2,792 research outputs found

    Design and Analysis of Frequency Reconfigurable Micro strip Antennas

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    The goal of this thesis is to design and analyse the frequency reconfigurable microstrip patch antenna which are mainly the combination of filters and antennas called filtering antennas (filtennas). The increasing demand for high data rate and new wireless communication has led to the development of multifunctional devices including antennas and radio frequency (RF) front ends. The novel solution is to design antennas which has multiband, multimode, low profile, low cost and easy to integrate with portable devices. In this thesis three different frequency reconfigurable microstrip patch antenna has been proposed for cognitive radio system. The design and simulation of the proposed antennas are d one in CST (computer simulation technology) microwave simulation software. The first design is single port frequency agile antenna for overlay cognitive radio. When all the PIN diodes are in ON state, it is UWB and used to sense the entire spectrum and by selectively changing the PIN diode states five different reconfigurable cases occurs which is used for communication. Thereflection coefficient curve of UWB antenna shows bandwidth from 3.1 GHz to 9.8 GHz and reconfigurable antenna resonate at 6.7 GHz, 5.33 Hz, 5.73 GHz, 7.04 GHz, 6.33 GHz and 9.45 GHz. The second antenna proposed is dual port microstrip patch for cognitive radio system. This design is used for overlay cognitive radio in which one antenna is for sensing and other for communication. Sensing and communication can be done simultaneously and tuning in reconfigurable antenna can be done continuously. UWB antenna bandwidth is from 3.4 GHz to 13.2 GHz and the reconfigurable antenna is dual and triple band resonating frequency according to the biasing of varactor. The radiation pattern obtained in both cases are almost omnidirectional which is good for mobile application and sensing antenna. The third design is proposed for underlay cognitive radio system in which UWB antenna is used which radiate at very low power. The UWB antenna resonates from 2.8 GHz to 13.4 GHz. The filter is then added to this antenna as notch reconfigurable and this can be used to communicate over long distance without interference with primary used. The notches depends on states of PIN diodes, the frequency which are rejected are 5 GHz, 5.7 GHz, 6.45 GHz, 7.5 GHz, 9 GHz. The fourth proposed design is planar inverted F antenna (PIFA) for mobile devices. Currently cellular phones are using more than one services, so many antennas are needed. In the proposed design two varactor diodes has been used for tuning of operating frequency so that one antenna can replace many antennas for different wireless services like WIFI, WIMAX, GPS,WLAN , WiBro etc. .The simulated refection coefficient of this antenna shows dual band and triple band from 2 GHz to 5.5 GHz at different varactor diode biasing states

    Reconfigurable wideband patch antenna for cognitive radio

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    Cognitive radio communication is envisaged to be a new paradigm of methodologies for enhancing the performance of radio communication systems through the efficient utilization of radio spectrum. A key enabler for realization of a cognitive communication system is the capability of re-configurability in the underlying hardware and the associated protocol suite. Reconfigurable double C-Slot microstrip patch antenna fed by 50 ohm microstrip line is proposed in this paper. The frequency tuning is performed by switching on and off two patches. The antenna can operate in dual-band or in very wide band mode in 5, 6 and 7 GHz bands. The wide-band mode can be obtained when both switches are in the ON state with impedance bandwidth of 33.52 % from 4.99 to 7 GHz. The total size of the ground plane is 50 x 50 mm2. The proposed antenna verified through both numerical simulation and measurement of an experimental prototype. The antenna achieves a gain of 5 to 8 dBi and radiation efficiency about 80%

    A reconfigurable dual port antenna system for underlay/interweave cognitive radio

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    An antenna system that is reconfigurable in frequency is presented in this paper as a novel dual port design that serves both undelay and interweave cognitive radio. This 25×40×0.8 mm3 system is composed of two wide slot antennas: the first is designed as an ultra-wideband (UWB) antenna with controllable band rejection capabilities, while the second antenna is reconfigurable for communication purposes. Three slots are etched into the patch of the UWB antenna to obtain band notching in wireless local area network/Xband/International Telecommunication Union bands (WLAN/Xband/ITU) bands which can be controlled by a positive-intrinsic-negative (PIN) diode across each slot. The configuration states of these three diodes are all useable that produces seven band rejection modes plus the UWB operation mode. The second antenna is configured by five PIN diodes to operate either in Cband, WLAN or Xband regions which results in three interweave modes when setting the first antenna for UWB sensing. The design is simulated by computer simulation technology (CST) v.10. S21 results shows good isolation while input reflection coefficient and realized gain results prove system’s scanning, filtering and communication capabilities. This system is new that it gathers the undelay/interweave operation in a single design and when considering its large number of operation modes it looks adequate for many cognitive radio applications

    Reconfigurable dual band microstrip patch antenna for software defined radio applications

