Showing papers on "Antenna array published in 2019"
12 May 2019
TL;DR: A novel channel estimation protocol for PIS-assisted energy transfer (PET) from a multiantenna power beacon (PB) to a single-antenna energy harvesting (EH) user is presented.
Abstract: Usage of passive intelligent surface (PIS) is emerging as a low-cost green alternative to massive antenna systems for realizing high energy beamforming (EB) gains. To maximize its realistic utility, we present a novel channel estimation (CE) protocol for PIS-assisted energy transfer (PET) from a multiantenna power beacon (PB) to a single-antenna energy harvesting (EH) user. Noting the practical limitations of PIS and EH user, all computations are carried out at PB having required active components and radio resources. Using these estimates, near-optimal analytical active and passive EB designs are respectively derived for PB and PIS, that enable efficient PET over a longer duration of coherence block. Nontrivial design insights on relative significance of array size at PIS and PB are also provided. Numerical results validating theoretical claims against the existing benchmarks demonstrate that with sufficient passive elements at PIS, we can achieve desired EB gain with reduced active array size at PB.
497 citations
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TL;DR: Simulation results reveal that deploying large-scale IRSs in wireless systems is more efficient than increasing the antenna array size at the AP for enhancing both the spectral and the energy efficiency.
Abstract: Intelligent reflecting surfaces (IRSs) have received considerable attention from the wireless communications research community recently. In particular, as low-cost passive devices, IRSs enable the control of the wireless propagation environment, which is not possible in conventional wireless networks. To take full advantage of such IRS-assisted communication systems, both the beamformer at the access point (AP) and the phase shifts at the IRS need to be optimally designed. However, thus far, the optimal design is not well understood. In this paper, a point-to-point IRS-assisted multiple-input single-output (MISO) communication system is investigated. The beamformer at the AP and the IRS phase shifts are jointly optimized to maximize the spectral efficiency. Two efficient algorithms exploiting fixed point iteration and manifold optimization techniques, respectively, are developed for solving the resulting non-convex optimization problem. The proposed algorithms not only achieve a higher spectral efficiency but also lead to a lower computational complexity than the state-of-the-art approach. Simulation results reveal that deploying large-scale IRSs in wireless systems is more efficient than increasing the antenna array size at the AP for enhancing both the spectral and the energy efficiency.
309 citations
TL;DR: A novel user pairing scheme is developed so that more than two users can be grouped in a cluster to exploit the NOMA technique and an iterative penalty function-based beamforming scheme is presented to obtain the BF weight vectors and power coefficients with fast convergence.
Abstract: In this paper, we propose a joint optimization design for a non-orthogonal multiple access (NOMA)-based satellite-terrestrial integrated network (STIN), where a satellite multicast communication network shares the millimeter wave spectrum with a cellular network employing NOMA technology. By assuming that the satellite uses multibeam antenna array and the base station employs uniform planar array, we first formulate a constrained optimization problem to maximize the sum rate of the STIN while satisfying the constraint of per-antenna transmit power and quality-of-service requirements of both satellite and cellular users. Since the formulated optimization problem is NP-hard and mathematically intractable, we develop a novel user pairing scheme so that more than two users can be grouped in a cluster to exploit the NOMA technique. Based on the user clustering, we further propose to transform the non-convex problem into an equivalent convex one, and present an iterative penalty function-based beamforming (BF) scheme to obtain the BF weight vectors and power coefficients with fast convergence. Simulation results confirm the effectiveness and superiority of the proposed approach in comparison with the existing works.
273 citations
TL;DR: A new technique for communication information embedding into the emission of multiple-input multiple-output (MIMO) radar using sparse antenna array configurations, which shows that by reconfiguring sparse transmit array through antenna selection and reordering waveform-antenna pairing, a data rate of megabits per second can be achieved for a moderate number of transmit antennas.
Abstract: Spectrum congestion and competition over frequency bandwidth could be alleviated by deploying dual-function radar-communications systems, where the radar platform presents itself as a system of opportunity to secondary communication functions. In this paper, we propose a new technique for communication information embedding into the emission of multiple-input multiple-output (MIMO) radar using sparse antenna array configurations. The phases induced by antenna displacements in a sensor array are unique, which makes array configuration feasible for symbol embedding. We also exploit the fact that in a MIMO radar system, the association of independent waveforms with the transmit antennas can change over different pulse repetition periods without impacting the radar functionality. We show that by reconfiguring sparse transmit array through antenna selection and reordering waveform-antenna pairing, a data rate of megabits per second can be achieved for a moderate number of transmit antennas. To counteract practical implementation issues, we propose a regularized antenna-selection-based signaling scheme. The possible data rate is analyzed and the symbol/bit error rates are derived. Simulation examples are provided for performance evaluations and to demonstrate the effectiveness of proposed dual-function radar-communication techniques.
