Abstract In this paper, an algorithm for accurately finding the position, orientation and dipole moment of a transmitting dipole antenna buried in rock is presented. The algorithm is based on simplified radiation equations that are shown to be valid within a region of space in the extreme near field surrounding the antenna called termed quasi-static region. Within this region, medium dependent propagation effects are negligible, allowing accurate, medium independent resolution of position, orientation and dipole moment. The magnetic field magnitude and direction values observed at a number of arbitrarily located points in space are used by the algorithm to generate a system of nonlinear equations. This system of equations is solved using a simultaneous multi-variable Newton-Raphson solver with line searches and backtracking providing a measure of global convergence. An additional method, based on an iterated random search, further improves the global convergence capability of the algorithm. If the dipole moment of the transmitting antenna is known, measurements from two observer points are sufficient to resolve the position and orientation of the dipole. If the dipole moment is unknown, three observer points are required to solve for the unknown position, orientation and dipole moment. The algorithm is able to find an exact solution using exact theoretical measurements, and a minimised least squares solution where measurements are subject to noise. The theory relating to the algorithm is discussed including distance-frequency relations for the quasistatic region of a number of common rock types. Probabilistic modelling, simulation and test results of the algorithm are also included.

Yes / A printed dipole antenna integrated with a duplex RF switch used for mobile base station antenna beam steering is presented. A coplanar waveguide to coplanar strip transition was adopted to feed the printed dipole. A novel RF switch circuit, used to control the RF signal fed to the dipole antenna and placed directly before the dipole, was proposed. Simulated and measured data for the CWP-to-CPS balun as well as the measured performance of the RF switch are shown. It has demonstrated the switch capability to control the beam in the design of beam steering antenna array for mobile base station applications.

In this work, we discuss the accuracy of measurements for electromagnetic. The two kinds of antenna we use are Dipole antenna and Broadband antenna. In general, if the antenna measurements we recorded at different frequencies do not exceed the ideal value $pm 4$dB, we would regard this site as a normalized site, otherwise it is not a normalized site(just a measurement exceeds the range). Traditionally, all we use is Dipole antenna, but due to difficulty of operation and inaccuracy of Dipole antenna, we investigate by statistical methods if we may use the Broadband antenna to replace the traditional Dipole antenna to measure. First of all, we introduce the data and procedure in the experiments, and fit a statistical regression model to predict the measurements at different frequencies in different test setups. Then, according to the data we collected, use the change point models to modify the statistical models. Our goal is to find a suitable statistical model for the measurements. Finally, we compare the measurements of Broadband antenna with Dipole antenna in the other experimental conditions keep the same.

Yes / In this paper, a balanced antenna for mobile handset applications with enhanced bandwidth performance, that covers four bands (GSM1800, GSM1900, UMTS and 2.4-GHz WLAN), is investigated. The antenna is a slot planar dipole with folded structure and a dual-arm on each monopole. A wide bandwidth planar balun is employed to feed the wideband balanced antenna from an unbalanced source. A prototype of the proposed antenna is fabricated and tested. The performance of the antenna is veri¯ed and characterized in terms of return loss, radiation patterns and power gain. The calculated and measured results show good agreement and also con¯rm good wideband characteristics for the proposed antenna with multiband operation.

Yes / In this paper, a planar multiple input, multiple output (MIMO) dipole antenna for a future sub-6 GHz 5G application is proposed. The planar MIMO structure consists of 4 antenna elements with an overall size of 150×82×1 mm3. The single antenna element is characterized by a size of 32.5×33.7×1 mm3 printed on an FR-4 dielectric substrate with εr=4.4 and tanδ=0.02. The suggested antenna structure exhibits good impedance bandwidth equal to 3.24 GHz starting from 3.3 to 6.6 GHz with an S11 value of less than -10 dB (S11≤-10 dB) with antenna gain varying from 5.2 up to 7.05 dB in the entire band, which covers all the sub-6 GHz frequency band of the 5G application. Good isolation is achieved between the MIMO elements due to low surface waves inside the MIMO antenna substrate. The radiation of the MIMO antenna structure can be manipulated and many beam-types can be achieved as desired. The high-frequency structure simulator (HFSS) software package is used to design and simulate the proposed structure, while the CST MWS is used to validate the results.

