U-Shaped Microstrip Patch Antenna for WLAN/WIMAX Applications

A full-duplex radio design communication systems design based on the WiMax/WLAN antenna. The design an antenna in this report presented a triple-band operation with significant impedance bandwidth for WLAN/WiMAX system. The designed antenna having the compact size of 10 x 26 mm2 and shaped of antenna is U-shaped. The overall performance of the antenna three different bands 1) band-1:- 2.40 to 2.53 GHz, 2) band-2:-3.40 o 3.60 GHz and 3) band-3:- 5.00 to 6.00 GHz, these bands cover the WiMAX (2.5, 3.5, 5.5) and WLAN (2.4, 5.2, 5.8) bands. Here HFSS simulator used to simulate and validate the results. By combining the performance of complete WLAN/WiMAX antenna with MIMO antenna, the proposed MIMO antenna with wide operating frequencies 2.4 GHz. Thus the simulation results along with the given parameter values show that the antenna can simultaneously operate over WLAN, WiMAX and MIMO frequency bands

Balanced antennas for mobile handset applications. Simulation and Measurement of Balanced Antennas for Mobile Handsets, investigating Specific Absorption Rate when operated near the human body, and a Coplanar Waveguide alternative to the Balanced Feed.

The main objectives of this research are to investigate and design low profile antennas for mobile handsets applications using the balanced concept. These antennas are considered to cover a wide range of wireless standards such as: DCS (1710¿1880 MHz), PCS (1850¿1990 MHz), UMTS (1920¿2170 MHz), WLAN (2400¿2500 MHz and 5000 ¿ 5800 MHz) and UWB frequency bands. Various antennas are implemented based on built-in planar dipole with a folded arm structure. The performance of several designed antennas in terms of input return loss, radiation patterns, radiation efficiency and power gain are presented and several remarkable results are obtained. The measurements confirm the theoretical design concept and show reasonable agreement with computations. The stability performance of the proposed antenna is also evaluated by analysing the current distribution on the mobile phone ground plane. The specific absorption rate (SAR) performance of the antenna is also studied experimentally by measuring antenna near field exposure. The measurement results are correlated with the calculated ones. A new dual-band balanced antenna using coplanar waveguide structure is also proposed, discussed and tested; this is intended to eliminate the balanced feed network. The predicted and measured results show good agreement, confirming good impedance bandwidth characteristics and excellent dual-band performance. In addition, a hybrid method to model the human body interaction with a dual band balanced antenna structure covering the 2.4 GHz and 5.2 GHz bands is presented. Results for several test cases of antenna locations on the body are presented and discussed. The near and far fields were incorporated to provide a full understanding of the impact on human tissue. The cumulative distribution function of the radiation efficiency and absorbed power are also evaluated.UK Engineering and Physical Sciences Research Council (EPSRC

Fixed and reconfigurable multiband antennas

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityWith the current scenario of development of antennas in the wireless communication field, the need of compact multiband, multifunctional and cost effective antenna is on the rise. The objective of this thesis is to present fixed and reconfigurable techniques and methods for small and slim multiband antennas, which are applicable to serve modern small and slime wireless, mobile and cognitive radio applications. In the fixed designs, independent control of the operating frequencies is investigated to enhance the antennas capabilities and to give the designer an additional level of freedom to design the antenna for other bands easily without altering the shape or the size of the antenna. In addition, for mobile phone antenna, the effect of user’s hand and mobile phone housing are studied to be with minimum effect. Although fixed multiband antennas can widely be used in many different systems or devices, they lack flexibility to accommodate new services compared with reconfigurable antennas. A reconfigurable antenna can be considered as one of the key advances for future wireless communication transceivers. The advantage of using a reconfigurable antenna is to operate in multiband where the total antenna volume can be reused and therefore the overall size can be reduced. Moreover, the future of cell phones and other personal mobile devices require compact multiband antennas and smart antennas with reconfigurable features. Two different types of frequency reconfigurability are investigated in this thesis: switchable and tunable. In the switchable reconfigurability, PIN diodes have been used so the antenna’s operating frequencies can hop between different services whereas varactor diode with variable capacitance allow the antenna’s operating frequencies to be fine-tuned over the operating bands. With this in mind, firstly, a switchable compact and slim antenna with two patch elements is presented for cognitive radio applications where the antenna is capable of operating in wideband and narrow bands depending on the states of the switches. In addition to this, a switchable design is proposed to switch between single, dual and tri bands applications (using a single varactor diode to act as a switch at lower capacitance values) with some fine tuning capabilities for the first and third bands when the capacitance of the diode is further increased. Secondly, the earlier designed fixed antennas are modified to be reconfigurable with fine-tuning so that they can be used for more applications in both wireless and mobile applications with the ability to control the bands simultaneously or independently over a wide range. Both analytical and numerical methods are used to implement a realistic and functional design. Parametric analyses using simulation tools are performed to study critical parameters that may affect the designs. Finally, the simulated designs are fabricated, and measured results are presented that validate the design approaches