147 citations
TL;DR: In this article, a dual-band dual-polarized base station antenna array is developed for 5G applications by introducing a frequency-selective surface (FSS) between radiators operating in the 0.69-0.96 GHz and 3.5-4.9 GHz bands.
Abstract: A dual-band dual-polarized base station antenna array is developed for fifth generation (5G) applications. Low-profile characteristic, high isolations, and shared-aperture are realized by introducing a frequency-selective surface (FSS) between radiators operating in the 0.69–0.96 GHz (B1) and 3.5–4.9 GHz (B2) bands. The dual-polarized B1-band antenna has a low-profile height of $0.12~\lambda _{L}$ ( $\lambda _{L}$ is the wavelength at the center frequency of B1). As for the B2 band, a $2 \times 2$ dual-polarized array sharing the same aperture with the B1-band antenna is developed for the sub-6 GHz band. Severe mutual coupling between B1- and B2-band antennas is reduced by the FSS. High port isolation (> 25 dB) between B1- and B2-band antennas is achieved. A prototype consisting of one B1-band antenna and a $2 \times 2$ B2-band antenna array is fabricated. Measured results show that the proposed dual-band dual-polarized array achieves 32.7% and 33.3% bandwidth in the B1 and B2 bands, respectively. Measured results also demonstrate that the proposed array offers stable radiation patterns, high gains, and high cross-polarization discriminations (XPD > 20 dB) across the two frequency bands. These attractive features make this array an ideal candidate for future 5G massive MIMO base station antenna developments.
137 citations
TL;DR: The proposed dual-band eight-antenna array for multiple-input and multiple-output (MIMO) applications in 5G mobile terminals can maintain acceptable radiation and MIMO performance in the presence of specific anthropomorphic mannequin head and human hands.
Abstract: This paper proposes a dual-band eight-antenna array for multiple-input and multiple-output (MIMO) applications in 5G mobile terminals. The designed MIMO antenna array comprises eight L-shaped slot antennas based on stepped impedance resonators (SIRs). The required dual-resonance can be obtained by adjusting the impedance ratio of the SIR, and good impedance matching can be ensured for each antenna element by tuning the position of the microstrip feed line. The experimental results show that a measured return loss of higher than 10 dB and a measured inter-element isolation of greater than 11.2 dB have been obtained for each antenna element with a simulated total efficiency of larger than 51% across the long term evolution (LTE) band 42 (3400-3600 MHz) and LTE band 46 (5150-5925 MHz). In addition, the measured envelope correlation coefficient (ECC) is lower than 0.1 between arbitrary two antenna elements, and the proposed MIMO antenna array realizes a simulated channel capacity of higher than 36.9 bps/Hz within both operation bands. Furthermore, the MIMO antenna array can maintain acceptable radiation and MIMO performance in the presence of specific anthropomorphic mannequin (SAM) head and human hands.
127 citations
TL;DR: In this paper, a closely located dual-band meander-line antenna array with isolation enhancement by inserting novel split electromagnetic bandgap (EBG) uniplanar structure is proposed.
Abstract: A closely located dual-band meander-line antenna array with isolation enhancement by inserting novel split electromagnetic bandgap (EBG) uniplanar structure is proposed. The meander-line antenna is coupled to a parasitic rectangular patch to achieve the dual-band operation. Splits are applied on the surface of an EBG structure to cause decoupling at the first resonant mode and utilizing an EBG structure to decouple at the second resonant mode. The prototype of the proposed structure achieves a dual band of 180 MHz (3.42–3.6 GHz) and 400 MHz (4.7–5.1 GHz). The mutual coupling is significantly reduced by 26 and 44 dB at 3.48 and 4.88 GHz, respectively, compared to the reference antenna. In addition, the structure has high front-to-back ratio radiation characteristics.
120 citations
TL;DR: In this article, the authors considered a general multipair mMIMO relaying system with a mixed-ADC/DAC architecture, in which some antennas are connected to low-resolution ADCs and DACs, while the rest of the antennas were connected to high-resolution ADC/DCs.
