Multiband Antenna System Research Articles

A multi-band MIMO antenna system with coupled-fed modified rectangular patch elements for 5G systems

A four-port multiple input multiple output (MIMO) antenna system constructed of four compact dual-band (38/60 GHz) microstrip patch antennas is proposed for 5G mobile applications. Each individual element is optimized to achieve the desired performance of the overall MIMO system. Numerical and experimental investigations are achieved to assess the performance of both the single-element antenna and the four-port MIMO antenna system. It is shown that the simulation results agree with the experimental measurements, and both show good performance of the proposed MIMO antenna system. The bandwidths achieved around 38 GHz and 60 GHz are about 2 GHz and 3.2 GHz, respectively. The performance of the MIMO antenna system including the return loss at each antenna port and the coupling coefficients between the different ports are investigated. The radiation patterns produced when each port is excited alone are shown to be suitable for spatial diversity scheme. They have a high radiation efficiency exhibited by a balloon-like shaped radiation pattern for both the upper and lower frequency bands. It is shown that the envelope correlation coefficient (ECC) and the diversity gain (DG) are suitable for performance for the targeted 5G bands.

A Dual Ka/Q-Band Reflectarray

Introduction. Duplex satellite communication is commonly arranged using two spaced frequency bands, with one band receiving and the other band transmitting signals to a satellite. The main task of a communications satellite antenna system consists in providing an identical coverage area across all involved frequency bands, which is often a challenging task for conventional parabolic reflector antennas. Reflectarrays allow an independent control of the reradiated wave phase in spaced frequency bands, which can be used to create efficient multi-band antenna systems for modern communication satellites.Aim. To develop a Ka/Q-frequency range phase-correcting element and to create on its basis a dual-band reflectarray for operation with orthogonal circular polarizations and identical gains in a given sector of angles in significantly spaced frequency ranges.Materials and methods. Numerical studies were carried out using the finite element analysis method. Radiation patterns were measured using the near field scanning method.Results. A single-layer dual-band phase-correcting reflectarray element was developed for operation with orthogonal circular polarizations with low losses and a weak dependence of the relative position of the elements on the phase characteristic. On the basis of the proposed element, a reflectarray consisting of 24 465 two-frequency elements was synthesized and manufactured. The developed prototype of a single-layer dual-band reflectarray demonstrated good characteristics, with the efficiency reaching 56 and 36 % in the Ka- and Q-frequency ranges, respectively, and an almost identical minimum gain in the ±0.75° angle sector.Conclusion. The research results confirm the potential of the developed reflectarray to successfully replace conventional parabolic reflectors installed both on modern communication satellites and as part of ground-based satellite terminals in the millimeter wavelength range.

Reconfigurable a Dual-Port Multi-Band Antenna System with High Isolation Tuning Characteristics for Portable Wireless Devices

Reconfigurable a Dual-Port Multi-Band Antenna System with High Isolation Tuning Characteristics for Portable Wireless Devices

A novel multi-band and multi-generation (2G, 3G,4G, and 5G) 9-elements MIMO antenna system for 5G smartphone applications

A novel multi-band and multi-generation (2G, 3G,4G, and 5G) 9-elements MIMO antenna system for 5G smartphone applications

A compact triband miniaturized MIMO antenna for WLAN applications

This paper proposes a four-port, four-element multi-band Multiple-Input Multiple-Output (MIMO) antenna array that resonates at 2.4 GHz, 2.9 GHz, and/or 5.8 GHz frequency bands for WLAN applications. A Complementary Split Ring Resonator (CSRR) was designed on the ground plane of the FR4 substrate with a rectangular patch antenna on the top plane for antenna size miniaturization, bandwidth improvement, compactness, and isolation enhancement. At first, the presence of the CSRR on the conventional antenna creates additional frequency bands and reduces the frequency of the conventional patch antenna from 24.2 GHz to 5.8 GHz. Even though the CSRR as radiating elements are closer to each other at λ/4 in the MIMO design, minimum isolation is achieved by limiting the unnecessary surface current flow that exists between the elements of the antenna. Consequently, an orthogonal method of the antenna element is adopted for the four-port MIMO antenna system with high port-to-port measured isolation of less than −19 dB, −18 dB, and –22 dB for 2.4 GHz, 2.9 GHz, and 5.8 GHz frequency bands respectively. Antenna size reduction of 96.87%, 95.41%, and 81.10% and gain of 3.94 dBi, 3.80 dBi, and 4.08 dBi were achieved for the miniaturized multi-band antenna operating at 2.4 GHz, 2.9 GHz, and 5.8 GHz frequency bands, respectively. The results also provided overall good diversity performances with the ECC < 0.01, DG > 9.98, MEG < 3 dB, and TARC in all of the proposed multi-band MIMO antenna systems at respective frequencies. The reflection & transmission coefficients, surface currents, radiation patterns, total efficiency, and diversity parameters are presented and discussed. Moreover, the proposed integration of CSRR with the antenna for MIMO antenna arrays has the advantage of multi-band operation, size reduction, isolation enhancement, good diversity, and high gain performances. With this, it is possible to conclude that the proposed metamaterial multi-band MIMO antenna is the right candidate for WLAN applications.