Design and Analysis of Various Handset Antennas with the Aid of HFSS

In this thesis, an attempt is made to present the design of handset antennas, the proposed handset acts as a thin wire model that represents the backbone of the final antenna. The designed antenna parameters are subjected to optimization to fit into the desired frequency bands. Different antenna types are used, such as wire antennas and planar antennas designed using theHFSS.The design of basic antennas for handset applications, experimented with a simple monopole and dipole in a 3-D form. The monopole and dipole used in handset antennas provides multi-band and broadband properties that cover the desired frequency bands in the handset antennas. The design experiment and analysis of a continuous and unbroken metal rimmed antenna with a monopole which is directly fed with a patch acts as aloo antenna in smart phone applications is proposed. The antenna proposed here provides a straight forward and a good multi-band antenna result for anprotected metal rimmed smart phone. The protected rim and two no-ground portions are set on the both the top and bottom sides of the system circuit board, respectively. The system ground is surrounded between the two no ground portions which are connected to the metal rim with a small grounded patch which divides the unbroken metal rim into two strips. Atlast the dualloop antenna is formed by adjusting the ground plane and the micro strip ina proper way. The design antenna is operated on several number of GSM bands.The second design is study of a balanced antenna with folded architecturefor mobile handset applications with dual-frequency performance (2.40 GHzand 5.00 GHz) for WLAN applications are discussed. The thin-strip planardipole is used as an antenna with folded architecture and two arms on eachmonopole. The folded architectures one on the left and other on the rightacts as a dipole and are capable of providing the multiple bands .The antenna performance is featured by using the antenna radiation pattern,returnloss, power gain and surface current distribution of the antenna. The parametric studies are carried out by varying the antenna height and width of1 mm each, the parameters are optimized for steered impedance matchingwithin the range of frequency bands for both the WLAN and short distance communication systems.The third design is focused on the frequency band (1.8 GHz to 2.45 GHz)in which the balanced antenna for applications of mobile handsets with abandwidth of highly improved performance. The slot planar dipole is usedan antenna here with folded architecture and is having a dual arm on boththe sides of the ground plane. The S-parameter method is used to findthe antenna impedance. In order to obtain the power gain measurementin the antenna.The balanced feed from an unbalanced source is supportedby planar balun which is of wide bandwidth to get the desired gain. The results measured provides a good agreement and also provides good wideband characteristic

MIMO ANTENNAS FOR MOBILE HANDSET AND TABLET APPLICATIONS.

PhDThe fast development of wireless communication technologies is pressing the antenna engineers to investigate and design compact multiband antennas for the multiple-input multiple-output (MIMO) systems, which is the key technology for the next generation of mobile communications. The growing increase in the demand for transmitting and exchanging large volume data, such as multimedia and interactive materials is constantly fueling the need for higher data rates. MIMO systems have demonstrated the capability to increase channel capacity, with a simultaneous increase in range and reliability, without taking any additional bandwidth thus resulting in improved data throughput. However, the performance of a MIMO system is highly dependent on the nature of its propagation environment and the placement of antennas on device platform. The true benefits of MIMO can be exploited through a smart design that can adapt with changing system requirements or environmental conditions. This research project has investigated the methods to make multiband MIMO and multiband reconfigurable antennas on small mobile terminals with high communication performance. This involves the methods for avoiding coupling between multiple antennas and possible tuning of the antennas for next generation mobile handsets. The aim of this work is to develop MIMO and reconfigurable antennas for wireless terminals such as mobile handsets and tablets. The project is divided in two phases with the first phase involving the development of multiband MIMO antennas for handheld terminals and the second phase involves the design of reconfigurable antenna for mobile handsets. Several prototypes of handset antennas, capable of covering various cellular frequency bands, have been developed. The research involves a substantial work on theoretical analysis, computer simulation and experimental verification

