of applying impedance tuners. First, we conduct a comprehensive study on the tuning range of multiple network topologies, after which we present a design method to substitute impractical and expensive variable inductors with practical and relatively inexpensive fixed inductors connected to variable capacitors. These serve as building blocks for impedance tuners. This is followed by a performance investigation of a readily available tunable capacitor. The equivalent circuit is extracted at different bias voltages and across the frequency range of interest. This circuit model is used in the fourth part of this thesis as an input to the simulator. Next, we conduct multiple simulation runs to demonstrate the major differences between two methods of impedance tuning: a tunable matching network and an aperture-based antenna tuning. The simulation results demonstrate the performance limitations of each technique. Finally, we verify the study findings by measurements in an anechoic RF chamber, discovering that the conducted measurements conform to the obtained simulation results

The chromosomal DNA damage in buccal mucosa cells among schools children in the vicinity of mobile base stations in Selangor

Introduction: The increased use of mobile phones has increased the mobile base stations (MBS) deployment. While understanding of radiation protection is growing among the public, questions regarding early-life exposure to radiofrequency radiation (RFR) from MBS in children are of importance as to whether it will raise the chances of developing chronic diseases during adulthood. Taking into account the sitting location of MBS, the purpose of this study is to evaluate the chromosomal DNA damage in buccal mucosal cells between school children exposed to RFR emitted from base station antennas. Method: This is a comparative cross-sectional study in which two group of school children were sampled i.e. exposed groups are children whose school located near MBS (≤200 meters); unexposed groups are children whose school located distant far from the MBS (>200 meters). Digital RF Analyzer was used to measure RFR at the school surrounding. Buccal mucosa cells from the oral cavity were sampled to examine the level of micronuclei (MN) frequencies. Results: This study found that the densities of the RFR energy differed in range. Although all measurements showed the RFR reading below the acceptable exposure level, there were still significant variations at each location assessed. Statistically, the MN frequency is significantly different when compared to the exposed and non-exposed group. Conclusion: To understand the mechanism of health effects from exposure to low-level RFR emited from MBS, further study should consider environmental factors influencing MBS sitting on RFR emission, as well as examining the health effects into molecular levels

Comparative international analysis of radiofrequency exposure surveys of mobile communication radio base stations

This paper presents analyses of data from surveys of radio base stations in 23 countries across five continents from the year 2000 onward and includes over 173,000 individual data points. The research compared the results of the national surveys, investigated chronological trends and compared exposures by technology. The key findings from this data are that irrespective of country, the year and cellular technology, exposures to radio signals at ground level were only a small fraction of the relevant human exposure standards. Importantly, there has been no significant increase in exposure levels since the widespread introduction of 3G mobile services, which should be reassuring for policy makers and negate the need for post-installation measurements at ground level for compliance purposes. There may be areas close to antennas where compliance levels could be exceeded. Future potential work includes extending the study to additional countries, development of cumulative exposure distributions and investigating the possibility of linking exposure measurements to population statistics to assess the distribution of exposure levels relative to population percentiles

REAL TIME DATA ACQUISITION AND MONITORING OF PATIENTS WITH CORONARY HEART DISEASE IN A HOME ENVIRONMENT

The high mortality rate associated with cardiovascular related diseases requires the implementation of a personalised, ubiquitous health monitoring system. With the recent advancements of wireless sensor network technologies, these study proposes a real time data acquisition and monitoring system for patients with a track history of coronary heart diseases based on the implementation of a microcontroller, GSM Module and temperature sensors. This pervasive healthcare system will provide a round the clock monitoring and has an in built alerting mechanism for detecting anomalies in cardiac activities. The aim of the study is to minimize the need for caretakers and help the gravely ill senior citizens to survive an independent life. Apart from that, this study will help reduce the mortality rate of victim by shortening the response time of medical team to the victims. In these study, the proposed design mechanism will consider the following key criteria namely safety, data security, energy efficiency, durability and cost incurred

Broadband design on dual and circularly polarized antennas for wireless communication systems