The ocean symbolizes mystery, passion, and power. However, most of the ocean, about 80 %, is unknown to humans. AUVs (Autonomous Underwater Vehicles) provide a platform where terrain mapping, the biodiversity, and the resource survey of the ocean become accessible. Unlike ROVs (Remotely Operated Vehicle), AUVs operate according to their preset program which specifies the instructions required in different environments. One design aspects of AUVs that must be considered is that the data it acquire needs to be transmitted to a ground station (typically a ship). Although underwater acoustic communication is available nowadays, the low transmission rate and narrow bandwidth makes it unsuitable for large data transmission. For large sets of data, transmission with electromagnetic waves is more suitable. LoLo is an AUV which is designed and assembled at KTH Royal Institute of Technology, Sweden. Its wireless communication system consists of five components: RC (radio communication, 2.4 GHz), RF (radio frequency, 868 MHz), WIFI (wireless fidelity, 2.4 GHz), 4G (4th generation, 800 MHz, 1.8 GHz and 2.6 GHz) and GPS (global positioning system, 1.575 GHz). The goal of this project is to design an antenna board where the five subsystems are integrated. Importantly, due to the influence of seawater and waves, the resonant frequency of the antenna will fluctuate to a certain extent. Therefore, we need a robust, and preferably broadband, antenna system. In this project, we integrated printed dipole and monopole antennas on a single circuit board. The printed dipole antennas operate over a reasonable bandwidth and their radiation pattern is omnidirectional. The monopole antenna is designed to have multiple resonant frequencies which can cover BAND 20 (800 MHz) and BAND 3 (1.8 GHz) of the 4G service in Sweden. The 4G antenna shows good omnidirectional characteristics in the lower frequency band (band 20) and broadband characteristic in the higher frequency band. The upper 4G band is to be used to transmit large sets of data if a signal can be detected. The lower 4G band is added to provide redundancy. The antenna board is manufactured and measured. The results show the consistency with the simulation results and meets the requirement of the project. / Havet symboliserar mysterium, passion och kraft. Men det mesta av havet, cirka 80 %, är okänt för människor. AUVs (Autonomous Underwater Vehicles) är en plattform där terrängkartläggning, biologisk mångfald och resursundersökning blir tillgänglig. Till skillnad från ROVs (Remotely Operated Vehicles) fungerar AUVs enligt sitt förinställda program som specificerar de instruktioner som krävs i olika miljöer. Den data som den förvärvade måste överföras till en markstation (oftast en båt). Även om akustiska kommunikationen under vatten är möjlig idag gör den låga överföringshastigheten och den smala bandbredden den olämplig för stora dataöverföringar. I dessa fall är det bättre att överföra data med hjälp av elektromagnetiska vågor. LoLo är en AUV som är designad på KTH Royal Institute of Technology, Sverige. Dess trådlösa kommunikationssystem består av fem delsystem: RC (radiokommunikation, 2.4 GHz), RF (radiofrekvens, 868 GHz), WIFI (trådlös fidelity, 2.4 GHz), 4G (4 generationen av mobilnätverket, 800 MHz och 1.8 GHz) och GPS (global positioning system, 1.575 GHz). Målet med detta projekt är att designa antennerna för dessa fem delsystem. Viktigt att notera är antennernas resonansfrrekvens påverkas till viss del av havsvatten och vågor. Därför behövs vi ett robust, bredbandsantennsystem. I detta projekt integrerade vi dipolantenner och en monopolantenn på ett kretskort. Dipolantennerna har rimlig bandbredd och är omnidirektionella. Monopolantennen ger oss flera resonansfrekvenser som kan täcka Band 20 (800 MHz) och Band 3 (1.8 GHz) av 4Gspektrumet i Sverige. 4Gantennen visar omnidirektionella strålningsegenskaper i det lägre band et (band 20) och har vred bandbredd i det högre band et. Det högre bandet kommer användas för att skicka mycket data om en signal kan säkras. Det lägre bandet ger redundans. Antennen tillverkas och mäts i ett ekofritt rum. Mätresultaten stämmer överens med simuleringsresultaten och uppfyller projektets krav.