Abstract: High power consumption and expensive hardware are two bottlenecks for practical massive multiple-input multiple-output (mMIMO) systems. One promising solution is to employ low-resolution analog-to-digital converters (ADCs) and digital-to-analog converters (DACs). In this paper, we consider a general multipair mMIMO relaying system with a mixed-ADC/DAC architecture, in which some antennas are connected to low-resolution ADCs/DACs, while the rest of the antennas are connected to high-resolution ADCs/DACs. Leveraging on the additive quantization noise model, both exact and approximate closed-form expressions for the achievable rate are derived. It is shown that the achievable rate can approach the unquantized one by using only 2–3 bits of resolutions. Moreover, a power scaling law is presented to reveal that the transmit power can be scaled down inversely proportional to the number of antennas at the relay. We further propose an efficient power allocation scheme by solving a complementary geometric programming problem. In addition, a tradeoff between the achievable rate and power consumption for different numbers of low-resolution ADCs/DACs is investigated by deriving the energy efficiency. Our results reveal that the large antenna array can be exploited to enable the mixed-ADC/DAC architecture, which significantly reduces the power consumption and hardware cost for practical mMIMO systems.
117 citations
TL;DR: The imaging results indicate the possibility of using the designed conformal array to detect a bleeding inside the brain using a confocal image algorithm.
Abstract: Given the increased interest in a fast, portable, and on-spot medical diagnostic tool that enables early diagnosis for patients with brain stroke, a new approach of a wearable electromagnetic head imaging system based on the polymer material is proposed. A flexible low-profile, wideband, and unidirectional antenna array with electromagnetic band gap (EBG) and metamaterial (MTM) unit cells reflector is utilized. The designed antenna consists of a 4 × 4 radiating patch loaded with symmetrical extended open-ended U-slots and fed by combination of series and corporate transmission lines. A mushroom-like 10-EBG unit cell arrays are arranged around the feeding network to reduce surface waves, whereas 4 × 4 MTM unit cells are placed on the back-side of the antenna to enable unidirectional radiation. The antenna is designed and embedded on a multilayer low cost, low loss, transparent, and robust polymer poly-di-methyl-siloxane (PDMS) substrate and optimized to operate in contact with the human head. The simulated and measured results show that the antenna has a fractional bandwidth of 53.8% (1.16–1.94 GHz), more than 80% of radiation efficiency, and satisfactory field penetration in the head tissues with a safe specific absorption rate. An eight-element array is then configured on 300 × 360 × 4.1 mm3 PDMS material covering an average human head size and used as a worn part of the imaging system. A realistic-shaped 3-D specific anthropomorphic mannequin (SAM) head phantom is used to verify the performance of the designed array. The imaging results indicate the possibility of using the designed conformal array to detect a bleeding inside the brain using a confocal image algorithm.
105 citations
TL;DR: The novelty of this paper is the collocation of a high- frequencies end-fire 5G antenna array with an old-generation low-frequency antenna, such as 4G in small space in the mobile terminal, without interfering with the radiation pattern and impedance matching of both low- and high-frequency antennas.
Abstract: In this paper, a novel technique of collocating a millimeter-wave end-fire 5G beam steerable array antenna with a low-frequency planar inverted-F antenna (PIFA) is presented. In this technique, the low-frequency antenna can be transparent by using some grating strips between the low- and high-frequency antennas. A quad-element mm-wave array with end-fire radiation patterns operating in 22–31 GHz is integrated with a dual-band low-frequency PIFA in a mobile terminal. The novelty of this paper is the collocation of a high-frequency end-fire 5G antenna array with an old-generation low-frequency antenna, such as 4G in small space in the mobile terminal, without interfering with the radiation pattern and impedance matching of both low- and high-frequency antennas. The proposed 5G antenna covers 22–31 GHz and can scan ±50° with the scan loss of better than 3 dB. The coverage efficiency of the proposed mm-wave 5G antenna is better than 50% and 80% for a minimum gain of 4 and 0 dBi in 22–31 GHz, respectively. The gain of the high-frequency antenna array is better than 9.5 dBi at 28 GHz. The low-frequency antenna covers some practical 4G LTE bands from 740–960 MHz and 1.7–2.2 GHz bands. The measured results in both low and high frequencies agree well with the simulations.
104 citations
TL;DR: The proposed MIMO antenna array in a smartphone with an open-slot metal frame for fifth-generation (5G) communications is presented, with high agreement between the measured and simulated results, which means that the proposed antenna is promising in engineering application.
Abstract: A design of an ultra-wideband eight-port multiple-input multiple-output (MIMO) antenna array in a smartphone with an open-slot metal frame for fifth-generation (5G) communications is presented. Each element is fed by a microstrip line with a tuning stub, consisting of a U-slot on the ground plane and an open slot on the metal frame. Each slot element on the ground only occupies an area of 15 x3 mm. The antenna array can operate in 3.3-6 GHz (S
11
<; -6 dB) that is ultra-wide bandwidth for the future 5G communications. The antenna array is manufactured and measured. Measured antenna isolation is higher than 11 dB without any decoupling structures applied. Moreover, measured radiation patterns, antenna efficiencies, and envelop correlation coefficients are also given in this paper. High agreement between the measured and simulated results is obtained, which means that the proposed antenna is promising in engineering application.