Master'sMASTER OF ENGINEERIN

Soft handover issues in radio resource management for 3G WCDMA networks

PhDMobile terminals allow users to access services while on the move. This unique feature has driven the rapid growth in the mobile network industry, changing it from a new technology into a massive industry within less than two decades. Handover is the essential functionality for dealing with the mobility of the mobile users. Compared with the conventional hard handover employed in the GSM mobile networks, the soft handover used in IS-95 and being proposed for 3G has better performance on both link and system level. Previous work on soft handover has led to several algorithms being proposed and extensive research has been conducted on the performance analysis and parameters optimisation of these algorithms. Most of the previous analysis focused on the uplink direction. However, in future mobile networks, the downlink is more likely to be the bottleneck of the system capacity because of the asymmetric nature of new services, such as Internet traffic. In this thesis, an in-depth study of the soft handover effects on the downlink direction of WCDMA networks is carried out, leading to a new method of optimising soft handover for maximising the downlink capacity and a new power control approach

Radiosignaalin vaimennusmittauksia nykyaikaisissa asuintaloissa. Loppuraportti

Tässä teknisessä raportissa käsitellään radiotaajuussignaalien etenemisvaimennuksia nykyaikaisissa asuintaloissa. Raportissa esitettävien mittatulosten perusteella nykyaikainen rakentaminen vaimentaa radiotaajuussignaaleja enemmän kuin vanhoihin standardeihin perustunut rakentaminen. Rakennusten energiankulutuksen hillitseminen on tällä hetkellä varsikin Suomessa merkittävässä yhteiskunnallisessa roolissa johtuen siihen käytettävän kokonaisenergian merkittävästä osuudesta. Energiankulutuksen hillitsemistä ohjaavat myös ilmastonmuutoksen aiheuttamat paineet ja alati kasvava pelko energian loppumisesta. Kasvavien energiatehokkuusvaateiden vuoksi rakennusten eristyskykyä on pyritty ja pyritään edelleen kasvattamaan myös tulevaisuudessa. Nämä tekijät ovat vieneet asuintalojen kehitystä kohti energiatehokkaampia ratkaisuja, jotka perustuvat pitkälti metallikerroksien sekä erilaisten metalliseoksien käyttöön. Tämä on kuitenkin langattomassa viestinnässä käytettävien radiotaajuisten signaalien kannalta ongelmallista, koska ne eivät pysty läpäisemään metallikerrosta hyvin. Tämän seurauksena langattomien palvelujen saatavuus heikkenee erittäin tiiviisti rakennetuissa asuintaloissa. Ongelmat korostuvat entuudestaan mikäli rakentamisessa on käytetty jotain metallipohjaisia rakennusmateriaaleja. Raportissa esitettyjen mittaustulosten perusteella uusien rakennusmateriaalien kuten energiatehokkaiden ikkunoiden (selektiivilasit) ja alumiinipohjaisten polyuretaanilevyjen vaimennukset materiaaleina ovat merkittäviä, varsinkin yleisesti käytettävillä matkaviestintaajuuksilla (900MHz, 2100 MHz). Esimerkiksi 2100 MHz taajuudella eristelevyjen sekä ikkunoiden RF-vaimennukset voivat olla jopa 40 dB. Toisien sanoen, signaalitaso vaimenee 10 000 osaan alkuperäisestä. Asuintaloissa taloissa tehtyjen mittausten perusteella havaittiin noin 10 - 20 dB (eli 10 - 100 -kertaisesti) enemmän vaimennusta 2100 MHz taajuuksilla verrattuna vanhojen standardien perusteella rakennettuun tiilivuorattuun pientaloon. Näiden lisävaimennusten myötä operaattorit joutuvatkin vaikeuksiin asiakkaidensa kanssa kuuluvuusongelmien vuoksi. Langattomien järjestelmien tukiasemaverkosto tulee tulevaisuudessa kasvavaan ja osittain parantamaan kuuluvuutta vaikka rakennusten RF-vaimennukset kasvatkin. Esimerkiksi käsillä olevan mobiilidatan räjähdysmäinen kasvu ajaa operaattoreita keskittymään erityisratkaisuihin kuuluvuuden ja verkon kapasiteetin suhteen. Käytännössä tämä tarkoittaa erilaisen kotitukiasemien ja sisäverkkoratkaisujen lukumääräistä kasvua. Tämä ei valitettavasti yksin riitä ratkaisemaan ongelmaa, varsinkaan yleiskuuluvuuden osalta. Yhtenä keskeisenä ratkaisuna nähdäänkin rakenteisiin tehtävät muutokset; joko rakennusmateriaalien valmistusvaiheessa tai sitten jälkiasennuksena. Tämä puolestaan vaatii muutoksia rakennussäädöksiin ja lainsäädäntöön, jota kautta pystyttäisiin vaikuttamaan rakennuselementtien valmistusprosesseihin.publishedVersio