Performance investigation of vertical axis wind turbine with savonius rotor using Computational Fluid Dynamics (CFD)

The quest of clean and sustainable energy has grown rapidly all over the world in the recent years. Among the renewable energy resources available, wind energy is considered one of the reliable, environmentally friendly, green and fastest-growing source of electricity generation. This generation is accomplished through wind turbines. However, the efficiency of these wind turbines is still very limited and unsatisfactory. The primary goal of this study is to evaluate the performance of a Savonius rotor wind turbine in terms of aerodynamic characteristics, including torque, torque coefficient, and power coefficient. The design of Savonius wind turbine blades is varied and its effects is observed. The simulation models are developed using a modeling software known as Solidworks 2021 and then generated into Ansys Design Modeler 2021 R1 to define the fluid domain. In total, three distinct turbine blades are modelled while varying the diameter and height of the rotor. The simulation study is performed using FLUENT 2021 R21. A constant wind speed value of 9.2 m/s has been used throughout the simulation. The simulation was carried out using a transient time flow with a constant upstream wind speed. The results have shown that the power coefficient of all models increases with TSR and the highest efficiency is consensually obtained at almost a unity (0.9) TSR. Comparing the performance of all models, Model 2 generates the highest power coefficient followed by Model 3 and Model 1, respectively. In terms of power, torque and torque coefficient, nearly similar conclusion is drawn

Wideband and UWB antennas for wireless applications. A comprehensive review

A comprehensive review concerning the geometry, the manufacturing technologies, the materials, and the numerical techniques, adopted for the analysis and design of wideband and ultrawideband (UWB) antennas for wireless applications, is presented. Planar, printed, dielectric, and wearable antennas, achievable on laminate (rigid and flexible), and textile dielectric substrates are taken into account. The performances of small, low-profile, and dielectric resonator antennas are illustrated paying particular attention to the application areas concerning portable devices (mobile phones, tablets, glasses, laptops, wearable computers, etc.) and radio base stations. This information provides a guidance to the selection of the different antenna geometries in terms of bandwidth, gain, field polarization, time-domain response, dimensions, and materials useful for their realization and integration in modern communication systems

Antenna integration for wireless and sensing applications

As integrated circuits become smaller in size, antenna design has become the size limiting factor for RF front ends. The size reduction of an antenna is limited due to tradeoffs between its size and its performance. Thus, combining antenna designs with other system components can reutilize parts of the system and significantly reduce its overall size. The biggest challenge is in minimizing the interference between the antenna and other components so that the radiation performance is not compromised. This is especially true for antenna arrays where the radiation pattern is important. Antenna size reduction is also desired for wireless sensors where the devices need to be unnoticeable to the subjects being monitored. In addition to reducing the interference between components, the environmental effect on the antenna needs to be considered based on sensors' deployment. This dissertation focuses on solving the two challenges: 1) designing compact multi-frequency arrays that maintain directive radiation across their operating bands and 2) developing integrated antennas for sensors that are protected against hazardous environmental conditions. The first part of the dissertation addresses various multi-frequency directive antennas arrays that can be used for base stations, aerospace/satellite applications. A cognitive radio base station antenna that maintains a consistent radiation pattern across the operating frequencies is introduced. This is followed by multi-frequency phased array designs that emphasize light-weight and compactness for aerospace applications. The size and weight of the antenna element is reduced by using paper-based electronics and internal cavity structures. The second part of the dissertation addresses antenna designs for sensor systems such as wireless sensor networks and RFID-based sensors. Solar cell integrated antennas for wireless sensor nodes are introduced to overcome the mechanical weakness posed by conventional monopole designs. This can significantly improve the sturdiness of the sensor from environmental hazards. The dissertation also introduces RFID-based strain sensors as a low-cost solution to massive sensor deployments. With an antenna acting as both the sensing device as well as the communication medium, the cost of an RFID sensor is dramatically reduced. Sensors' strain sensitivities are measured and theoretically derived. Their environmental sensitivities are also investigated to calibrate them for real world applications.Ph.D.Committee Chair: Tentzeris, Emmanouil; Committee Member: Akyildiz, Ian; Committee Member: Allen, Mark; Committee Member: Naishadham, Krishna; Committee Member: Peterson, Andrew; Committee Member: Wang, Yan