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    In this paper, a reconfigurable microstrip patch antenna with RF pin diode switches is implemented for dual band of 2.4 GHz and 5.6 GHz Software Defined Radio (SDR) applications. For the dual band SDR system, the use of a single antenna with a wide bandwidth to cover both of the bands can be limiting for low power level signal applications due to wideband noise. A reconfigurable nested microstrip patch antenna is designed on a Rogers 5880 RT/DUROID substrate which is fed by a coaxial probe from the back side of the grounded substrate. RF switching circuitry involves four RF pin diodes at each side of the inner patch. The dual bands of 2.4 GHz and 5.6 GHz frequency operation can be simply obtained by switching the PIN diodes on and off. The antenna is well matched and achieves approximately 7 dBi simulated gain at both frequency bands. Simulation results show that the nested patch antenna is suitable for dual band SDR applications

    A reconfigurable wideband and multiband antenna using dual-patch elements for compact wireless devices

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    This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 IEEEA reconfigurable wideband and multiband C-Slot patch antenna with dual-patch elements is proposed and studied. It occupies a compact volume of 50 × 50 × 1.57 (3925 mm3), including the ground plane. The antenna can operate in two dual-band modes and a wideband mode from 5 to 7 GHz. Two parallel C-Slots on the patch elements are employed to perturb the surface current paths for excitation of the dual-band and the wideband modes. Two switches, implemented using PIN diodes, are placed on the connecting lines of a simple feed network to the patch elements. Dual-band modes are achieved by switching “ON” either one of the two patch elements, while the wideband mode with an impedance bandwidth of 33.52% is obtained by switching “ON” both patch elements. The frequencies in the dual-band modes can be independently controlled using positions and dimensions of the C-Slots without affecting the wideband mode. The advantage of the proposed antenna is that two dual-band operations and one wideband operation can be achieved using the same dimensions. This overcomes the need for increasing the surface area normally incurred when designing wideband patch antennas. Simulation results are validated experimentally through prototypes. The measured radiation patterns and peak gains show stable responses and are in good agreements. Coupling between the two patch elements plays a major role for achieving the wide bandwidth and the effects of mutual coupling between the patch elements are also studied

    A Frequency-Reconfigurable Monopole Antenna with Switchable Stubbed Ground Structure

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    A frequency-reconfigurable coplanar-waveguide (CPW) fed monopole antenna using switchable stubbed ground structure is presented. Four PIN diodes are employed in the stubs stretching from the ground to make the antenna reconfigurable in three operating modes: a single-band mode (2.4-2.9 GHz), a dual-band mode (2.4-2.9 GHz/5.09-5.47 GHz) and a triple-band mode (3.7-4.26 GHz/5.3-6.3 GHz/8.0-8.8 GHz). The monopole antenna is resonating at 2.4 GHz, while the stubs produce other operating frequency bands covering a number of wireless communication systems, including WLAN, WiMAX, C-band, and ITU. Furthermore, an optimized biasing network has been integrated into this antenna, which has little influence on the performance of the antenna. This paper presents, compares and discusses the simulated and measured results

    Single-, Dual- and Triple-band Frequency Reconfigurable Antenna

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    The paper presents a frequency reconfigurable slot dipole antenna. The antenna is capable of being switched between single-band, dual-band or triple-band operation. The antenna incorporates three pairs of pin-diodes which are located within the dipole arms. The antenna was designed to operate at 2.4 GHz, 3.5 GHz and 5.2 GHz using the aid of CST Microwave Studio. The average measured gains are 1.54, 2.92 and 1.89 dBi for low, mid and high band respectively. A prototype was then constructed in order to verify the performance of the device. A good level of agreement was observed between simulation and measurement

    Compact printed multiband antenna with independent setting suitable for fixed and reconfigurable wireless communication systems

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    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.This paper presents the design of a low-profile compact printed antenna for fixed frequency and reconfigurable frequency bands. The antenna consists of a main patch, four sub-patches, and a ground plane to generate five frequency bands, at 0.92, 1.73, 1.98, 2.4, and 2.9 GHz, for different wireless systems. For the fixed-frequency design, the five individual frequency bands can be adjusted and set independently over the wide ranges of 18.78%, 22.75%, 4.51%, 11%, and 8.21%, respectively, using just one parameter of the antenna. By putting a varactor (diode) at each of the sub-patch inputs, four of the frequency bands can be controlled independently over wide ranges and the antenna has a reconfigurable design. The tunability ranges for the four bands of 0.92, 1.73, 1.98, and 2.9 GHz are 23.5%, 10.30%, 13.5%, and 3%, respectively. The fixed and reconfigurable designs are studied using computer simulation. For verification of simulation results, the two designs are fabricated and the prototypes are measured. The results show a good agreement between simulated and measured results
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