TL;DR: In this article, the authors proposed an efficient downlink channel reconstruction scheme for a frequency-division-duplex multi-antenna system by utilizing uplink channel state information combined with limited feedback.
Abstract: In this paper, we propose an efficient downlink channel reconstruction scheme for a frequency-division-duplex multi-antenna system by utilizing uplink channel state information combined with limited feedback. Based on the spatial reciprocity in a wireless channel, the downlink channel is reconstructed by using frequency-independent parameters. First, we estimate the gains, delays, and angles during uplink sounding. The gains are then refined through downlink training and sent back to the base station (BS). With limited overhead, the refinement can substantially improve the accuracy of the downlink channel reconstruction. The BS can then reconstruct the downlink channel with the uplink-estimated delays and angles and the downlink-refined gains. We also introduce and extend the Newtonized orthogonal matching pursuit (NOMP) algorithm to detect the delays and gains in a multi-antenna multi-subcarrier condition. The results of our analysis show that the extended NOMP algorithm achieves high-estimation accuracy. The simulations and over-the-air tests are performed to assess the performance of the efficient downlink channel reconstruction scheme. The results show that the reconstructed channel is close to the practical channel and that the accuracy is enhanced when the number of BS antennas increases, thereby highlighting the promising application of the proposed scheme in large-scale antenna array systems.
TL;DR: This paper focuses on the evolution and development of mm-wave array antenna and its implementation for wireless communication and numerous other related areas and the new design aspects and research directions are unfolded.
Abstract: The enormous growth of wireless data traffic in recent years has made the millimeter-wave (mm-wave) technology as a good fit for high-speed communication systems. Extensive works are continuing from the device to system, to the radio architecture, to the network to support the communication in mm-wave frequency ranges. To support this extensive high data rate, beam forming is found to be the key-enabling technology. Hence, an array antenna design is an extremely important issue. The beam-forming arrays are chosen to achieve the desired link capacity considering the high path loss and atmospheric loss at mm-wave frequencies and also to increase the coverage of the mm-wave communication system. There are diverse design challenges of the array due to the small size, use of large numbers of antennas in close vicinity, integration with radio-frequency (RF) front ends, hardware constraints, and so on. This paper focuses on the evolution and development of mm-wave array antenna and its implementation for wireless communication and numerous other related areas. The scope of the discussion is extended on the reported works in every sphere of mm-wave antenna array design, including the selection of antenna elements, array configurations, feed mechanism, integration with front-end circuitry to understand the effects on system performance, and the underlying reason of it. The new design aspects and research directions are unfolded as a result of this discussion.
TL;DR: Simulation results show that the proposed approach can significantly reduce the service time to ground users compared with a fixed-array case in which the same number of drones form a fixed uniform antenna array.
Abstract: In this paper, the effective use of multiple quadrotor drones as an aerial antenna array that provides wireless service to ground users is investigated. In particular, under the goal of minimizing the airborne service time needed for communicating with ground users, a novel framework for deploying and operating a drone-based antenna array system whose elements are single-antenna drones is proposed. In the considered model, the service time is minimized by minimizing the wireless transmission time as well as the control time that is needed for movement and stabilization of the drones. To minimize the transmission time, first, the antenna array gain is maximized by optimizing the drone spacing within the array. In this case, using perturbation techniques, the drone spacing optimization problem is addressed by solving successive, perturbed convex optimization problems. Then, according to the location of each ground user, the optimal locations of the drones around the array’s center are derived such that the transmission time for the user is minimized. Given the determined optimal locations of drones, the drones must spend a control time to adjust their positions dynamically so as to serve multiple users. To minimize this control time of the quadrotor drones, the speed of rotors is optimally adjusted based on both the destinations of the drones and external forces (e.g., wind and gravity). In particular, using bang–bang control theory, the optimal rotors’ speeds as well as the minimum control time are derived in closed-form. Simulation results show that the proposed approach can significantly reduce the service time to ground users compared with a fixed-array case in which the same number of drones form a fixed uniform antenna array. The results also show that, in comparison with the fixed-array case, the network’s spectral efficiency can be improved by 32% while leveraging the drone antenna array system. Finally, the results reveal an inherent tradeoff between the control time and transmission time while varying the number of drones in the array.
TL;DR: In this article, a flexible mmWave antenna array for 5G wireless networks operating at Ka-band (26.5-40 GHz) was proposed, which is comprised of a coplanar-waveguide-fed rectangular patch tapered at its sides with two vertically oriented slots.
