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14 pages, 422 KiB

Open AccessArticle

3D Poisson-Based Neighborhood Capacity Analysis for Millimeter Wave Communications

by Massimiliano Comisso, Giulia Buttazzoni, Stefano Pastore, Francesca Vatta and Fulvio Babich

Sensors 2022, 22(6), 2098; https://doi.org/10.3390/s22062098 - 08 Mar 2022

Viewed by 1175

This paper proposes a theoretical model for evaluating the capacity of a millimeter wave (mmWave) source destination link when the nodes are distributed according to a three-dimensional (3D) homogeneous Poisson point process. In the presented analysis, different from the existing approaches, the destination [...] Read more.

This paper proposes a theoretical model for evaluating the capacity of a millimeter wave (mmWave) source destination link when the nodes are distributed according to a three-dimensional (3D) homogeneous Poisson point process. In the presented analysis, different from the existing approaches, the destination lies in an arbitrary location with respect to the source; thus, the link performance can be evaluated for a neighbor of any order. Moreover, the developed model relies on a realistic propagation environment, characterized by path loss attenuation and shadowing in line of sight (LoS), non-LoS, and outage link state conditions. The derived formulas, which are calculated in closed-form and validated by independent Monte Carlo simulations, are used to investigate the influence of the intensity parameter, of the antenna gain, and of the mmWave frequency band on the link capacity for any possible neighbor in a practical 3D scenario. Full article

(This article belongs to the Special Issue Millimeter-Wave Antenna Arrays: Design, Challenges, and Applications)

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13 pages, 3023 KiB

Open AccessArticle

Gaussian Approach for the Synthesis of Periodic and Aperiodic Antenna Arrays: Method Review and Design Guidelines

by Giulia Buttazzoni, Fulvio Babich, Stefano Pastore, Francesca Vatta and Massimiliano Comisso

Sensors 2021, 21(7), 2343; https://doi.org/10.3390/s21072343 - 27 Mar 2021

Cited by 2 | Viewed by 1951

Abstract

This paper presents a complete overview of the recently developed Gaussian approach for the synthesis of both periodic and aperiodic linear antenna arrays in conjunction with an exhaustive numerical investigation of the achievable performance. The position and excitation synthesis problems are jointly modeled [...] Read more.

This paper presents a complete overview of the recently developed Gaussian approach for the synthesis of both periodic and aperiodic linear antenna arrays in conjunction with an exhaustive numerical investigation of the achievable performance. The position and excitation synthesis problems are jointly modeled to enable a direct mutual comparison between the two strategies. To this aim, different parameter settings are selected to analyze the results in terms of achieved beamwidth and maximum sidelobe levels as a function of the array aperture and of the number of radiating elements. The insights inferred from this numerical investigation are exploited to derive a novel first-step procedure with the purpose of enabling an antenna engineer to quickly identify the most suitable design approach, thus reducing the time required for antenna system development. Full article

(This article belongs to the Special Issue Millimeter-Wave Antenna Arrays: Design, Challenges, and Applications)

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16 pages, 437 KiB

Open AccessArticle

Performance Analysis of Millimeter-Wave UAV Swarm Networks under Blockage Effects

by Haejoon Jung and In-Ho Lee

Sensors 2020, 20(16), 4593; https://doi.org/10.3390/s20164593 - 16 Aug 2020

Cited by 9 | Viewed by 2193

Abstract

Due to their high mobility, unmanned aerial vehicles (UAVs) can offer better connectivity by complement or replace with the existing terrestrial base stations (BSs) in the mobile cellular networks. In particular, introducing UAV and millimeter wave (mmWave) technologies can better support the future [...] Read more.

