1,976 research outputs found

    A Software Controlled Polarization and Pattern Reconfigurable Microstrip Parasitic Array Antenna for a Market Mediated Software Defined Communications System

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    Software Defined Radio (SDR) provides a platform for a reconfigurable communication system that is solely controlled by a software program with access to certain hardware modules. SDRs are typically connected to very minimalistic, and often, manually controlled reconfigurable antenna(s) with no software control over radiation parameters. Hence, on a wave propagation front, the radiator does not capitalize on the software infrastructure it is connected to. This thesis presents a software controlled pattern and polarization reconfigurable microstrip patch antenna, with reconfigurable parasitic elements, for reconfigurable wireless networks and applications. The antenna is designed to operate from 2.4 GHz to 2.5 GHz, covering all channels (channels 1 through 14) of the 2.4 GHz ISM band. This broadband behavior is achieved with a two-layer stacked annular ring patch antenna, separated by a layer of foam. This antenna is dual probe-fed to achieve vertical and horizontal linear polarizations as well as right-hand and left-hand circular polarizations. Pattern reconfiguration is achieved with a third layer composed of microstrip patch elements acting as parasitic radiators, either reflecting or directing a beam in a direction, which are controlled by RF PIN diodes. Elements are placed such that pattern reconfiguration is possible across all polarization modes. Various iterations of the design process are discussed along with their issues and solutions. Other reconfiguration techniques are also suggested as part of future work

    Reconfigurable Reflectarrays and Array Lenses for Dynamic Antenna Beam Control: A Review

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    Advances in reflectarrays and array lenses with electronic beam-forming capabilities are enabling a host of new possibilities for these high-performance, low-cost antenna architectures. This paper reviews enabling technologies and topologies of reconfigurable reflectarray and array lens designs, and surveys a range of experimental implementations and achievements that have been made in this area in recent years. The paper describes the fundamental design approaches employed in realizing reconfigurable designs, and explores advanced capabilities of these nascent architectures, such as multi-band operation, polarization manipulation, frequency agility, and amplification. Finally, the paper concludes by discussing future challenges and possibilities for these antennas.Comment: 16 pages, 12 figure

    Gain-Reconfigurable Hybrid Metal-Graphene Printed Yagi Antenna for Energy Harvesting Applications

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    This paper presents a hybrid metal-graphene printed Yagi antenna with reconfigurable gain that operates in the 5.5-GHz band. The balun and the driven elements are made of copper, while the directors are made of graphene. The graphene acts as a tunable material in the design. By switching the conductivity of the graphene, it is achieved a similar effect to adding or subtracting directors in the antenna. Hence the gain of the printed Yagi can be easily controlled. This could be of special interest in RF energy harvesting in the design of reconfigurable harvesting elements.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Compact-Size Low-Profile Wideband Circularly Polarized Omnidirectional Patch Antenna With Reconfigurable Polarizations

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    A compact-size low-profile wideband circularly polarized (CP) omnidirectional antenna with reconfigurable polarizations is presented in this communication. This design is based on a low-profile omnidirectional CP antenna which consists of a vertically polarized microstrip patch antenna working in TM01/TM02 modes and sequentially bended slots etched on the ground plane for radiating horizontally polarized electric field. The combined radiation from both the microstrip patch and the slots leads to a CP omnidirectional radiation pattern. The polarization reconfigurability is realized by introducing PIN diodes on the slots. By electronically controlling the states of the PIN diodes, the effective orientation of the slots on ground plane can be changed dynamically and the polarization of antenna can be altered between left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP). The proposed antenna exhibits a wide-operational bandwidth of 19.8% (2.09-2.55 GHz) with both axial ratio below 3 dB and return loss above 10 dB when radiates either LHCP or RHCP waves. Experimental results show good agreement with the simulation results. The present design has a compact size, a thickness of only 0.024? and exhibits stable CP omnidirectional conical-beam radiation patterns within the entire operating frequency band with good circular polarization

    Reconfigurable Wideband Circularly Polarized Microstrip Patch Antenna for Wireless Applications

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    In this thesis, developments of rectangular microstrip patch antenna to have circular polarization agility with wideband performance, for wireless applications are presented. First, a new technique to achieve circularly polarized (CP) probe feed single-layer microstrip patch antenna with wideband characteristics is proposed. The antenna is a modified form of the popular E-shaped patch, used to broaden the impedance bandwidth of a basic rectangular patch antenna. This is established by letting the two parallel slots of the E-patch unequal. Thus, by introducing asymmetry two orthogonal currents on the patch are excited and circularly polarized fields are realized. The proposed technique exhibits the advantage of the simplicity inherent in the E-shaped patch design. It requires only slot lengths, widths, and position parameters to be determined. Also, it is suitable for later adding the reconfigurable capability. With the aid of full-wave simulator Ansoft HFSS, investigations on the effect of various dimensions of the antenna have been carried out via parametric analysis. Based on these investigations, a design procedure for a CP E-shaped patch is summarized. Various design examples with different substrate thicknesses and material types are presented and compared, with CP U-slot patch antennas, recently proposed in the literature. A prototype has been constructed following the suggested design procedure to cover the IEEE 802.11b/g WLAN band. The performance of the fabricated antenna was measured and compared with the simulation results for the reflection coefficient, axial ratio, radiation pattern, and antenna gain. Good agreement is achieved between simulation and measured results demonstrating a high gain and wideband performance. Second, a polarization reconfigurable single feed E-shaped patch antenna with wideband performance is proposed. The antenna is capable of switching from right-hand circular polarization (RHCP) to left-hand circular polarization (LHCP) and vice versa, with the aid of two RF PIN diodes that act as RF switches. The proposed structure which is simple; consists of a single-layer single fed radiating E-shaped patch and RF switch placed on each of its slots at an appropriate location. The design targets WLAN IEEE 802.11b/g frequency band (2.4- 2.5 GHz) as one example of the wireless applications. The idea is based on the first proposed design. In other words, if one of the switches is ON and the other is OFF, the two slot lengths will become effectively unequal and circular polarization will be obtained. If the states of the two switches are reversed, circular polarization with opposite orientation will be obtained at the same frequency band. Full-wave simulator Ansoft HFSS is again used for the analysis. Complete detailed DC biasing circuit of the switches for integration with the antenna is presented. Also, characterizations of the microwave components used in the biasing circuit are discussed. Antenna prototype has been fabricated and tested. Simulation results along with the measured one, for the reflection coefficient, axial ratio, radiation pattern, and antenna gain agree well, showing wide bandwidth and high gain for the two circularly polarized modes

