Multiband handset antenna with a parallel excitation of PIFA and slot radiators

A handset antenna technique combining a parallel excitation of a PIFA and a slot is presented. The number of frequency bands is given by the sum of bands given per each radiator which can be controlled independently. Component interaction (battery, display, and speaker) is analyzed to determine the best place to mitigate performance degradation. Finally, a concept featuring a small footprint (39 11 mm) and low profile (2 mm) is proposed for multiband operation.A handset antenna technique combining a parallel excitation of a PIFA and a slot is presented. The number of frequency bands is given by the sum of bands given per each radiator which can be controlled independently. Component interaction (battery, display, and speaker) is analyzed to determine the best place to mitigate performance degradation. Finally, a concept featuring a small footprint (39 11 mm) and low profile (2 mm) is proposed for multiband operation.Postprint (published version

Mobile-phone antenna design

published_or_final_versio

Experimental studies of small antennas for mobile communications.

by Shu-chuen Lee."Revised : September 1994."Thesis (M.Phil.)--Chinese University of Hong Kong, 1994.Includes bibliographical references (leaves 61-62).Acknowledgment --- p.iLists of Illustration --- p.iiChapter Chapter 1 --- Introduction --- p.1Chapter 1.1 --- References --- p.4Chapter Chapter 2 --- The Meandering Inverted-F Antenna --- p.5Chapter 2.1 --- Evolution of the antenna --- p.6Chapter 2.2 --- The first prototype --- p.10Chapter 2.2.1 --- Geometry of the first prototype --- p.10Chapter 2.2.2 --- Resonant frequency --- p.12Chapter 2.2.3 --- Bandwidth --- p.16Chapter 2.3 --- Antenna with longer meandering line --- p.17Chapter 2.4 --- Antenna loaded with dielectric substrate --- p.20Chapter 2.4.1 --- Frequency characteristics --- p.21Chapter 2.4.2 --- Radiation pattern measurements --- p.22Chapter 2.4.3 --- Radiation patterns --- p.26Chapter 2.5 --- The 1.9GHz antenna --- p.34Chapter 2.6 --- Summary --- p.36Chapter 2.7 --- References --- p.37Chapter Chapter 3 --- The Meandering Posted Microstrip Antenna --- p.38Chapter 3.1 --- Introduction --- p.39Chapter 3.2 --- Theory --- p.40Chapter 3.3 --- Meandering Inverted-F antenna implemented on PCB --- p.44Chapter 3.3.1 --- Geometry for the antenna --- p.44Chapter 3.3.2 --- Microstrip bends --- p.45Chapter 3.3.3 --- Frequency characteristics --- p.47Chapter 3.3.4 --- Implementation of the microstrip antenna with different line width --- p.49Chapter 3.3.5 --- Radiation patterns --- p.51Chapter 3.4 --- Physical realization --- p.58Chapter 3.5 --- Summary --- p.60Chapter 3.6 --- References --- p.61Chapter Chapter 4 --- Conclusions --- p.6

Mobile-phone antenna design

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A Multiband Printed Antenna Suitable for Wireless Applications

This study deals with a new research work on a low cost multiband printed antenna which can be used for three operating frequency bands GSM900/PCS/WIFI/Bluetooth. The achieved antenna is mounted on an FR-4 substrate. In this study, the solts technique is used to obtain the multiband behavior. The different solts are inserted in the radiator face and the back face that is the ground. The whole circuit is optimized taking into account the good matching of the input impedance in the operating frequency bands with a stable radiation pattern. In order to optimize the proposed antenna structure we have used CST-MW and to compare the obtained simulation results we have conducted another electromagnetic simulation by using HFSS solver. The final circuit validated into simulation has been fabricated and tested which permits to validate the proposed multiband antenna

Multiple frequency band and high isolation mobile device antennas using a capacitive slot

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Design of high-efficiency antennas for mobile communications devices

