Concentrated Ground Plane Booster Antenna Technology for Multiband Operation in Handset Devices

The current demand in the handset antenna field requires multiband antennas due to the existence of multiple communication standards and the emergence of new ones. At the same time, antennas with reduced dimensions are strongly required in order to be easily integrated. In this sense, the paper proposes a compact radiating system that uses two non-resonant elements to properly excite the ground plane to solve the abovementioned shortcomings by minimizing the required Printed Circuit Board (PCB) area while ensuring a multiband performance. These non-resonant elements are called here ground plane boosters since they excite an efficient mode of the ground plane. The proposed radiating system comprises two ground plane boosters of small dimensions of 5 mm x 5 mm x 5 mm. One is in charge of the low frequency region (0.824-0.960 GHz) and the other is in charge of the high frequency region (1.710-2.170 GHz). With the aim of achieving a compact configuration, the two boosters are placed close to each other in a corner of the ground plane of a handset device (concentrated architecture). Several experiments related to the coupling between boosters have been carried out in two different platforms (barphone and smartphone), and the best position and the required matching network are presented. The novel proposal achieves multiband performance at GSM850/900/1800/1900 and UMTS

Analysis and design of antennas for wireless communications using modal methods

El diseño de antenas para los nuevos sistemas de comunicaciones inalámbricas ha suscitado un creciente interés en los últimos años. El principal objetivo de esta Tesis Doctoral es la propuesta de un método general de diseño de antenas para sistemas de comunicaciones inalámbricas que proporcione una visión física del proceso de diseño. Para alcanzar este objetivo, se propone el uso de un método basado en la descomposición modal de la corriente en la superficie del cuerpo conductor. Los modos tienen la ventaja de proporcionar una visión más física del comportamiento radiante de la antena, así como información muy útil para la optimización de la geometría de la antena y para la selección del mecanismo óptimo de alimentación y su localización. En la Tesis se realizará una revisión de los diferentes métodos modales disponibles, así como de los parámetros más importantes a tratar cuando se trabaja con soluciones modales. Además, se investigará un método para obtener expresiones cerradas para las corrientes superficiales en objetos conductores planos abiertos. Como se verá, los objetos planos con formas canónicas se pueden interpretar en muchas ocasiones como deformaciones de objetos tridimensionales cuyas superficies coinciden con las de algunos de los sistemas de coordenadas curvilíneas. De esta forma, se obtendrán expresiones cerradas para los modos vectoriales en un disco conductor circular y una tira plana infinita. Estas funciones se propondrán como funciones base de dominio completo en problemas más complejos que incluyan este tipo de superficies planas. Los modos de corriente definidos a partir de las funciones de onda vectoriales son de naturaleza compleja, lo que dificulta en ocasiones su uso para el diseño de antenas. Por el contrario, la Teoría de los Modos Característicos proporciona una descomposición de la corriente total en la superficie de un cuerpo conductor de forma arbitraria en un conjunto de modos reales, cuyos diagramas de radiación son ortogonalesAntonino Daviu, E. (2008). Analysis and design of antennas for wireless communications using modal methods [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/2188Palanci

Ground plane booster antenna technology for wireless handheld devices

This thesis is framed in the field of mobile communications and more particularly in handset antennas. The wireless industry is constantly growing, which entails challenging handset antenna specifications. Handset antennas not only have to be multi-band for satisfying the great number of communication services, but also sufficiently small as for fitting in the reduced space imposed by the handset platforms. The appearance of the MIMO (Multiple Input Multiple Output) technology, further exacerbates these challenges. In order to satisfy these requirements, this thesis proposes the use of the ground plane, inherently present in any handset platform, as the main radiator. Electrically small nonresonant elements, called along this thesis as ground plane boosters, are used to transfer energy to this ground plane. The solution removes the need of including a dedicated antenna featured by considerable dimensions, thus releasing space to integrate other antennas, as well as, other handset components, services and functionalities.Postprint (published version

Design, Fabrication, and Measurement of a Multiple-Input Multiple-Output (MIMO) Antenna for Mobile Communication

