Mobile-phone antenna design

published_or_final_versio

Mobile-phone antenna design

published_or_final_versio

Navigation/traffic control satellite mission study. Volume 3 - System concepts

Satellite network for air traffic control, solar flare warning, and collision avoidanc

AgRISTARS. Supporting research: MARS x-band scatterometer

The design, construction, and data collection procedures of the mobile agricultural radar sensor (MARS) x band scatterometer are described. This system is an inexpensive, highly mobile, truck mounted FM-CW radar operating at a center frequency of 10.2 GHz. The antennas, which allow for VV and VH polarizations, are configured in a side looking mode that allows for drive by data collection. This configuration shortens fieldwork time considerably while increasing statistical confidence in the data. Both internal calibration, via a delay line, and external calibration with a Luneberg lens are used to calibrate the instrument in terms of sigma(o). The radar scattering cross section per unit area, sigma(o), is found using the radar equation

Comparison of EMP and HERO programs

Because of the unique features of electromagnetic pulse (EMP) and Hazardous Electromagnetic Effects on Ordnance (HERO), much research and money has gone into protecting weapon systems and ordnance against it. The EMP and HERO phenomena do have a variety of differences and require differences of hardening technique to protect against it. However, they both involve radiation effects and can prematurely initiate ordnance via the electroexplosive device (EED). Protection of weapon systems and ordnance against electronic damage and upset plus EED initiation takes on more of an art form rather than science once basic principles are applied. Nevertheless by relating these two programs via the initiating temperature of the EED. they can be accurately compared with each other. Because of this observation, the two programs can be effectively combined to work jointly on ordnance hardening and protection including all forms of radiation type hazards, present and future.http://archive.org/details/comparisonofemph00bogaLieutenant. United States NavyApproved for public release; distribution is unlimited