Due to their high mobility, unmanned aerial vehicles (UAVs) can offer better connectivity by complement or replace with the existing terrestrial base stations (BSs) in the mobile cellular networks. In particular, introducing UAV and millimeter wave (mmWave) technologies can better support the future wireless networks with requirements of high data rate, low latency, and seamless connectivity. However, it is widely known that mmWave signals are susceptible to blockages because of their poor diffraction. In this context, we consider macro-diversity achieved by the multiple UAV BSs, which are randomly distributed in a spherical swarm. Using the widely used channel model incorporated with the distance-based random blockage effects, which is proposed based on stochastic geometry and random shape theory, we investigate the outage performance of the mmWave UAV swarm network. Further, based on our analysis, we show how to minimize the outage rate by adjusting various system parameters such as the size of the UAV swarm relative to the distance to the receiver. Full article

(This article belongs to the Special Issue Millimeter-Wave Antenna Arrays: Design, Challenges, and Applications)

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20 pages, 7378 KiB

Open AccessArticle

Integrated LTE and Millimeter-Wave 5G MIMO Antenna System for 4G/5G Wireless Terminals

by Syeda Iffat Naqvi, Niamat Hussain, Amjad Iqbal, MuhibUr Rahman, Masoud Forsat, Seyed Sajad Mirjavadi and Yasar Amin

Sensors 2020, 20(14), 3926; https://doi.org/10.3390/s20143926 - 15 Jul 2020

Cited by 59 | Viewed by 6144

Abstract

This work demonstrates an integrated multiple-input multiple-output (MIMO) antenna solution for Long Term Evolution (LTE) and Millimeter-Wave (mm-wave) 5G wireless communication services. The proposed structure is comprised of a two-element LTE MIMO antenna, and a four-element 5G MIMO configuration with rectangular and circular [...] Read more.

This work demonstrates an integrated multiple-input multiple-output (MIMO) antenna solution for Long Term Evolution (LTE) and Millimeter-Wave (mm-wave) 5G wireless communication services. The proposed structure is comprised of a two-element LTE MIMO antenna, and a four-element 5G MIMO configuration with rectangular and circular defects in the ground plane. For experimental validation, the proposed structure is fabricated on a Rogers RO4350B substrate with 0.76 mm thickness. The overall substrate dimensions are 75 mm × 110 mm. The proposed structure is capable of operating at 5.29–6.12 GHz (LTE 46 and 47 bands) and 26–29.5 GHz (5G mm-wave) frequency bands. Additionally, the measured peak gain of 5.13 and 9.53 dB is attained respectively for the microwave and mm-wave antennas. Furthermore, the analysis of the MIMO performance metrics demonstrates good characteristics, and excellent field correlation performance across the operating bands. Furthermore, the analysis of the Specific Absorption Rate (SAR) and Power Density (PD) at the lower frequency band (5.9 GHz) and PD only at mm-Wave frequency band (28 GHz) verifies that the proposed antenna system satisfies the international human safety standards. Therefore, the proposed integrated MIMO antenna configuration ascertains to be a potential contender for the forthcoming communication applications. Full article

(This article belongs to the Special Issue Millimeter-Wave Antenna Arrays: Design, Challenges, and Applications)

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20 pages, 1112 KiB

Open AccessArticle

FDD Channel Estimation Via Covariance Estimation in Wideband Massive MIMO Systems

by José P. González-Coma, Pedro Suárez-Casal, Paula M. Castro and Luis Castedo

Sensors 2020, 20(3), 930; https://doi.org/10.3390/s20030930 - 10 Feb 2020

Cited by 5 | Viewed by 2825

Abstract

A method for channel estimation in wideband massive Multiple-Input Multiple-Output systems using hybrid digital analog architectures is developed. The proposed method is useful for Frequency-Division Duplex at either sub-6 GHz or millimeter wave frequency bands and takes into account the beam squint effect [...] Read more.