Abstract: This letter presents the design, fabrication, and performance evaluation of a flexible millimeter-wave (mm-wave) antenna array for the fifth generation (5G) wireless networks operating at Ka -band (26.5–40 GHz). The single element antenna is comprised of a coplanar-waveguide-fed rectangular patch tapered at its sides with two vertically oriented slots. The ground is designed with L-shaped stubs to converge the dispersed radiation pattern for improving the directivity and gain. The antenna fabrication is accomplished by two advanced methods of laser-milling and inkjet printing on a thin film of flexible liquid crystal polymer. A novel and time-efficient method for postprinting sintering is also proposed in this letter. The design is extended in a two-element array for the gain enhancement. Measurements have validated that the proposed antenna array exhibits a bandwidth of 26–40 GHz with a peak gain of 11.35 dBi at 35 GHz, and consistent high gain profile of above 9 dBi in the complete Ka -band. These features recommend the proposed antenna array as an efficient solution for integration in future flexible 5G front ends and mm-wave wearable devices.
TL;DR: In this paper, a closely coupled dual-band multiple-input-multiple-output (MIMO) patch antenna that resonates at 3.7 and 4.1 GHz was presented.
Abstract: This letter presents a closely coupled dual-band multiple-input–multiple-output (MIMO) patch antenna that resonates at 3.7 and 4.1 GHz. The MIMO antenna is composed of two mirror-symmetrical single-feed patch antennas that are closely placed with approximately 0.034 λ0 (where λ0 is the wavelength at 3.7 GHz). The decoupling structure consists of the modified array antenna decoupling surface (MADS) and H-shaped defect ground structures for the lower band and upper band, respectively. Through simulation and measurement, the isolation is determined to be greater than 30 dB in both frequency bands, showing a noticeable improvement compared to the original antenna array. Under the effect of the MADS, the measured gain increases by 2.2 and 0.8 dB at the resonance frequencies of 3.7 and 4.1 GHz, respectively. The measured results indicate that the proposed decoupling structure is quite suitable for closely spaced dual-band MIMO antennas.
TL;DR: In this paper, an efficient T-shaped decoupling network is proposed to decouple closely spaced two-element E-plane antenna array based on network analysis and implementation deduction, which is extended to a three-element one by combining with a fine transmission line and further generalized to a multielement linear one.
Abstract: Strong mutual coupling between both adjacent and nonadjacent elements is unavoidable, especially when antenna array is densely arranged. In this paper, an efficient T-shaped decoupling network is primarily proposed to decouple closely spaced two-element E-plane antenna array based on network analysis and implementation deduction. Subsequently, it is extended to a three-element one by combining with a fine transmission line and further generalized to a multielement linear one. All the accordant simulation and measurement results demonstrate that as compared to the coupled arrays, impedance matching, radiation patterns, and scanning characteristics of the decoupled arrays are evidently improved through adding the decoupling network, while mutual coupling between every two elements is greatly reduced. Moreover, such combined decoupling network is effective in the H-plane array and monopole antenna array, implying its huge potential for large-scale array and various arrays.
TL;DR: This paper considers the standard array manifold models used in signal processing works and shows that they differ, sometimes significantly, from the model based on electromagnetic theory.
Abstract: The problem of locating signals transmitted in the proximity of an antenna array has been studied extensively in the signal processing literature. In this paper, we consider the standard array manifold models used in these works and show that they differ, sometimes significantly, from the model based on electromagnetic theory. In particular, the standard models do not correspond to the equations governing an electromagnetic field near an antenna or an array. They also do not take into account the characteristics of the near-field source, such as the type and orientation of the transmitting antenna, which may have a profound impact on the signals received by the array. We use selected numerical examples based on a numerical electromagnetic code to illustrate the various issues raised herein.
TL;DR: In this paper, a stacked antenna array consisting of a lowerband antenna element working in 690-960 MHz frequency band and four upper-band antenna elements operating in the 3.5-4.9 GHz band is designed to demonstrate the concept.
Abstract: A novel stacked antenna configuration is proposed for the designs of shared-aperture base station antennas. An antenna array consisting of a lower-band antenna element working in 690–960 MHz frequency band and four upper-band antenna elements operating in the 3.5–4.9 GHz band is designed to demonstrate the concept. In the proposed configuration, four upper-band antenna elements are placed over the aperture of the lower-band antenna. Four metallic sheets are introduced to provide capacitive loading for the lower-band antenna and simultaneously offer a ground plane for the upper-band antennas. Therefore, low-profile characteristic and high isolations between the dual-band antennas are guaranteed. The overall height of the antenna array is only $0.17\lambda _{\text {L0}}$ ( $\lambda _{\text {L0}}$ is the free-space wavelength at the center frequency of the lower band), which is much lower than those of conventional designs. The measured results demonstrate that the designed antenna array achieves 32.7% and 33.3% impedance bandwidth in the lower and upper bands, respectively. High port isolations (>30 dB), high gains (>8 dBi), and stable radiation patterns are achieved in the two frequency bands. Owing to its simple structure and compact size, the resultant antenna array is easy for fabrication and is a promising candidate for sub-6 GHz band and 690–960 MHz band antennas.
