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

Realizing uwb antenna array with dual and wide rejection bands using metamaterial and electromagnetic bandgaps techniques

This research article describes a technique for realizing wideband dual notched functionality in an ultra-wideband (UWB) antenna array based on metamaterial and electromagnetic bandgap (EBG) techniques. For comparison purposes, a reference antenna array was initially designed comprising hexagonal patches that are interconnected to each other. The array was fabricated on standard FR-4 substrate with thickness of 0.8 mm. The reference antenna exhibited an average gain of 1.5 dBi across 5.25-10.1 GHz. To improve the array's impedance bandwidth for application in UWB systems metamaterial (MTM) characteristics were applied it. This involved embedding hexagonal slots in patch and shorting the patch to the ground-plane with metallic via. This essentially transformed the antenna to a composite right/left-handed structure that behaved like series left-handed capacitance and shunt left-handed inductance. The proposed MTM antenna array now operated over a much wider frequency range (2-12 GHz) with average gain of 5 dBi. Notched band functionality was incorporated in the proposed array to eliminate unwanted interference signals from other wireless communications systems that coexist inside the UWB spectrum. This was achieved by introducing electromagnetic bandgap in the array by etching circular slots on the ground-plane that are aligned underneath each patch and interconnecting microstrip-line in the array. The proposed techniques had no effect on the dimensions of the antenna array (20 mm x 20 mm x 0.87 mm). The results presented confirm dual-band rejection at the wireless local area network (WLAN) band (5.15-5.825 GHz) and X-band satellite downlink communication band (7.10-7.76 GHz). Compared to other dual notched band designs previously published the footprint of the proposed technique is smaller and its rejection notches completely cover the bandwidth of interfering signals

Slot Antennas - A Comprehensive Survey

Wireless Communication has found a rapid growth over the past decades starting from handheld devices to spacecraft applications. The efficient operation of all such wireless devices depends on the design and proper working of the transmitting and receiving antennas. Microstrip antennas are most commonly preferred for major wireless applications, because of their miniaturized structure, ease of fabrication, low power consumption, flexibility with printed circuit board, low profile, light weight, effective return loss and better radiation properties. This paper provides a comprehensive survey on microstrip antennas whose performance is improved to meet the increasing demand, by introducing slots of different shapes and sizes. These slots of various kinds helps in obtaining wider bandwidth over the C and Ultrawideban

A four-element UWB MIMO antenna using SRRs for application in satellite communications

This paper proposes a method for designing a new ultra wide band (UWB) multiple-input multiple-output (MIMO) antenna with two and four elements. First we presented an ultra-wide band antenna we studied these performances. Then, we studied the application of metamaterials to the design of MIMO antennas for miniaturization and the performance of antennas, in order to guarantee the proper functioning of the MIMO system with a much reduced separation distance between the radiating elements (λ/12), where the coupling can be very weak. The application of these circular double ring SRRs materials on the front plan of the antenna has contributed to the increasing of the antenna performance is studied in terms of S-Parameters, efficiency, diversity gain (DG), radiation properties and envelop correlation coefficient (ECC). It offers advantages such as the reduction of weight and congestion that is beneficial for their integration into satellite communications systems

Perancangan Antena Coplanar Vivaldi Menggunakan Metamaterial Dan Corrugated Slot Pada Frekuensi Ultra-Wideband (UWB)

Teknologi telekomunikasi wireless merupakan bidang yang memegang peranan penting dalam kehidupan manusia. Antena merupakan front end dari sistem teknologi wireless yang merupakan komponen utama dalam pengiriman dan penerimaan data. Penelitian ini membahas perancangan Antena Coplanar Vivaldi dengan menggunakan Metamaterial dan Corrugated Slot yang bekerja pada rentang frekuensi UWB yaitu 3,1 GHz hingga 10,6 GHz. Pada penelitian ini dibandingkan kinerja empat macam antena yaitu antena Coplanar Vivaldi (antena Model-A), antena Coplanar Vivaldi dengan penambahan Corrugated Slot (antena Model-B), antena Coplanar Vivaldi dengan penambahan Metamaterial Superstrate dan Corrugated Slot (antena Model-C) serta antena Coplanar Vivaldi dengan penambahan Metamaterial CSRR dan Corrugated Slot (antena Model-D). Metamaterial adalah struktur elektromagnetik yang memiliki karakteristik permeabilitas dan permitivitas negatif. Dengan adanya penambahan struktur metamaterial pada bagian substrat dan corrugated slot pada kedua sisi antena diperoleh nilai kinerja return loss terendah yaitu antena Model-C sebesar -43 dB pada frekuensi 7,1 GHz dan terjadi peningkatan gain sebesar 1,63 dB dibandingkan antena Model-A pada frekuensi 5 GHz. Penambahan struktur metamaterial pada antena coplanar vivaldi memiliki beberapa kelebihan jika dibandingkan dengan antena lainnya, dikarenakan menghasilkan gain yang lebih tinggi di frekuensi rendah. Kata kunci: Antena Coplanar Vivaldi, Metamaterial, Corrugated Slot, Ultra-Wideband (UWB)

Miniaturized Microwave Devices and Antennas for Wearable, Implantable and Wireless Applications