Miniaturization and evaluation methods of mobile terminal antenna structures

In recent years, the trend in the mobile communications market has been towards thinner and mechanically more complex terminal devices, which are able to operate in several wireless systems. Due to this development, miniaturization and performance enhancement of internal mobile terminal antennas have become major challenges for the industry of the field. Not only should an internal antenna be small in size and broadband, it must also be able to ensure reliable power transmission in a real multipath propagation environment. A well-known way to improve the reliability of a radio connection is to use multi-antenna reception in the mobile terminal. In multiple-input multiple-output (MIMO) systems, multiple antennas are additionally used at the base station. In both cases, fast and reliable methods are needed for the performance evaluation of multi-antenna terminals. In the first part of this thesis, the main benefits, drawbacks and applications of coupling element based mobile terminal antenna structures are studied, with special emphasis on antenna miniaturization. Optimum shaping and placement of capacitive coupling elements are first studied in this work. Next, it is demonstrated by simulations and measurements that the bandwidth-to-volume ratio of a mobile terminal antenna structure can be improved significantly by using optimized coupling elements instead of traditional self-resonant antenna elements. To facilitate the implementation of coupling element based multi-resonant antenna structures, a theoretical study on the dual-resonant impedance matching of non-resonant coupling elements is also presented. The feasibility of coupling elements for multi-band terminals is demonstrated with a novel quad-band GSM antenna, which consumes a total volume of only 0.7 cm3. Finally, a novel frequency tunable matching circuitry designed for non-resonant coupling elements is introduced. In this work, also the bandwidth, efficiency in talk position, and SAR (specific absorption rate) of mobile phone antennas are studied as a function of frequency over wide frequency band (0.6 GHz - 6 GHz) by applying the idea of coupling elements. The results show that below 3 GHz the three parameters are strongly affected by the resonant wavemodes of the chassis, whereas above 3 GHz, the wavemodes of the coupling element dominate. In addition to the above, the resonant wavemodes of the chassis of a clamshell phone are investigated in this work by using coupling elements. The results bring out several challenges, such as a non-radiating resonance, that an antenna designer may face with clamshell phones. The second part of this thesis concentrates on the performance evaluation of mobile terminal multi-antenna configurations. First, the accuracy of a novel measurement based antenna test bed (MEBAT) is thoroughly studied. After this, the performance of several mobile terminal multi-antenna configurations is systematically investigated using the MEBAT. The emphasis is kept on the power reception properties (effective array gain or EAG) of the multi-antenna configurations. An accurate and fast theoretical way of predicting the median EAG of an antenna configuration is proposed in the work. Based on a comprehensive analysis of the theoretical and empirical EAG results, guidelines for optimum radiation pattern characteristics of a multi-antenna configuration are given. Based on the eigenvalue dispersion and capacity results obtained in the studied MIMO environments, it is concluded that it may be difficult to affect the spatial multiplexing properties of a MIMO system by means of handset antenna design. The presented results indicate that a handset antenna designer should mainly focus on maximizing the EAG.Viime vuosina yleinen kehityssuunta matkaviestinmarkkinoilla on ollut kohti ohuempia ja mekaanisesti monimutkaisempia päätelaitteita, jotka kykenevät toimimaan useissa langattomissa järjestelmissä. Tämän kehityksen johdosta matkapuhelinten sisäisten antennien koon pienentäminen ja suorituskyvyn parantaminen ovat muodostuneet merkittäviksi haasteiksi alan teollisuudelle. Sen lisäksi, että sisäisen antennin tulee olla pienikokoinen ja laajakaistainen, tulee sen myös kyetä takaamaan luotettava tehonsiirto todellisessa monitie-etenemisympäristössä. Hyvin tunnettu tapa radioyhteyden luotettavuuden parantamiseksi on hyödyntää moniantennivastaanottoa matkapuhelimessa. Multiple-input multiple-output (MIMO)-järjestelmissä useita antenneja hyödynnetään lisäksi tukiasemassa. Kummassakin tapauksessa tarvitaan nopeita ja luotettavia menetelmiä matkapuhelinten moniantennirakenteiden suorituskyvyn arvioimiseksi. Työn ensimmäisessä osassa tutkitaan kytkentäelementteihin perustuvien antennirakenteiden tärkeimpiä hyötyjä, haittoja ja sovelluksia painottaen antennien koon pienentämistä. Työssä tutkitaan ensin kapasitiivisten kytkentäelementtien optimaalista muotoilua ja sijoittamista. Seuraavaksi osoitetaan simulaatioin ja mittauksin, että matkapuhelimen antennirakenteen kaistanleveys-tilavuus-suhdetta saadaan parannettua huomattavasti käyttämällä optimoituja kytkentäelementtejä perinteisten resonanssityyppisten antennielementtien sijaan. Kytkentäelementteihin perustuvien moniresonanssi antennirakenteiden toteuttamisen helpottamiseksi työssä esitetään myös teoreettinen tutkimus ei-resonoivien kytkentäelementtien sovittamisesta kaksoisresonanssiin. Kytkentäelementtien soveltuvuutta monitaajuuspäätelaitteisiin havainnollistetaan uudentyyppisellä nelitaajuus-GSM-antennilla, jonka kokonaistilavuus on ainoastaan 0.7 cm3. Lopuksi esitellään uudentyyppinen kytkentäelementeille suunniteltu taajuussäädettävä sovituspiiri. Tässä työssä tutkitaan myös matkapuhelinantennien kaistanleveyttä, hyötysuhdetta puheasennossa ja SAR- (specific absorption rate) arvoja taajuuden funktiona laajalla taajuuskaistalla (0.6 GHz - 6 GHz) hyödyntäen kytkentäelementtejä. Tulokset osoittavat, että 3 GHz:n alapuolella näihin kolmeen parametriin vaikuttavat vahvasti rungon resonoivat aaltomuodot, kun taas 3 GHz:n yläpuolella kytkentäelementin aaltomuodot dominoivat. Yllä olevan lisäksi työssä tutkitaan taitettavan puhelimen rungon resonoivia aaltomuotoja kytkentäelementtien avulla. Tulokset tuovat esille useita haasteita, kuten säteilemättömän resonanssin, joita antennisuunnittelija saattaa kohdata taitettavien puhelinten kanssa. Työn toinen osa keskittyy matkapuhelinten moniantennirakenteiden suorituskyvyn arviointiin. Ensin uudentyyppisen mittauksiin perustuvan antennien testialustan (MEBAT) tarkkuutta arvioidaan perusteellisesti. Tämän jälkeen useiden matkapuhelinten moniantennirakenteiden suorituskykyä tutkitaan järjestelmällisesti MEBATin avulla. Painotus on moniantennirakenteiden tehovastaanotto-ominaisuuksissa (effective array gain tai EAG). Työssä ehdotetaan tarkkaa ja nopeaa teoreettista tapaa antennirakenteen EAG:n mediaanin ennustamiseksi. Teoreettisten ja empiiristen EAG-tulosten perusteellisen analyysin pohjalta annetaan suosituksia moniantennijärjestelmän säteilykuvion optimaalisille ominaisuuksille. Tutkituissa MIMO-järjestelmissä saatujen ominaisarvohaje- ja kapasiteettitulosten perusteella tehdään johtopäätös, että matkapuhelimen antennisuunnittelun keinoin voi olla vaikeaa vaikuttaa MIMO-järjestelmän kykyyn muodostaa rinnakkaisia kanavia. Esitetyt tulokset ehdottavat, että matkapuhelimen antennisuunnittelijan tulisi pääasiassa keskittyä EAG:n maksimointiin.reviewe