TL;DR: In this article, a dual-band substrate-integrated waveguide (SIW) antenna array topology is proposed for operation in the 28 and 38 GHz frequency bands, where four miniaturized quartermode SIW cavities are tightly coupled, causing mode bifurcation, and yielding an antenna topology with four distinct resonance frequencies.
Abstract: A novel dual-band substrate-integrated waveguide (SIW) antenna array topology is proposed for operation in the 28 and 38 GHz frequency bands. Four miniaturized quarter-mode SIW cavities are tightly coupled, causing mode bifurcation, and yielding an antenna topology with four distinct resonance frequencies. A pair of resonances is assigned to both the 28 and 38 GHz band, achieving wideband operation in both frequency ranges. Moreover, owing to the exploited miniaturization technique, an extremely compact array topology is obtained, facilitating easy and straightforward integration. The computer-aided design process yields a four-element antenna array that entirely covers the 28 GHz band (27.5–29.5 GHz) and 38 GHz band (37.0–38.6 GHz) with a measured impedance bandwidth of 3.65 and 2.19 GHz, respectively. A measured broadside gain of 10.1 dBi, a radiation efficiency of 75.75% and a 3 dB beamwidth of 25° are achieved in the 28 GHz band. Moreover, in the 38 GHz band, the measured broadside gain amounts to 10.2 dBi, a radiation efficiency of 70.65% is achieved, and the 3 dB beamwidth is 20°.
TL;DR: A systematic design of high performance eight element antenna array for a 5G mobile terminal operating at 2.6/3.5 GHz bands and can be easily implemented for the future smartphones as it utilizes the conductive sheet or chassis and the middle vertically mounted antenna do not use the additional space of the chassis or ground.
Abstract: This work presents a systematic design of high performance eight element antenna array for a 5G mobile terminal operating at 2.6/3.5 GHz bands. The proposed eight element slot antenna array based on unit monopole slot antenna embedded in the metal casing or ground resonates at fundamental mode at 2.6 GHz. The antenna array is developed from four antennas (open-end slot antenna) etched near to the corner edges of the printed circuited board with supported pairs of vertically mounted slot antennas in middle section of the long edge ground plane. This combination of the antenna elements provided pattern diversity and enabled the smartphone in the reception of the signal in a different direction. The impedance bandwidth based on -10 dB return loss criteria cover from 2.4 GHz to 3.6 GHz includes the two allocated bands of (2400 MHz to 2600 MHz) and (3400 MHz to 3600 MHz) for 5G cellular communication systems. The vital MIMO performance measures as envelope correlation coefficient or ECC is less than 0.2 for any two antenna array meeting the required standard of less than 0.5 alongside the mean effective gain or MEG ratio of any two antenna meeting the required standard of less than 3 dB for power balance and optimal diversity performance. As modern smartphone demand desires slim handsets, the after mentioned compact multiple antenna structure can be easily implemented for the future smartphones as it utilizes the conductive sheet or chassis and the middle vertically mounted antenna do not use the additional space of the chassis or ground. The customer hand or human hand effect on the multiple antenna array to mimic the use of mobile phone customer is also studied. The maximum MIMO Channel capacity based on measured result is 34.25bps/Hz and is about 3 times of 2 × 2 MIMO operations.
TL;DR: Meta-surface superstrates are used to decouple two linear polarized antennas coupled in H-plane and E-plane, respectively by properly designing the geometry of the double layer short wires as the unit cell of the meta-surface, as well as the height of theMeta-superstrate.
Abstract: In this paper, meta-surface superstrates are used to decouple two linear polarized antennas coupled in H-plane and E-plane, respectively. By properly designing the geometry of the double layer short wires as the unit cell of the meta-surface, as well as the height of the meta-superstrate, two linearly polarized antennas can be decoupled in H-plane and E-plane, respectively. Both the antenna pairs coupled in E- and H-planes with and without meta-surfaces are fabricated and measured. The results demonstrate that the antennas with the meta-surface superstrate are able to operate in the band of 3.3–3.7 GHz with reflection better than −15 dB and the isolation can be improved from 10 to 25 dB in the H-plane case and can be improved from 15 to 30 dB in the E-plane case. Such decoupling method can be applied extensively in 5G base stations where size constraints are becoming stringent.