This thesis presents a number of microwave devices and antennas that maintain high operational efficiency and are compact in size at the same time. One goal of this thesis is to address several miniaturization challenges of antennas and microwave components by using the theoretical principles of metamaterials, Metasurface coupling resonators and stacked radiators, in combination with the elementary antenna and transmission line theory. While innovating novel solutions, standards and specifications of next generation wireless and bio-medical applications were considered to ensure advancement in the respective scientific fields. Compact reconfigurable phase-shifter and a microwave cross-over based on negative-refractive-index transmission-line (NRI-TL) materialist unit cells is presented. A Metasurface based wearable sensor architecture is proposed, containing an electromagnetic band-gap (EBG) structure backed monopole antenna for off-body communication and a fork shaped antenna for efficient radiation towards the human body. A fully parametrized solution for an implantable antenna is proposed using metallic coated stacked substrate layers. Challenges and possible solutions for off-body, on-body, through-body and across-body communication have been investigated with an aid of computationally extensive simulations and experimental verification. Next, miniaturization and implementation of a UWB antenna along with an analytical model to predict the resonance is presented. Lastly, several miniaturized rectifiers designed specifically for efficient wireless power transfer are proposed, experimentally verified, and discussed. The study answered several research questions of applied electromagnetic in the field of bio-medicine and wireless communication.Comment: A thesis submitted for the degree of Ph

ULTRA-WIDEBAND MICROSTRIP ANTENNA ENHANCED PERFORMANCE USING METAMATERIAL

Antenna engineering is very important in the development of communication systems and the requirements for low profile antennas that cover a wide spectrum of frequencies increase the number of researches in this field. Accordingly, scientists have focused on UWB microstrip antennas that cover the range from 3.1 GHz to 10.6 GHz but others concentrate on enhancing its performance using a special type of materials called metamaterials. The main objective of this work is to enhance frequency bandwidth, antenna gain, and radiation pattern for the UWB circular microstrip antenna by employing the Split Ring Resonator (SRR) technique, which is one type of metamaterial. Circular and square split-ring resonators are investigated as an enhancement method after studying their characteristics. Multiple techniques are also applied to these two structures prior to being implemented at the antenna’s backside including different SRR schematics such as the SRR position with respect to the ground, inner and outer ring rotation, positive and negative rotation angle, number of SRR units, SRR size, SRR design, in addition to using the complementary SRR. Furthermore, two techniques are combined together in some designs to observe how the antenna’s performance will be affected. The proposed techniques rely on the variation in capacitance and inductance which will affect the resonant frequency of the SRR unit cell. Then some SRR Schematics were implemented in the proposed circular antenna design to test the functionality within WiFi frequencies 2.4 GHz and 5 GHz. The enhancement can be summarized in increasing antenna bandwidth and transmitting or rejecting specific frequency bands. The results of the study reveal an enhancement in circular antenna performance. UWB circular antenna with elliptical rings has a frequency bandwidth between 3.5 GHz to 9 GHz and a maximum gain of around 5 dB; during the enhancement process using the previously mentioned techniques, the frequency bandwidth increased to cover the range from 2.2 GHz to 9.8 GHz along with some bands rejection. It was noted that some rejected bands have shifted to higher frequencies when applying inner or outer ring rotation. To emphasize this, WiFi frequencies 2.4 GHz and 5GHz are inspected by using the suitable size of S-SRR to decide which frequency to reject or transmit depending on the communication applications. The outcomes of this work should assist in designing antennas with SRR depending on required communication applications and operating frequencies

Miniature Planar Antenna Design for Ultra-Wideband Systems

Demand for antennas that are compact and operate over an ultra‐wideband (UWB) frequency range is growing rapidly as UWB systems offer high resolution imaging capability and high data rate transmission in the order of Gb/s that is required by the next generation of wireless communication systems. Hence, over the recent years the research and development of UWB antennas has been widely reported in literature. The main performance requirements sought from such antennas include: (1) low VSWR of <2; (2) operation over 7.6 GHz from 3 to 10.6 GHz; and (3) good overall radiation characteristics. Significant size reduction and low manufacturing cost are also important criteria in order to realize a cost‐effective and miniature system. Other desirable requirements include compatibility and ease of integration with RF electronics

Through Wall Imaging Radar Antenna with a Focus on Opening New Research Avenues

This review paper is an effort to develop insight into the development in antennas for through wall imaging radar application. Review on literature on antennas for use in through wall imaging radar, fulfilling one or more requirements/specifications such as ultrawide bandwidth, stable and high gain, stable unidirectional radiation pattern, wide scanning angle, compactness ensuring portability and facilitating real-time efficient and simple imaging is presented. The review covers variants of Vivaldi, Bow tie, Horn, Spiral, Patch and Magneto-electric dipole antennas demonstrated as suitable antennas for the through wall imaging radar application. With an aim to open new research avenues for making better through wall imaging radar antenna, review on relevant compressive reflector antennas, surface integrated waveguide antennas, plasma antennas, metamaterial antennas and single frequency dynamically configurable meta-surface antennas are incorporated. The review paper brings out possibilities of designing an optimum through wall imaging radar antenna and prospects of future research on the antenna to improve radiation pattern and facilitate overall simple and efficient imaging by the through wall imaging radar

Wide Band Embedded Slot Antennas for Biomedical, Harsh Environment, and Rescue Applications

For many designers, embedded antenna design is a very challenging task when designing embedded systems. Designing Antennas to given set of specifications is typically tailored to efficiently radiate the energy to free space with a certain radiation pattern and operating frequency range, but its design becomes even harder when embedded in multi-layer environment, being conformal to a surface, or matched to a wide range of loads (environments). In an effort to clarify the design process, we took a closer look at the key considerations for designing an embedded antenna. The design could be geared towards wireless/mobile platforms, wearable antennas, or body area network. Our group at UT has been involved in developing portable and embedded systems for multi-band operation for cell phones or laptops. The design of these antennas addressed single band/narrowband to multiband/wideband operation and provided over 7 bands within the cellular bands (850 MHz to 2 GHz). Typically the challenge is: many applications require ultra wide band operation, or operate at low frequency. Low frequency operation is very challenging if size is a constraint, and there is a need for demonstrating positive antenna gain