A method for channel estimation in wideband massive Multiple-Input Multiple-Output systems using hybrid digital analog architectures is developed. The proposed method is useful for Frequency-Division Duplex at either sub-6 GHz or millimeter wave frequency bands and takes into account the beam squint effect caused by the large bandwidth of the signals. To circumvent the estimation of large channel vectors, the posed algorithm relies on the slow time variation of the channel spatial covariance matrix, thus allowing for the utilization of very short training sequences. This is possibledue to the exploitation of the channel structure. After identifying the channel covariance matrix, the channel is estimated on the basis of the recovered information. To that end, we propose a novel method that relies on estimating the tap delays and the gains as sociated with each path. As a consequence, the proposed channel estimator achieves low computational complexity and significantly reduces the training overhead. Moreover, our numerical simulations show better performance results compared to the minimum mean-squared error solution. Full article

(This article belongs to the Special Issue Millimeter-Wave Antenna Arrays: Design, Challenges, and Applications)

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20 pages, 3137 KiB

Open AccessArticle

Iterative Analog–Digital Multi-User Equalizer for Wideband Millimeter Wave Massive MIMO Systems

by Roberto Magueta, Daniel Castanheira, Pedro Pedrosa, Adão Silva, Rui Dinis and Atílio Gameiro

Sensors 2020, 20(2), 575; https://doi.org/10.3390/s20020575 - 20 Jan 2020

Cited by 12 | Viewed by 3189

Abstract

Most of the previous work on hybrid transmit and receive beamforming focused on narrowband channels. Because the millimeter wave channels are expected to be wideband, it is crucial to propose efficient solutions for frequency-selective channels. In this regard, this paper proposes an iterative [...] Read more.

Most of the previous work on hybrid transmit and receive beamforming focused on narrowband channels. Because the millimeter wave channels are expected to be wideband, it is crucial to propose efficient solutions for frequency-selective channels. In this regard, this paper proposes an iterative analog–digital multi-user equalizer scheme for the uplink of wideband millimeter-wave massive multiple-input-multiple-output (MIMO) systems. By iterative equalizer we mean that both analog and digital parts are updated using as input the estimates obtained at the previous iteration. The proposed iterative analog–digital multi-user equalizer is designed by minimizing the sum of the mean square error of the data estimates over the subcarriers. We assume that the analog part is fixed for all subcarriers while the digital part is computed on a per subcarrier basis. Due to the complexity of the resulting optimization problem, a sequential approach is proposed to compute the analog phase shifters values for each radio frequency (RF) chain. We also derive an accurate, semi-analytical approach for obtaining the bit error rate (BER) of the proposed hybrid system. The proposed solution is compared with other hybrid equalizer schemes, recently designed for wideband millimeter-wave (mmWave) massive MIMO systems. The simulation results show that the performance of the developed analog–digital multi-user equalizer is close to full-digital counterpart and outperforms the previous hybrid approach. Full article

(This article belongs to the Special Issue Millimeter-Wave Antenna Arrays: Design, Challenges, and Applications)

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16 pages, 808 KiB

Open AccessArticle

Geometrical Synthesis of Sparse Antenna Arrays Using Compressive Sensing for 5G IoT Applications

by Giulia Buttazzoni, Fulvio Babich, Francesca Vatta and Massimiliano Comisso

Sensors 2020, 20(2), 350; https://doi.org/10.3390/s20020350 - 08 Jan 2020

Cited by 24 | Viewed by 3694

Abstract

One of the main targets of the forthcoming fifth-generation (5G) cellular network will be the support of the communications for billions of sensors and actuators, so as to finally realize the Internet of things (IoT) paradigm. This pervasive scenario unavoidably requires the design [...] Read more.