Reconfigurable Multiband Operation for Wireless Devices Embedding Antenna Boosters

Wireless devices such as smart meters, trackers, and sensors need connections at multiple frequency bands with low power consumption, thus requiring multiband and efficient antenna systems. At the same time, antennas should be small to easily fit in the scarce space existing in wireless devices. Small, multiband, and efficient operation is addressed here with non-resonant antenna elements, featuring volumes less than 90 mm3 for operating at 698–960 MHz as well as some bands in a higher frequency range of 1710–2690 MHz. These antenna elements are called antenna boosters, since they excite currents on the ground plane of the wireless device and do not rely on shaping complex geometric shapes to obtain multiband behavior, but rather the design of a multiband matching network. This design approach results in a simpler, easier, and faster method than creating a new antenna for every device. Since multiband operation is achieved through a matching network, frequency bands can be configured and optimized with a reconfigurable matching network. Two kinds of reconfigurable multiband architectures with antenna boosters are presented. The first one includes a digitally tunable capacitor, and the second one includes radiofrequency switches. The results show that antenna boosters with reconfigurable architectures feature multiband behavior with very small sizes, compared with other prior-art techniques.

ШИРОКОСМУГОВІ АНТЕНИ НА ОСНОВІ КІЛЬЦЕВОЇ ГЕОМЕТРІЇ

В роботі розглянуто варіанти моделей квазіфрактальних кільцевих структур. Для їх синтезу запропонований векторний опис фрактальної трансформації окремих сегментів початкової геометричної форми. Поєднання декомпозиції геометричної форми та багатовимірного фрактального підходу дозволяє спростити синтез фрактальних 3D-структур та/або використовувати кілька видів фракталів, у тому числі, з різною кількістю ітерацій. Такий підхід дозволяє досягти широкосмуговості та багатодіапазонності антенних систем. При цьому досліджено вплив рівня сегментації та варіантів схеми живлення на просторово-частотні характеристики антени. Через складність опису взаємодії антен неевклідової геометрії з радіохвилями для їх синтезу та аналізу обрано методи чисельного моделювання. Для аналізу просторово-частотних характеристик проектованих антенних рішень використані такі показники, як зворотні втрати, діаграма спрямованості та коефіцієнт стоячої хвилі. Отримані оцінки відносної смуги пропускання δf = 0,9 свідчать про перспективність запропонованого підходу для реалізації антенних систем з високим рівнем широкосмуговості

Multi-Band and High Gain Antenna Using AMC Ground Characterized With Four Zero-Phases of Reflection Coefficient

In this paper, a multi-band AMC-backed antenna system characterized with high gain and low-profile is proposed. It is constructed by placing a quad-band coplanar-waveguide (CPW) antenna over an AMC with four zero-phases in the reflection coefficient. The CPW antenna consists of an ornamental-pillar-shaped patch with the specially designed parasitic elements, and a defected ground structure (DGS), for the application in the frequency bands of 2.45, 3.5, 4.6 and 5.8 GHz. To improve the CPW antenna’s radiation performance, an artificial magnetic conductor (AMC) ground with four zero-phases of the reflection coefficient is designed and employed as the reflector. The AMC unit cell is composed of four metallic nested rings (FMNR), whose innermost ring is connected in series to four lumped capacitors. It is observed that the proposed quad-band AMC ground can not only increase the gains of the multi-band antenna greatly but also combine the two intermediate frequency bands of the antenna into a broadband one. The prototypes of the antenna and the AMC array with $5\times {5}$ unit cells were fabricated and measured. It is found that in comparison to the antenna without AMC, the AMC-backed antenna obtains a gain enhancement by amounts of 4.93, 5.92, 5.54 and 4.95 dB at the frequencies of 2.45, 3.5, 4.6 and 5.8 GHz. The 10-dB impedance bandwidths of the AMC-backed antenna include three bands of 2.13–2.87, 3.22–4.75, and 5.54–5.86 GHz, with the corresponding relative bandwidths of 14.8%, 38.4%, and 5.3%. The proposed antenna can be potentially applied to the applications in WLAN, WiMAX, and 5G mobile communication systems.