This thesis presents the design, fabrication and characterization of a multiband uniplanar MIMO antenna for hand-held mobile communication devices on LTE, WLAN, and WMAN networks. The antenna design methodology combined a variety of broadbanding techniques that resulted in a single-layer hybrid monopole antenna coupled to a meander line element and parasitic structures. The 115×55×1.54 mm antenna was fabricated using an FR4 composite material and occupies only a fractional volume within the size of an average cellular phone allowing ample space to integrate with existing hardware. Characterization of the MIMO antenna included input impedance, scattering parameters and radiation pattern cross sections that were all measured from 500-6500 MHz inside an anechoic chamber. The measurement results indicated four main operating regions of the multiband antenna centered at 875 MHz, 2300 MHz, 3500 MHz, and 5700 MHz with bandwidths of 240 MHz, 740 MHz, 190 MHz, and 370 MHz respectively. Scattering parameter measurements demonstrated excellent coverage of the desired communication spectrum, being able to operate on 30 of the 42 defined LTE bands, as well as common WLAN and WMAN bands. The radiation pattern cross sections in each of the operating regions showed non-directional behavior that is desirable for mobile communication devices. Additionally the envelope correlation coefficient calculated from the measured complex scattering parameters verified that the MIMO antenna achieved good system diversity. Overall, this work resulted in a multiband uniplanar MIMO antenna system suitable for hand-held mobile communication devices. Utilizing cost effective materials and simple geometries allowed fabrication using common methods. The novel antenna can support the high capacity required from evolving communication systems and represents a practical option for use within future generations of mobile devices

Bandwidth enhancement technique for broadside tri-modal patch antenna

A technique for enhancing the bandwidth of a broadside tri-modal patch antenna is described. The key idea of the technique is to incorporate a dual-resonance structure into the broadside tri-modal patch geometry. By increasing one edge of the tri-modal patch while decreasing its size at the opposite edge, the resulting structure can be viewed as two super-imposed Y-shaped structures of different resonant frequencies. This intuition is confirmed using characteristic mode analysis (CMA). Furthermore, guided by CMA, further modificationsenable two sets of resonant modes to be tuned for increasing the bandwidth of the tri-modal patch antenna. Importantly, the proposed bandwidth enhancement technique does not affect the desired broadside radiation patterns significantly. Therefore, it can be utilized to modify the tri-modal patch antenna withoutdegrading its potential for massive MIMO array application. Measurement results show that the technique enhances the 10 dB impedance bandwidth from 4.3% to 19.7% with the largest antenna dimension of 0.48λc, where λc is the wavelength in air at the center frequency. The design example of the proposed technique is able to cover widely used 3 GHz bands in 5G communication systems and its potential usage in massive MIMO arrays is demonstrated

Antennas and Arrays for Mobile Platforms -- Direct Broadcast Satellite and Wireless Communication

Flexibility of any proposed communication links is becoming one of the most challenging features. Direct broadcasting satellite services, for example, will be greatly enhanced by providing service-on-the-move. This market is very demanding as it necessitates the development of a low cost, low profile antenna that can be mounted on top of SUVs and minivans, which is capable of continuously tracking the satellite. Another example is the wireless antennas for laptops and smart-phones, where the antennas should fit within an extremely small volume and should be capable of addressing many services over wide frequency range. In this dissertation, both DBS and the wireless antennas are addressed. In these studies, efforts have been concentrated in developing low profile planar antennas, in particular, slot arrays. Travelling wave slotted waveguide arrays have been utilized to minimize the scanning angle range limits due to their inherent beam tilt angle. CNC machines were utilized first to fabricate the early prototypes for sub-array developments. Subsequently, a low cost fabrication technology is adopted to develop a low cost and light weight full array using substrate integrated waveguides (SIWs). The SIW is fully characterized and an excellent equivalent model has been derived to allow easy translation of metallic waveguide components to SIW. Various SIW junctions, transitions, and arrays have been developed for array feed networks including a 64 radiating SIW full array and a 32 radiating SIW array with folded feed. Meanwhile, for the wireless antennas, the utilization of reconfigurable hardware has been introduced to provide the required multi-functionality services and wide frequency coverage. Various reconfigurable antennas were developed and utilized to demonstrate their advantages compared to other design options such as wide-band or multi-band approaches. Both micro-electro-mechanical switches MEMS and PIN diodes have been successfully utilized to switch between the different configurations. The placement, control, and modeling of the switches are also discussed and novel modeling and biasing topologies are introduced. A novel and practical concept of reconfigurable multiband antenna is introduced here too, where advantages of both the multi-band and the reconfigurable antenna structures can be simultaneously achieved while supporting more services