TL;DR: This preliminary tutorial introduces the relevant array and transceiver architecture designs proposed in the 3GPP Release 13 that enable elevation beamforming and presents and compares two different 3-D channel modeling approaches that can be utilized for the performance analysis of elevation beamform techniques.
Abstract: Full dimension (FD) multiple-input multiple-output (MIMO) technology has attracted substantial research attention from both wireless industry and academia in the last few years as a promising technique for next-generation wireless communication networks. FD-MIMO scenarios utilize a planar 2-D active antenna system (AAS) that not only allows a large number of antenna elements to be placed within feasible base station (BS) form factors, but also provides the ability of adaptive electronic beam control over both the elevation and the traditional azimuth dimensions. This paper presents a tutorial on elevation beamforming analysis for cellular networks utilizing FD massive MIMO antenna arrays. In contrast to existing works that focus on the standardization of FD-MIMO in the 3rd generation partnership project (3GPP), this tutorial is distinguished by its depth with respect to the theoretical aspects of antenna array and 3-D channel modeling. In an attempt to bridge the gap between industry and academia, this preliminary tutorial introduces the relevant array and transceiver architecture designs proposed in the 3GPP Release 13 that enable elevation beamforming. Then it presents and compares two different 3-D channel modeling approaches that can be utilized for the performance analysis of elevation beamforming techniques. The spatial correlation in FD-MIMO arrays is characterized and compared based on both channel modeling approaches and some insights into the impact of different channel and array parameters on the correlation are drawn. All these aspects are put together to provide a mathematical framework for the design of elevation beamforming schemes in single-cell and multi-cell scenarios. Simulation examples associated with comparisons and discussions are also presented. To this end, this paper highlights the state-of-the-art research and points out future research directions.
TL;DR: The radiation pattern after adding the metasurface superstrate is well maintained with total efficiency improvement by about 10%, and the envelope correlation coefficient between the two antennas is reduced from 0.35 to below 0.12 within the whole band of interest.
Abstract: In this paper, an extremely compact two-element linear polarized multiple-input-multiple-output (MIMO) antenna array with a metasurface superstrate is proposed. Instead of using periodic square split-ring resonators which occupy larger space and which are incident angle variant, double-layer short wire is utilized as the unit cell of the metasurface. The metasurface is compact in size and effective in decoupling two nearby Bowtie antennas strongly coupled in the H-plane with the spacing of only 0.27 wavelength. After decoupling, the isolation between the two antennas has been improved from around 10 dB to more than 25 dB within the band of 2300 to 2690 MHz while their reflection remained below −15 dB. Moreover, the radiation pattern after adding the metasurface superstrate is well maintained with total efficiency improvement by about 10%, and the envelope correlation coefficient between the two antennas is reduced from 0.35 to below 0.12 within the whole band of interest. The proposed method can find plenty of applications in MIMO and 5G communication systems.
TL;DR: In this paper, the authors proposed a dual-band shared-aperture beam-scanning antenna array based on the concept of structure reuse, which consists of four Ku-band linear antenna arrays implemented by the substrate-integrated waveguide (SIW) and four Ka-band antenna arrays.
Abstract: This paper describes the design and realization of a Ku/Ka dual-band shared-aperture beam-scanning antenna array based on the concept of structure reuse. The antenna consists of four Ku-band linear antenna arrays implemented by the substrate-integrated waveguide (SIW) and four Ka-band linear antenna arrays. To increase the aperture utilization efficiency, the Ku-band antenna is employed as some sidewalls of the Ka-band antenna. Thanks to this compact topology, the element spacing at two frequency bands is able to meet the requirement of a wide-angle beam scan. Both feeding networks of these two arrays are designed by proper SIW power dividers through the printed circuit board fabrication process. In addition, the self-filtering characteristic of the antenna, the orthogonal polarization, and the optimal layout of the array are employed to ensure the high channel isolation between the two antennas operating at different frequency bands over the whole beam scan range. The isolation between antennas is better than 28 and 70 dB at the Ku-band and Ka-band, respectively, scanning up to even 40°. The proposed shared-aperture concept and the design results have been validated by the experimental results.
TL;DR: A novel quasi-Yagi antenna is proposed for millimeter-wave (mmWave) 5G cellular handsets operating in the 28 GHz band and designed to be compact through modification of the planar folded dipole topology so that it can be mounted inside a compact mobile terminal.
Abstract: A novel quasi-Yagi antenna is proposed for millimeter-wave (mmWave) 5G cellular handsets operating in the 28 GHz band. The proposed antenna is designed to be compact through modification of the planar folded dipole topology so that it can be mounted inside a compact mobile terminal. A vertically stacked structure utilizing a multilayer printed circuit board (PCB) and via holes is applied to the antenna topology to minimize the antenna lateral width while maintaining the characteristics of the planar folded dipole antenna. A single antenna yields a $-$ 10 dB bandwidth for a return loss of 12.3% (26.3 to 29.75 GHz) and a gain of 5.51 dBi at 28 GHz. The change in beam patterns due to the chassis effect when four-element linear arrays are inserted into the upper and side edge inside the terminal is analyzed.