NASA Tech Briefs, July 1996

Topics covered include: Mechanical Components; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Mathematics and Information Sciences; Life Sciences; Books and Report

High Frequency Multiferroic Devices

This dissertation focuses on high frequency multiferroic devices from both theoretical and experimental aspects. Some potential applications for high frequency multiferroic: antennas, logic and memory, will be presented in this dissertation. The introduction section provides a fundamental explanation on the multiferroic devices as well as the modeling methods for strain-mediated multiferroic systems. Former researches indicate that the composites of piezoelectric substrate and the magnetoelastic material show great potential on reducing both the devices’ size as well as energy consumption.Part I of the dissertation shows multiferroics for antenna applications. Conventionally, antennas such as dipoles and loops rely on an electromagnetic (EM) wave resonance. Therefore, the sizes of such antennas are within the same order of free space wavelength. Multiferroic antenna can transfer the EM wave into an acoustic wave, which has much smaller wavelength compared with the wavelength of the EM wave under the same frequency. In this way, multiferroic antennas show a promising path for reducing the antenna system’s size, weight and volume. Also, three multiferroic antennas: shear wave antenna, lamb wave antenna as well as tunable frequency broadband antenna are introduced in this section. The shear wave antenna and lamb wave antenna are studied experimentally, and the tunable frequency broadband antenna is studied theoretically. All of them show great potential on reducing the antenna’s size.Part II of this dissertation indicates other applications of multiferroic devices: logic and memory. For the logic aspects, a numerical simulation is performed on in-plane mode Bennett clocking systems. For memory aspects, a new concept for breaking the switch symmetry the high frequency control of the magnetization in nanodisk. In this part, a fully coupled finite element model is used to simulate the switch process of the magnetization in the nanodisks. This voltage-controlled process has potential be used in magnetic memory devices with very low energy dissipations

Wireless Electromagnetic Radiation Assessment Based on the Specific Absorption Rate (SAR): A Review Case Study

Employing Electromagnetic Fields (EMFs) in new wireless communication and sensing technologies has substantially increased the level of human exposure to EMF waves. This paper presents a useful insight into the interaction of electromagnetic fields with biological media that is defined by the heat generation due to induced currents and dielectric loss. The Specific Absorption Rate (SAR) defines the heating amount in a biological medium that is irradiated by an electromagnetic field value. The paper reviews the radio frequency hazards due to the SAR based on various safety standards and organisations, including a detailed investigation of previously published work in terms of modelling and measurements. It also summarizes the most common techniques utilised between 1978 and 2021, in terms of the operational frequency spectrum, bandwidth, and SAR values

Interaction of antenna systems with human body

The research investigates the influence on the human body on a communication system. To understand this, the effect of hands free kit (HFK) on energy absorption in the body was investigated when operating a smart phone at 2G. Findings on the research are given in the thesis report. Also, the influence of the way in which a phone is held on a phone s received power was investigated. The result was compared to that obtained using a hand phantom acquired from SPEAG. This was to check if the hand phantom best represents the human hand when using it in experiments. The setup for the experiment was in an anechoic chamber at Loughborough University. The mobile phone transmitted in the 2G system. In further experiments carried out on the body, two antennas were attached to the body in six different orientations to receive power from a source creating a Single Input Multiple Output (SIMO) system. The antennas used were monopoles mounted on a circular ground plane. These antennas were designed and constructed with the influence of the body taken into consideration. The use of diversity techniques to improve transmission to an on-body system is investigated with the antennas on the body. For each alignment, the transmission to the on-body was compared with the transmission to the corresponding off-body (free space). Experiments for this work were carried out in three environments