Design of Multiband Antenna Systems for Wireless Devices Using Antenna Boosters [Application Notes

Antennas play a significant role in the current everythingconnected era. From smartphones, to smart meters, to Internet of Things (IoT) devices, every wireless device needs at least one antenna to transmit and receive information. In response, the wireless industry is moving fast to launch new devices into this growing market. This is pushing RF/microwave and wireless engineers to design RF chains in a smart way using off-the-shelf components, such as filters, amplifiers, diplexers, and front-end modules. At the end of this RF chain, an antenna is needed to efficiently transmit/receive electromagnetic waves. Accordingly, an off-the-shelf antenna component would be an attractive option for simplifying the entire design processâ not only the antenna-design phase but also the device-manufacturing process, reducing costs and creating compatibility with pick-and-place machines for mass production.

Quasi‐fractal antenna system based on asymmetric TEM‐horns nested into each other

AbstractIn this article was studied a way to minimize the overall dimensions of a multiband antenna system operating in a number of ultra‐wideband frequency bands using the quasi‐fractal construction principle. The results of an experimental study of the designed antenna element, which is a set of asymmetrical self‐similar TEM‐rupors nested into each other, are presented.

Frequency-Dependent Directive Radiation of Monopole-Dielectric Resonator Antenna Using a Conformal Frequency Selective Surface

Development of a conformal frequency selective surface (FSS) for radiation diversity of hybrid monopole-dielectric resonator antenna has been demonstrated in this paper. In the proposed method, a planar FSS screen with meandered unit cell is designed to be reflective at 5 GHz followed by its mapping on a cylindrical surface of flexible dielectric material. The proposed conformal reflector when kept at a specific distance from the radiating element improves the bandwidth of the antenna from 26.8% to 53.67% in 4–6 GHz band. A significant enhancement of 5–6 dBi in gain is also achieved over this band. Gain of the antenna with reflector is maintained around 9.5 dBi with a variation of ±1.5 dB. On the other hand, omni-directional radiation of the antenna is maintained at an upper band of 7–9 GHz. Simulations have been performed using ANSYS High Frequency Structure Simulator (HFSS). Experimental measurements of the fabricated prototype have been provided. The proposed design is useful to achieve pattern diversity in multiband antenna system.

Wideband turnstile junction coaxial waveguide orthomode transducer

A wideband turnstile junction coaxial waveguide orthomode transducer (OMT) is presented in this paper, featuring coaxial waveguide input and orthogonal rectangular waveguide outputs. It primarily comprises of a turnstile junction, bending stepped impedance transformers and power combiners. The symmetrical geometry helps achieve wide operating bandwidth and balanced output phases. The OMT covers the whole Ku band from 12 to 18 GHz, which aims at wideband dual-polarized signal combination and separation within coaxial-type multi-band antenna systems. An experimental prototype is manufactured and the measured results confirm that the reflection coefficient is lower than −15 dB within the whole band, and the port isolation is better than 35 dB. Turnstile junction coaxial waveguide OMTs can be adopted widely in circular/coaxial waveguide hybrid feeding networks for multi-band satellite communication/remote sensing antenna systems.

Wideband, Multiband, Tunable, and Smart Antenna Systems for Mobile and UWB Wireless Applications 2016

Wideband, Multiband, Tunable, and Smart Antenna Systems for Mobile and UWB Wireless Applications 2016

A Multiband Multiple-input Multiple-output Antenna System for Long Term Evolution and Wireless Local Area Networks Handsets

A novel multiband multiple-input-multiple-output (MIMO) antenna system is proposed. The MIMO antenna system consists of two antenna elements, each of which comprises of three radiators: a driven monopole, an S-shaped strip and an inverted F-shaped strip and occupies footprint of 15x18.5x0.8 mm3 only. The driven monopole acts as a quarter-wave monopole and stimulate higher mode resonance. The two strips are excited by electromagnetic coupling from the driven monopole and serve as two additional monopoles leading to a wideband performance for the lower band. The bandwidths (VSWR ≤ 2.75) achieved for the antenna element are 1.67 – 2.2 GHz for the lower band and 2.28 –2.95 GHz for the upper band which cover LTE-1, LTE- 2, LTE- 3, LTE- 7, LTE- 40 and WLAN 2.4 GHz bands. A T-shaped slot and another two slots are introduced to reduce the coupling effect between the two multiband antenna elements. The isolation achieved is higher than 18 dB over the whole band, leading to an envelope correlation coefficient of less than 0.01. Furthermore, the diversity characteristics of mean effective gains (MEGs) and diversity gain (DG) are also studied. Both the simulated and measured results are shown to illustrate the performance of the proposed multiband MIMO antenna system, and that confirms the suitability for LTE and WLAN handset applications.