TL;DR: In this paper, a wideband, low-profile, tightly coupled antenna array with a simple feed network is presented, where dipole and feed networks in each unit cell are printed on both sides of a single RT/Duroid 6010 substrate with a relative dielectric constant of 10.2.
Abstract: A wideband, low-profile, tightly coupled antenna array with a simple feed network is presented. The dipole and feed networks in each unit cell are printed on both sides of a single RT/Duroid 6010 substrate with a relative dielectric constant of 10.2. The feed network, composed of meandered impedance transformer and balun sections, is designed based on Klopfenstein tapered microstrip lines. The wide-angle impedance matching is empowered by a novel wideband metasurface superstrate. For the optimum design, scanning to 70° along the E-plane is obtained together with a very high array figure of merit PA = 2.84. The H-plane scan extends to 55°. The broadside impedance bandwidth is 5.5:1 (0.80–4.38) GHz with an active voltage standing-wave ratio value ≤2. The overall height of the array above the ground plane is $0.088\lambda _{\mathrm {L}}$ , where $\lambda _{\mathrm {L}}$ is the wavelength at the lowest frequency of operation. A prototype was fabricated and tested to confirm the design concepts.
08 Mar 2019
TL;DR: This paper proposes a novel, wireless, and ultra-compact implantable device termed NanoNeuroRFID, which can sense quasi-static neuronal magnetic fields as small as 200 pT without direct contact to the tissue, allowing a long lifetime and reliable neural recording.
Abstract: A major obstacle during the design of brain–computer interfaces is the unavailability of a neural implantable device that is µ-scale in size and is wireless, self-powered, and long-lasting. The current state-of-the-art implantable devices suffer from various limitations. Electromagnetic-based wireless devices are big in size because of their large antenna, which must be larger than one-tenth of the wavelength of the operational frequency. Ultrasound-based wireless devices, in addition to their low data rate, have massive loss in the skull and need an intermediate electromagnetic transceiver under the skull. Furthermore, almost all state-of-the-art wireless devices use micro-electrodes for neuronal recording, which are not reliable in long-term monitoring applications because of the direct contact between the tissue and metal electrodes. In this paper, we propose a novel, wireless, and ultra-compact implantable device termed NanoNeuroRFID. At the core of this device, there is a magnetoelectric (ME) antenna array. ME antennas are smart and ultra-miniaturized (<200 μm diameter) and can perform multiple tasks. First, can harvest electromagnetic energy to power the NanoNeuroRFID system. Their limit of the detection for RF magnetic fields is 40 pT; second, they can sense quasi-static neuronal magnetic fields as small as 200 pT without direct contact to the tissue, allowing a long lifetime and reliable neural recording; and third, they can communicate with an external transceiver, and their operational frequency could be 10 to 100 s of MHz, where tissue loss is small.
TL;DR: X60 is introduced, the first SDR-based testbed for 60 GHz WLANs, featuring fully programmable MAC/PHY/Network layers, multi-Gbps rates, and a user-configurable 12-element phased antenna array, and it is found that a one-to-one MCS to SNR mapping is hard to obtain in typical indoor environments.
TL;DR: Simulations prove that the antenna array can cover the angle of over 180° with high gain over the frequency range from 26 to 40 GHz and has large coverage over the whole bandwidth and peak gain of 8 dBi at 28 and 38 GHz.
Abstract: The goal of this paper is to propose a new antenna array architecture that aims to solve the most known limitations of phased antenna arrays, resulting a good candidate for next 5G mobile handsets. The architecture consists of five quasi-Yagi antennas printed on the short edge of a Roger RO3003 substrate, pointing in different directions, and a switch to feed each antenna and steer the beam. Simulations prove that the antenna array can cover the angle of over 180° with high gain over the frequency range from 26 to 40 GHz. Alternative designs to make the structure more compact further demonstrate the validity of the concept. The optimized corner array of four elements is fabricated and passive and active measurements are performed with the Microwave Vision Group (MVG) Starlab 50 GHz. The results of the passive measurements are in accordance with the simulations and show that the proposed quasi-Yagi antenna array has large coverage over the whole bandwidth and peak gain of 8 dBi at 28 and 38 GHz. The active measurements of the array connected to the front end module (FEM) and integrated in the phone case further confirm the radiation properties of the switchable antenna array at 28 GHz in a quasi-real scenario.