This thesis deals with the design of high-efficiency antennas for small mobile communications devices. Owing to the continuously stricter requirements set for multisystem mobile terminals, the ongoing need for efficient antennas in personal mobile communications is evident. In this work, the entire system consisting of the antenna; the mobile terminal working actually as part of the antenna; and the user of the terminal is considered. The ratio between the power radiated into the free space and the antenna input power, i.e. the total efficiency of this system, forms a general concept for the studies. The total efficiency is partly affected by the losses in the antenna element. As the antenna efficiency, bandwidth, and volume are strongly interrelated exchangeable quantities, it is essential to find other approaches for enhancing the antenna efficiency than simply sacrificing other performance. Further, the metal chassis of a mobile terminal has to be part of the antenna element design because of its considerable effect on antenna performance. In addition, the total efficiency of the entire system is partly affected by the losses owing to the user. Thus, the evaluation of antenna performance is equally important when the mobile terminal is located near a user or when it is in free space. The main goal of this work is to provide novel and useful information for the design of mobile terminal antennas with special emphasis placed on the maximization of the total efficiency. To obtain necessary background understanding for the design of antennas with minimized user interaction, the general energy-absorption mechanism in the human tissue is studied in this thesis. It is shown that the peak SAR (specific absorption rate) is not actually related to the antenna current, as has been commonly believed. Instead, the SAR maximums can be explained by inspecting the antenna's quasi-static electric near field components perpendicular and parallel to the surface of the tissue at the air-tissue interface and utilizing the boundary conditions of quasi-static fields at the interface. As SAR is directly proportional to the total electric field in the tissue, the SAR distributions caused by a certain antenna differ considerably in tissues with different permittivity values, e.g. brain and fat. The bandwidth, efficiency in talk position, and SAR performance of a typical monoblock handset antenna-chassis combination is comprehensively investigated in this work for clarifying the roles of different parts of the radiating system. The system is treated as a combination of the separate wavemodes of the antenna element and the chassis. Based on the results, guidelines are given to control or analyze the combined performance both in the sense of radiation properties (bandwidth, efficiency) and user interaction (SAR). It is also demonstrated that there is a connection between the studied three performance parameters: a local maximum in SAR values and a local minimum in radiation efficiency occur when the bandwidth reaches its maximum and the resonant frequency of the chassis equals that of the antenna. The suitability of dielectric resonator antennas (DRA) for mobile terminals is studied theoretically and experimentally with the main attention paid to the loss characteristics. It is observed that DRAs are appropriate for this purpose especially when very small antenna elements are needed. As an application example, a novel means to realize a high-performance dual-resonant antenna design for mobile terminals is presented. In addition, losses in the frequency-tuning circuits of small resonant antennas are systematically investigated. Design guidelines for tuning circuits with minimized losses with respect to the achievable tuning range are given. Based on the proposed theory, a low-loss tuning circuit with suitable characteristics for mobile terminal antennas is introduced.reviewe

Steady-State Analysis of a Directional Square Lattice Band-Edge Photonic Crystal Lasers

The original square-lattice band-edge structure emitted light in different directions. In a recent paper, we have improved the directivity of these structures by using a honeycomb photonic crystal to shield the original structure. This has improved the performance of such devices, in such a way that light can be coupled directionally to a large waveguide. In this paper, we present a steady-state analysis of the performance of this directive device and study the amount of power which can be coupled into the waveguide, analyzing its performance as an in-plane emitter and the limitations caused by vertical losses

A study of planar inverted-F antennas in a dielectric enclosure

Demand for small and low-profile antennas has greatly increased due to the desire for miniaturisation of modern-day mobile radio electronic terminals. Such an antenna is often integrated into the dielectric casing of a terminal, or independently enclosed within a dielectric radome to provide a protection from operating environments and keep the system more compact. However, the dielectric casing or radome may interact strongly with the antenna and result in losses in performance. The primary focus of this dissertation is to investigate and enhance the performance of Planar Inverted-F Antennas (PIFAs) when enclosed in dielectric casings or radomes for applications in mobile radio communications. PIFAs have attracted much interest due to their small volume, low profile structures and electrical characteristics compatible with existing specifications, making it a promising candidate for mobile radio applications. Therefore, the design of a single band PIFA on a finite ground plane, operating in the 900 MHz band is first presented. It is found that the effect of the finite ground plane must be considered to achieve an optimum performance of the PIFA. Then the performance of this antenna in the presence of a dielectric cover layer is investigated and evaluated in terms of resonant frequency, bandwidth and efficiency. In this study, the dielectric layer represents the dielectric casing of a device where the antenna is much closer to the top part of the casing than to the other side parts whose effect can then be ignored. Computer simulations of performance are based on the Method of Moments (MOM) and have been validated by measurements. This study shows that a dielectric cover layer will strongly interact with the antenna with the result that the antenna performance may move outside the design specifications.Therefore, it is concluded that the dielectric cover layer must always be taken into account in the design stage. In addition, the input and radiation characteristics of a PIFA enclosed within a rectangular dielectric radome for both the 900 MHz and 2400 MHz frequency bands are analysed using the MOM. This research concentrates on the effect of each individual part of the rectangular dielectric radome on the overall performance. It is observed that each individual part has a different degree of effect on both the input and radiation characteristics of the PIFA, and that the effect is more significant at the higher frequency band. The study indicates that the effect of the dielectric radome on the performance of the antenna can be minimised by carefully choosing its location and orientation within the radome. Another indication is that an optimised dielectric radome design can both miniaturise the antenna and at the same time improve the bandwidth without sacrificing other performance parameters such as the gain. Furthermore, an analytical approach based on the Transmission Line Model (TLM) is applied to estimate the input characteristics of a PIFA having a dielectric cover layer. The results calculated based on this approach are compared with MOM computed results. A reasonably good agreement between them has been demonstrated. It is suggested that the TLM model could form part of an efficient Computer Aided Design (CAD) tool for design engineers to provide initial design parameters.Finally, a new dual-band PIFA is proposed. A design example for the Industrial, Scientific and Medical (ISM) frequency bands of 900 MHz and 2400 MHz is given. Measurement validation of the design is presented. The influence of the dielectric cover layer on the resonant frequency, bandwidth, gain and radiation patterns of this antenna is also examined by simulation. In this study, it is found that a simple capacitive disk arrangement not only provides a single feed for dual-band operation but also gives flexibility to allow individual control of the two desired band resonances