Wideband, Multiband, Tunable, and Smart Antenna Systems for Mobile and UWB Wireless Applications 2014

Wideband, Multiband, Tunable, and Smart Antenna Systems for Mobile and UWB Wireless Applications 2014

4 × 4 MIMO Multiband Antenna System for Mobile Handsets

A 4 × 4 MIMO multiband antenna system for mobile handsets is proposed in this paper. The placement of the elements on the terminal chassis as well as the single structure has been optimized in order to reduce the Envelope Correlation Coefficient (ECC). Simulated and measured results, including also the integration with a a real 7-inch commercial tablet, aimed at validating the proposed solution are presented.

MIMO multiband antenna system with nonresonant elements

ABSTRACTMulti‐input multi‐output (MIMO) technology will enable high‐data rates in wireless devices to allow speech and video calls to streaming media and web browsing all over a common platform. MIMO technology needs M antennas both in transmission and reception. As the space in a wireless device is limited, including M antennas is a challenge. To face such challenge, a MIMO antenna system is proposed which comprises two small nonresonant elements operating in the frequency region 824–960 MHz and two identical elements operating at 1710–2170 MHz. The size of each of the nonresonant elements is only 5 × 5 × 5 mm3. The proposed MIMO system is analyzed in terms of bandwidth, efficiency, correlation, and multiplexing efficiency. MIMO capacity is measured in a reverberation chamber considering a free‐space Rayleigh scenario and also including the effect of a phantom head and hand. The results reveal that the proposed MIMO system provides capacity close to the ideal bound while having a small size and able to operate at several 2G, 3G, and 4G long term evolution standards. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:183–190, 2015

A Planar Dipole for Multiband Antenna Systems With Self-Balanced Impedance

In this letter, we present a multiframe L-slot planar dipole loaded with a single microstripline for multiband antenna systems. The multiband is achieved by creating a multiframe L-slot on a host dipole and also by loading the host dipole antenna with a single microstripline to generate a couple of shunts and series of capacitive gaps with an inductive strip, eventually forming LC-like resonators. The antenna supports several wireless communication bands including: LTE bands at 1.7 ~ 1.8 and 2.3 ~ 2.6 GHz; WLAN bands at 2.4 ~ 2.5, 5.2, and 5.8 GHz; WiBro/WiMAX bands at 3 ~ 4 GHz. In addition, to validate the multiband behaviors, we also proposed a simple equivalent circuit for the designed antenna in which biconical transmission lines were adopted to model the host dipole sections. The simulation, fabrication, and measurement of the proposed antenna were implemented. As a result, its reflection coefficients |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | were found to be better than -7 dB for most operating frequencies along with a sufficiently large bandwidth and good radiation patterns.

Printed Multi-Band MIMO Antenna Systems and Their Performance Metrics [Wireless Corner

Multiple-input-multiple-output (MIMO) antenna systems are a key enabling technology for modern fourth-generation (4G) wireless systems. The need for higher data rates for multimedia applications within the limited bandwidth and power levels led the way to the use of multiple antennas at the receiver and transmitter ends. Printed MIMO antenna systems, supporting multiple bands, including the lower band of the 4G wireless standard (LTE), pose a challenge in terms of available size. In this work, we start by defining the new required metrics to characterize MIMO antenna systems. We then present several recent printed multi-band MIMO antenna systems, along with some isolation-enhancement mechanisms that are used in these closely packed antennas.

Multiband and Small Coplanar Antenna System for Wireless Handheld Devices

Multiband and small antennas are strongly demanded in current wireless handheld or portable devices that require multiband operation. Nowadays, trends are focused on exciting ground plane radiation modes in order to reduce as much as possible the volume devoted to the antenna element. This paper studies different geometries for determining which one better excites a ground plane radiation mode at different frequency regions. The results demonstrate that a non-resonant pad element attains the best tradeoff between performance and geometry complexity. A multiband antenna system featuring small coplanar pad elements is proposed for providing operation at the communication standards LTE700 (698-787 MHz), GSM850 (824-894 MHz), GSM900 (880-960 MHz), GSM1800 (1710-1880 MHz), GSM1900 (1850-1990 MHz), UMTS (1920-2170 MHz), LTE2100 (1920-2170 MHz), LTE2300 (2300-2400 MHz), LTE2500 (2500-2690 MHz) as well as at the satellite positioning systems GPS (1575 MHz), Galileo L1 (1559-1591 MHz), Glonass (1592-1609 MHz). A radiofrequency system comprising broadband matching networks is included to provide the required impedance bandwidth. Numerical results give physical insight into the behavior of the proposed planar element. A prototype is built to demonstrate the feasibility of the proposal. The proposed radiating system is appealing for the new wireless handheld devices due to its small size (153 ), planar profile, and multiband performance.