    Parasitic Layer-Based Reconfigurable Antenna and Array For Wireless Applications

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    Antenna is one of the most important components in wireless systems since signal transmission and reception are conducted through the antenna interface. Therefore, the signal quality is highly affected by the properties of the antenna. Traditional antennas integrated in devices such as laptops or cell phones have fixed radiation properties and can not be changed to adapt to different environments. Thus the performance of thefwhole system will be negatively affected since the antenna will not operate in the optimum status in different environments. To solve this problem, reconfigurable antenna, which can dynamically change its operation frequency, radiation pattern, and polarization, has gained a significant interest recently. Recongurable antennas are considered smart antennas, and can maximize the capacity of the wireless system. This dissertation focuses upon the theoretical analysis and design of smart antennas with recongurable radiation properties. The presented multi-functional reconfigurable antennas (MRAs) are aimed to applications in WLAN (wireless local area network) systems. The theoretical analysis of the MRA was rst investigated to validate the design concept, and then applied for practical applications. The multi-functional recongurable antenna array (MRAA), which is a new class of antenna array, is also created as a linear formation (4 1) of MRA, with theoretical analysis and design of the MRAA fully described. This work developed three MRA(A)s for practical implementation in WLAN systems. The rst design is the MRA operating in 802.11 b/g band (2.4-2.5 GHz), with nine beam steering directions in a parasitic layer-based MRA structure. The second is a MRA operating in 802.11ac band (5.17-5.83 GHz) with three beam steering directions in a simplied parasitic layer-based MRA structure. The third is a MRAA extension of the second design. The design process of these MRA(A)s is realized with the joint utilization of electromagnetic (EM) full-wave analysis and multi-objective genetic algorithm. All three MRA(A) designs have been fabricated and measured. The measured and simulated results agree well for both impedance and radiation characteristics. These prototypes can be directly employed in a WLAN system since practical limits have been taken into account with real switches and components implemented. Finally, this dissertation work concludes with plans for future work, which will focus on development of MRA(A)s with dual-frequency operation

    Study and Implementation of Wideband Bow-Tie Antennas

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    Demand for multifunctional electronic devices is increasing in modern wireless communication systems. As the antenna plays a vital role in wireless communication, the need to design antennas which will provide better performance and more reliable communication is growing. In this thesis, innovative designs for antennas with wideband characteristic have been proposed to meet the demands of current multi-functional wireless communication systems. First, this thesis explores the design of a wideband pattern reconfigurable antenna with steady realized gain over the operating bandwidth. Another novel design of this thesis work is a highly directive wideband Yagi antenna. Finally, a two-planar structured CPLPDA antenna is designed to overcome the currently existing three-planar structured CPLPDA antenna’s complex design and fabrication process

    A Software Controlled Polarization and Pattern Reconfigurable Microstrip Parasitic Array Antenna for a Market Mediated Software Defined Communications System

    Get PDF
    Software Defined Radio (SDR) provides a platform for a reconfigurable communication system that is solely controlled by a software program with access to certain hardware modules. SDRs are typically connected to very minimalistic, and often, manually controlled reconfigurable antenna(s) with no software control over radiation parameters. Hence, on a wave propagation front, the radiator does not capitalize on the software infrastructure it is connected to. This thesis presents a software controlled pattern and polarization reconfigurable microstrip patch antenna, with reconfigurable parasitic elements, for reconfigurable wireless networks and applications. The antenna is designed to operate from 2.4 GHz to 2.5 GHz, covering all channels (channels 1 through 14) of the 2.4 GHz ISM band. This broadband behavior is achieved with a two-layer stacked annular ring patch antenna, separated by a layer of foam. This antenna is dual probe-fed to achieve vertical and horizontal linear polarizations as well as right-hand and left-hand circular polarizations. Pattern reconfiguration is achieved with a third layer composed of microstrip patch elements acting as parasitic radiators, either reflecting or directing a beam in a direction, which are controlled by RF PIN diodes. Elements are placed such that pattern reconfiguration is possible across all polarization modes. Various iterations of the design process are discussed along with their issues and solutions. Other reconfiguration techniques are also suggested as part of future work
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