685 research outputs found

    Wideband and UWB antennas for wireless applications. A comprehensive review

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    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

    A design of reconfigurable filtering-antenna for ultra-wideband applications

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    Antenna is a main element in the UWB systems to transmit and receive signals. However, there are challenges to meet the requirements for a suitable UWB antenna compare to other narrowband antennas such as high data rate, omnidirectional radiation pattern and wide frequency bandwidth. Since the UWB technology is facing the interference problem with other narrow band signals such as WiMAX, WLAN and HiperLAN, which severely degrade the performance of the receiver in the UWB system, thus the conventional UWB system is integrated with bandstop filter in separated model from the antenna, which leads to increase complexity, cost, weight and loss. Therefore, researchers tend to integrate resonant structure in the antenna design to produce band notch characteristics and filter out unwanted signals using different techniques such as defected ground structure (DGS), defected patch structure (DPS) and resonant structure beside the feedline of the antenna design. However, the disadvantages of these techniques are the excessive band rejection, which rejects needed frequencies, and the fixed band notch whether the interfering signal exists or not, which may reduce the performance of the UWB system, thus producing sufficient and switchable band notch is a challenging issue to improve the performance of the UWB system. Therefore, in this research, a modified monopole antenna is designed to produce UWB bandwidth using microstrip transition in the feedline and block with triangular slot on each side of the circular patch. The modified monopole antenna is integrated with resonant structures to produce band notch characteristics and filter out unwanted signals. Two techniques based on defected microstrip structure (DMS) and two double split ring resonator (DSRR) are integrated with the antenna design individually. The DMS is embedded in the feedline of the antenna design to produce single band notch. The two DSRR are loaded above the ground plane of the antenna design to produce dual band notches. A PIN diode is employed in the resonant structure to achieve frequency reconfiguration. The results show that the modified monopole antenna exhibits wide bandwidth (129.5%) with a return loss better than -15 dB, high frequency skirt selectivity ranging from 3 to 14 GHz, which covers the entire UWB frequency band (3.1-10.6 GHz), peak gain of 5.3 dB and omnidirectional radiation pattern. The new integrations of filtering-antenna using DMS and DSRR provide stable omnidirectional azimuth pattern and sharp band notches, which are sufficient to remove unwanted signals and keep wanted signals. The simulated and measured results show a good agreement, where the proposed filtering-antenna using DMS exhibits wide bandwidth with switchable band notch at 5.5 GHz (WLAN), and the filtering-antenna using two DSRR exhibits wide bandwidth with switchable sharp band notches at 3.5 GHz (WiMAX) and 5.55 GHz (HiperLAN2)

    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

    Fast design optimization of UWB antenna with WLAN Band-Notch

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    In this paper, a methodology for rapid design optimization of an ultra-wideband ( UWB) monopole antenna with a lower WLAN band-notch is presented. The band-notch is realized using an open loop resonator implemented in the radiation patch of the antenna. Design optimization is a two stage process, with the first stage focused on the design of the antenna itself, and the second stage aiming at identification of the appropriate dimensions of the resonator with the purpose of allocating the band-notch in the desired frequency range. Both optimization stages are realized using surrogate-based optimization involving variable-fidelity electromagnetic ( EM) simulation models as well as an additive response correction ( first stage), and sequential approximate optimization ( second stage). The final antenna design is obtained at the CPU cost corresponding to only 23 high-fidelity EM antenna simulations

    Dielectric Resonator Antennas: Applications and developments in multiple-input, multiple-output technology

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    This article presents a comprehensive review of multiple-input, multiple-output (MIMO) dielectric resonator antennas (DRAs) that have evolved in the past decade. In addition to the major challenges faced during designing an MIMO DRA, this article also discusses research gaps that must be filled in the future. Exploring the advantages of DRAs, numerous novel designs have been proposed in the last few years

    Slotted Printed Monopole UWB Antennas with Tuneable Rejection Bands for WLAN/WiMAX and X-Band Coexistence