REAL TIME DATA ACQUISITION AND MONITORING OF PATIENTS WITH CORONARY HEART DISEASE IN A HOME ENVIRONMENT

The high mortality rate associated with cardiovascular related diseases requires the implementation of a personalised, ubiquitous health monitoring system. With the recent advancements of wireless sensor network technologies, these study proposes a real time data acquisition and monitoring system for patients with a track history of coronary heart diseases based on the implementation of a microcontroller, GSM Module and temperature sensors. This pervasive healthcare system will provide a round the clock monitoring and has an in built alerting mechanism for detecting anomalies in cardiac activities. The aim of the study is to minimize the need for caretakers and help the gravely ill senior citizens to survive an independent life. Apart from that, this study will help reduce the mortality rate of victim by shortening the response time of medical team to the victims. In these study, the proposed design mechanism will consider the following key criteria namely safety, data security, energy efficiency, durability and cost incurred

Radio network planning and optimisation for WCDMA

The present thesis introduces the radio network planning process and optimisation for WCDMA (FDD mode), as defined by 3GPP. This thesis consists of three parts: modelling and tools for radio network planning, process for pre-operational network control and optimisation for the operational network. General challenges to face in 3G network control are based on the fact that many issues are interconnected and should be simultaneously considered, such as Planning means not only to meet current status and demands, but the solution should also comply with the future requirements by providing an acceptable development path. Traffic modelling is not only the question about the total amount of traffic growth, but also the question about the future service distribution and performance demands. All CDMA systems have a relation between capacity and coverage. Consequently, the network planning itself is not only based on propagation estimation but also on the interference situation in the network. Ideally, site selection consideration will be done based on the network analysis with planned load and traffic/service portfolio, taking possible co-siting constraints into account. Provision of multiple services and seamless management of at least two multiple access systems require rapid evolution of the management tools and processes. The network performance in terms of capacity, quality, and implementation and operational costs forms a multidimensional space. Operators' task will be to convert the business strategy to an operating point in the performance space in a cost efficient manner. The contribution of this thesis in terms of modelling and tools is as follows: Improvement of the accuracy of radio link budget by introducing power control headroom (also called fast fading margin). Improvement of loading equation by introducing a transmit power increase term. Development of theory and modelling for a planning tool capable of multi-service and multi-carrier interference, capacity and coverage analysis. Development and implementation an interface taking into account the true traffic distribution (not uniform) and terminal speed. In the area of pre-operational planning process the contribution of this thesis is as follows: Development of dimensioning methodology for multi-service network site density estimation, utilising the modelling of power control headroom, transmit power increase, soft handover and Eb/N0. Development of radio network planning process for multi-service environment including capacity and coverage evaluation for a given traffic mixture, quality and area requirements. Analysis of means to improve radio network performance with Mast Head Amplifier (MHA), diversity reception, sectorisation and proper antenna selection. In the area of optimisation of the operational network the contribution of this thesis is as follows: Definition for optimisation target in the case of 3G. The optimisation will be capacity-quality trade-off management instead of plain quality improvement process. Introduction of Self Organizing Map (SOM) in the analysis of cellular networks. Analysis of the applicability of SOM in WCDMA cellular network optimisation. Introduction of SOM based applications to support network capacity-quality trade-off management. It is worth noting that process and methods described in this work are not limited to 3G systems with WCDMA radio access technology, but they are applicable to other CDMA standards as well.reviewe