Traditional antennas have a lot of limitations as their performance is usually fixed by their initial geometry. On the other hand, modern communication systems are getting way to complicated compared to their earlier counterparts. This necessitates some special types of smart or reconfigurable antennas, which can dynamically adapt to the requirements of the communication systems more effectively. Using conventional single functional antennas is therefore not an efficient approach in these sort of communication systems. Considering all these factors, in this thesis, a beam steerable reconfigurable antenna system is presented that can yield the radiation patterns of multiple antennas with a single structure, necessary for 5G communication. This antenna system occupies comparatively much smaller space and can provide highly directive gain at different directions. It is expected that- in near future, further improvements of this type of antenna system can be performed to pave the way for some additional necessary functions required in modern communication systems.

In this thesis, two novel broadband slot mobile phone antenna designs respectively for penta-band WWAN operation and eight-band LTE/WWAN operation are presented. The antennas are suitable to be mounted near the bottom edge of the system ground plane of the mobile phone. Good radiation characteristics for the antennas are obtained, and the two antennas respectively occupy a small printed area of 50 ¡Ñ 4 mm2 and 53 ¡Ñ 4 mm2. The first design uses a C-shaped strip connected to the bottom edge of the system ground plane to make the structure of the system ground plane close to a symmetric shorted dipole antenna. This makes it promising to excite a chassis mode to enhance the operating bandwidth of the antenna. The second one uses a microstrip feedline having a chip-inductor-loaded branch. The novel microstrip feedline can lead to more uniform distribution of the electric fields excited in the slot such that enhanced bandwidth of the antenna¡¦s lower band is obtained. Further, since the chip inductor performs like a low-pass filter, the original bandwidth of the antenna¡¦s upper band is not affected. Additionaly, the impedance matching of the lower frequencies of the upper band can be improved, which enhances the upper-band bandwidth of the antenna. Effects of the user¡¦s head and hand on the proposed antenna are also studied, and the simulated SAR and HAC issues are also analyzed in this thesis.

In this thesis, the study mainly focuses on the terrestrial DTV signal reception antenna. These antennas are designed based on the use of planar dipole antenna, but with different techniques in order to overcome the narrow-bandwidth problem of conventional dipole antenna. In ¡§Broadband Three-arm Dipole Planar Antenna for DTV Signal Reception,¡¨ a metal plate is added for achieving wideband operation. In ¡§End-fed Modified Dipole Antenna for DTV Signal Reception,¡¨ two arms of different lengths are extended in the same direction to wideband operation. In ¡§Internal DTV Antenna for Folder-Type Mobile Phone,¡¨ two system ground planes are regarded as the two arms of the dipole. With the use of an internal matching circuit, good impedance matching can be obtained for receiving DTV signal over a wide bandwidth.

A six-band antenna design for the mobile phone is presented. The required bandwidth for DTV/GSM850/900/DCS/PCS/UMTS operation is achieved by using two antennas. For DTV/GSM850/900 operation, we propose a novel antenna by using the concept of the dipole antenna and an internal matching portion to excite the half- and one-wavelength resonant modes of the antenna. With the internal matching portion, the frequency ratio of the two resonant modes can be controlled, thereby making the two resonant modes formed into a very wide operating band. For DCS/PCS/UMTS operation, a novel monopole slot antenna is used. The lower-edge frequency of the slot antenna depends on its length and the required bandwidth can be achieved by adjusting its tuning section. Effects of casing and human body on the proposed mobile phone antenna are also discussed. It is found that the radiation efficiency of DTV/GSM bands is larger than that of DCS/PCS/UMTS bands in this design. However, overall the operating bands, the antenna performances are greatly affected when the human effects are taken into considerations.