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    YesFour versions of the compact hexagonal-shaped monopole printed antennas for UWB applications are presented. The first proposed antenna has an impedance bandwidth of 127.48 % (3.1 GHz to 14 GHz), which satisfies the bandwidth for ultra-wideband communication systems. To reduce the foreseen co-channel interference with WLAN (5.2GHz) and X-Band systems (10GHz), the second and third antennas type were generated by embedding hexagonal slot on the top of the radiating patch. The integration of the half and full hexagonal slots created notched bands that potentially filtered out the sources of interference, but were static in nature. Therefore, a fourth antenna type with tuneable-notched bands was designed by adding a varactor diode at an appropriate location within the slot. The fourth antenna type is a dual-notch that was electronically and simultaneously tuned from 3.2GHz to 5.1GHz and from 7.25GHz up to 9.9GHz by varying the bias voltages across the varactor. The prototypes of the four antenna versions were successfully fabricated and tested. The measured results have good agreement with the simulated results.This work is carried out under the grant of the FundacĂŁo para a CiĂŞncia e a Tecnologia (FCT - Portugal), with the reference number: SFRH / BPD / 95110 / 201

    Design a new notched UWB antenna to rejected unwonted band for wireless communication

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    This paper presents a slotted design for ultra-wideband (UWB) antenna. Design of a rectangular UWB antenna covering the frequency range 3.1-10.6 GHz, to achieve notch characteristics in the bands at 3.1-8.4 GHz and 8.6-10.6 GHz. By changing the direction of distribution of current to apply this technique by inserting three C-shaped holes and two pairs of rectangular notches below the antenna. The simulation results reveal that the proposed structure is in good accord with the simulation results. The proposed UWB antenna size is (100x90x1.6 mm)3. This proposed design could provide a solution to eliminating bands that interfere in a UWB band depending on the aperture design. The simulated findings reveal that the UWB antenna operates in the 8.5 GHz center frequency range and rejects all frequency bands utilizing slits. This antenna design can provide a solution to remove UWB bands from 3.1-10.6 except for 8.5 GHz which only works. By using the notch, we got a large increase in the gain. makes to be a suitable candidate for X-band-UWB applications

    Filtering antenna with two-octave harmonic suppression

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    A novel 2nd–order antenna with filtering performance and two-octave harmonic suppression is proposed. In order to reduce the effects of the harmonics of the antenna, two types of antennas (PIFA and patch) with different resonant characteristics are integrated into the design. Compared with the traditional patch antennas, this integrated work can not only eliminate the high-order harmonics of the antenna but also improve the in-band bandwidth and frequency selectivity. The 2nd and 4th–order harmonics of the patch are suppressed because of the detuned harmonic performance of the PIFA and patch. The 3rd-order harmonic is eliminated by integrating notch resonators in the PIFA. A prototype works at 2.4 GHz is developed to demonstrate the PIFA-patch integration scheme. Measured and simulated results of antennas agree well with each other, demonstrating good performance of bandwidth, 2nd-order filtering, radiation and wideband harmonic suppression (up to 11 GHz)

    A planar UWB semicircular-shaped monopole antenna with quadruple band notch for WiMAX, ARN, WLAN, and X-Band

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    This paper proposed quadruple notched frequency bands ultra-wideband (UWB) antenna. The antenna is a semicircular-shaped monopole type of a compact size 36x24 mm, covering frequency range of 3.02-14 GHz. Four rejected narrow bands including WiMAX (3.3-3.7GHz), ARN (4.2-4.5 GHz), WLAN (5.15-5.825GHz), X-Band (7.25-7.75) have been achieved using inserting slots techniques in the patch, feed line, and ground plane. The slots dimensions have been optimized for the required reject bands. The antenna design and analysis have been investigated by simulation study using CST-EM software package. The antenna characteristics including impedance bandwidth, surface current, gain, radiation efficiency, radiation pattern have been discussed

    Reconfigurable and multi-functional antennas

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    This thesis describes a research into multi-frequency and filtering antennas. Several novel antennas are presented, each of which addresses a specific issue for future communication systems, in terms of multi-frequency operation, and filtering capability. These antennas seem to be good candidates for implementation in future multiband radios, cognitive radio (CR), and software defined radio (SDR). The filtering antenna provides an additional filtering action which greatly improves the noise performance and reduces the need for filtering circuitry in the RF front end. Two types of frequency reconfigurable antennas are presented. One is tunable left-handed loop over ground plane and the second is slot-fed reconfigurable patch. The operating frequency of the left handed loop is reconfigured by loading varactor diodes whilst the frequency agility in the patch is achieved by inserting switches in the coupling slot. The length of the slot is altered by activating the switches. Compact microstrip antennas with filtering capabilities are presented in this thesis. Two filtering antennas are presented. Whilst the first one consists of three edge-coupled patches, the second filtering antenna consists of rectangular patch coupled to two hairpin resonators. The proposed antennas combine radiating and filtering functions by providing good out of band gain suppression
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