One of the main targets of the forthcoming fifth-generation (5G) cellular network will be the support of the communications for billions of sensors and actuators, so as to finally realize the Internet of things (IoT) paradigm. This pervasive scenario unavoidably requires the design of cheap antenna systems with beamforming capabilities for compensating the strong attenuations that characterize the millimeter-wave (mmWave) channel. To address this issue, this paper proposes an iterative algorithm for sparse antenna arrays that enables to derive the number of elements, their amplitudes, phases, and positions in the presence of constraints on the far-field pattern. The algorithm, which relies on the compressive sensing approach, is formulated by transforming the original nonconvex optimization problem into a convex one. To prove the suitability of the conceived solution for 5G IoT mmWave applications, numerical examples and comparisons with other existing methods are provided, considering synthesis problems with different pattern and aperture specifications. Full article

(This article belongs to the Special Issue Millimeter-Wave Antenna Arrays: Design, Challenges, and Applications)

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Other

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11 pages, 5369 KiB

Open AccessLetter

mmWave High Gain Planar H-Shaped Shorted Ring Antenna Array

by Young-Jun Kim, Ye-Bon Kim and Han Lim Lee

Sensors 2020, 20(18), 5168; https://doi.org/10.3390/s20185168 - 10 Sep 2020

Cited by 8 | Viewed by 2829

Abstract

A new design approach for a mmWave high gain planar antenna is presented. The proposed method can increase antenna directivity with a minimally enlarged radiation patch while the operation frequency is still matched at a higher target frequency. The fundamental structure of the [...] Read more.

A new design approach for a mmWave high gain planar antenna is presented. The proposed method can increase antenna directivity with a minimally enlarged radiation patch while the operation frequency is still matched at a higher target frequency. The fundamental structure of the proposed antenna is configured by a H-shaped and slot-loaded patch with a shorting pin symmetrically located across a signal excitation port. Further, to match the operation frequency with the frequency for the highest achievable gain, a vertically stacked matching conductor was inserted along the signal feed path between the radiation patch and the ground layer. The proposed single antenna showed the simulated directivity of 9.46 dBi while the conventional patch with a same dielectric had 8.07 dBi. To verify practical performance, a 2 × 2 array antenna was fabricated at 28 GHz and showed the measured gain of 12.5 dBi including the array feed loss. Full article

(This article belongs to the Special Issue Millimeter-Wave Antenna Arrays: Design, Challenges, and Applications)

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10 pages, 3292 KiB

Open AccessLetter

Design and Optimization for 77 GHz Series-Fed Patch Array Antenna Based on Genetic Algorithm

by Shuo Yang, Lijun Zhang, Jun Fu, Zhanqi Zheng, Xiaobin Zhang and Anmou Liao

Sensors 2020, 20(11), 3066; https://doi.org/10.3390/s20113066 - 28 May 2020

Cited by 4 | Viewed by 5282

Abstract

This paper proposes a method for designing a 77 GHz series-fed patch array antenna. Based on the traditional genetic algorithm, the study explores different array topologies consisting of the same microstrip patches to optimize the design. The main optimization goal is to reduce [...] Read more.

This paper proposes a method for designing a 77 GHz series-fed patch array antenna. Based on the traditional genetic algorithm, the study explores different array topologies consisting of the same microstrip patches to optimize the design. The main optimization goal is to reduce the maximum sidelobe level (SLL). A 77 GHz series-fed patch array antenna for automotive radar was simulated, fabricated, and measured by employing this method. The antenna length was limited to no longer than 3 cm, and the array only had a single compact series with the radiation patch about 1.54 mm wide. In the genetic algorithm used for optimization, the maximum sidelobe level was set equal to or less than −14 dB. The measurement results show that the gain of the proposed antenna was about 15.6 dBi, E-plane half-power beamwidth was about ±3.8°, maximum sidelobe level was about −14.8 dB, and H-plane half-power beamwidth was about ±30° at 77 GHz. The electromagnetic simulation and the measurement results show that the 77 GHz antenna designed with the proposed method has a better sidelobe suppression by over 4 dB than the traditional one of the same length in this paper. Full article

(This article belongs to the Special Issue Millimeter-Wave Antenna Arrays: Design, Challenges, and Applications)

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