Ground plane booster antenna technology for wireless handheld devices

This thesis is framed in the field of mobile communications and more particularly in handset antennas. The wireless industry is constantly growing, which entails challenging handset antenna specifications. Handset antennas not only have to be multi-band for satisfying the great number of communication services, but also sufficiently small as for fitting in the reduced space imposed by the handset platforms. The appearance of the MIMO (Multiple Input Multiple Output) technology, further exacerbates these challenges. In order to satisfy these requirements, this thesis proposes the use of the ground plane, inherently present in any handset platform, as the main radiator. Electrically small nonresonant elements, called along this thesis as ground plane boosters, are used to transfer energy to this ground plane. The solution removes the need of including a dedicated antenna featured by considerable dimensions, thus releasing space to integrate other antennas, as well as, other handset components, services and functionalities

Antennit metallikuorisissa matkapuhelimissa

This master’s thesis studies the effects of a slotless, continuous metal cover of a mobile terminal on the performance of its antennas. Additionally, LTE MIMO antennas are designed together with GPS and Wi-Fi antennas. The cellular antennas should operate on 704–960MHz and 1.71–2.69 GHz with at least 30% efficiency, and the other antennas at 1.575 GHz, 2.4 GHz, and 5 GHz bands with 40% efficiency. The topic is studied by completing electromagnetic simulations. The used model of the mobile phone is much more accurate than the ones used in earlier studies. The simulations focus on the antenna structures, locations, and sizes, as well as feeding of them. Additionally, matching circuits are investigated, and designed for each antenna. The effect of the metal cover is studied with several test cases, each of which focuses on one parameter, e.g. a dimension, location, or feed of the antenna. The first simulations are done with a simple model, and a concept for the cellular antennas is constructed on the basis of the obtained results. The final simulations are completed, and the antennas optimized with the accurate model. The proposed structure consists of three closely located, strongly coupling elements. The cellular antennas are at distinct ends of the device, and integrated into the side metals. GPS and Wi-Fi antennas are also integrated into the sides, and placed in the area between the ends of the phone. The main challenge due to the metal-cover is obtaining sufficient and wideband matching. Regardless the challenging environment, all the designed antennas fulfill their requirements. Based on the results, achieving a good antenna performance in a metal-covered phone is not impossible.Tässä diplomityössä tutkitaan matkapuhelimen yhtenäisen metallikuoren vaikutusta antennien suorituskykyyn. Työssä suunnitellaan myös LTE-taajuuksilla toimiva MIMO-antenni sekä GPS- ja Wi-Fi-antennit. Matkapuhelinantennien tulee toimia taajuuksilla 704–960MHz ja 1.71–2.69 GHz vähintään 30 % hyötysuhteella. Vastaavasti muiden antennien taajuuskaistat ovat 1.575 GHz, 2.4 GHz ja 5 GHz tavoitehyötysuhteen ollessa 40 %. Tutkimus suoritetaan sähkömagneettisilla simulaatioilla. Työssä käytettävä puhelimen simulointimalli on paljon realistisempi kuin aiemmissa tutkimuksissa käytetyt mallit. Simuloinnit keskittyvät antennirakenteisiin sekä niiden sijainteihin, kokoihin ja syöttötapoihin. Lisäksi jokaiselle antennille suunnitellaan sovituspiiri. Metallikuoren vaikutusta tutkitaan useilla eri testeillä, joista jokainen keskittyy yhteen parametriin kuten antennin mittoihin, sijaintiin tai syöttöön. Työ aloitetaan yksinkertaisella simulointimallilla, ja näiden testien perusteella valitaan puhelinantennirakenne. Lopulliset testit ja antennien optimointi tehdään tarkalla mallilla. Esitetty rakenne koostuu kolmesta lähekkäin olevasta ja voimakkaasti kytkevästä antennielementistä. Puhelinantennit sijaitsevat laitteen eri päissä ja ovat osa puhelimen sivuissa olevaa metallirengasta. GPS- sekä Wi-Fi-antennit ovat myös osa metallirengasta ja sijaitsevat laitteen päätyjen väliin jäävällä alueella. Suurin metallikuoresta aiheutuva haaste on riittävän hyvän ja laajakaistaisen sovitustason saavuttaminen. Vaikeasta ympäristöstä huolimatta suunnitellut antennit täyttävät asetetut suorituskykytavoitteet. Tulosten perusteella on mahdollista suunnitella hyvin toimivat antennit metallikuoriseen puhelimeen