Mm-wave Antenna Array Research Articles

Dual-Band Coradiator Antenna Employing Cascaded Triangular Cavities With a Steerable Beam in the Millimeter-Wave Band

A dual-band coradiator antenna with a beam-scanning capability for the sub-6 GHz andmm-wave bands is proposed in this paper. First, four subarrays based on cascaded triangular cavities are arranged using a mirror operation to form the mm-wave antenna array. Then, four mm-wave subarrays are connected at the position where the electric field is at a minimum on their edges. Lastly, the entire mm-wave array structure resonates in the microwave band, which can be equivalent to a shorted quarter-wavelength patch antenna in the sub-6 GHz band. Hence, the same radiator can work as both a sub-6 GHz antenna and a mm-wave antenna array with broadside patterns in both cases. Attributed to the novel co-radiator structure, the proposed design is simple and compact. An interdigital coupled line with a high-pass filtering characteristic is inserted into each mm-wave feeding line to enhance the isolation. Besides, two parasitic patches are loaded to increase the microwave bandwidth. The experimental results show that the peak gain at 2.56 GHz is 3.2 dBi and at 28 GHz is 14.3 dBi for the sub-6 GHz and mm-wave bands, respectively. The isolation among different feeding ports is greater than 15 dB and the mm-wave array also provides ±38° beam scanning performance.

Design and Optimization of Wideband Rectangular‐Framed Pi‐Shaped mmWave Antenna Array for 5G Applications

Design and Optimization of Wideband Rectangular‐Framed Pi‐Shaped mmWave Antenna Array for 5G Applications

Varactor-Based Frequency-Reconfigurable Dual-Polarized mm-Wave Antenna Array for Mobile Devices

Varactor-Based Frequency-Reconfigurable Dual-Polarized mm-Wave Antenna Array for Mobile Devices

Broadband Dual-Polarized mm-Wave Antenna Array With Grating Structure for Mobile Devices

In this letter, a broadband dual-polarized millimeter-wave (mm-wave) antenna array for smartphone application is proposed. Different from previous designations, this array utilizes circular-shaped slot to realize a wideband dual-polarized radiation. In addition, a novel grating structure is adopted for circular slot. With the proposed structure, a better radiation performance is realized. Operating frequency of this antenna array is measured from 26 to 38 GHz, which is calculated for more than 30% of bandwidth. In its operating band, return loss of each antenna units exceeds 10 dB and isolation between V-pol and H-pol reaches more than 15 dB. In addition, total efficiency of whole antenna array exceeds −2 dB. Peak realized gain of this antenna array reaches 12.6 and 12.5 dBi for V-pol and H-pol, respectively. Hence, the proposed antenna structure can be a promising candidate for mm-wave application in smartphone.

A novel beamforming technique using mmWave antenna arrays for 5G wireless communication networks

Millimeter wave (mmWave) multiple-input multiple-output (MIMO) and beamforming technologies are most likely the integral parts and the key enablers of 5G-and-Beyond (5G-B) wireless communication systems. From that perspective, this manuscript proposes an efficient digital beamforming technique for 5G applications. The suggested approach is formulated based on a reliable sampling technique that effectively samples the interference-plus-noise covariance matrix (IPNCM) to construct an efficient projection matrix (PM). The proposed technique is therefore named interference-plus-noise PM (IPNPM) beamformer. Next, a compact-size rectangular microstrip antenna operating at 49.3 GHz having 1.7 GHz potential bandwidth is designed using CST microwave studio. The designed antenna is subsequently used to model a 32-element uniform linear array (ULA) representing a typical 5G base station. The elements of the modeled ULA are then manually fed with the complex-weights generated from the proposed beamformer to produce high-power beams and deep nulls toward the desired and undesired locations, respectively. To further improve the beamformer performance in terms of minimizing radiating power within undesired regions, an iterative sidelobe level (SLL) suppression technique is developed and integrated with the proposed beamformer. The conducted theoretical analysis justifies that the IPNPM beamformer requires less arithmetic operations than the well-known beamforming approaches. To reveal the benefits of the proposed technique, the array radiation pattern based on the proposed beamformer is plotted and compared with those for the three widely used approaches. An intensive Monte Carlo simulation is also carried out in which the IPNPM beamformer performance is systemically compared with the popular approaches based on the output signal to interference-plus-noise ratio (SINR) criterion. The achieved results demonstrate that the proposed approach is superior and surpasses the rival algorithms in terms of generating deeper nulls, enhanced output SINR, and lower execution time. It is also demonstrated that, unlike the existing SLL reduction techniques, the newly developed SLL suppressor reduces the SLLs of the proposed beamformer to a predefined threshold value (i.e., −24 dB) after few iterations.

A New mm-Wave Antenna Array with Wideband Characteristics for Next Generation Communication Systems

This paper presents a planar multi-circular loop antenna with a wide impedance bandwidth for next generation mm-wave systems. The proposed antenna comprises three circular rings with a partial ground plane with a square slot. The resonating structure is designed on a 0.254 mm thin RO5880 substrate with a relative permittivity of 2.3. The single element of the proposed design showed a resonance response from 26.5 to 41 GHz, with a peak gain of 4 dBi and radiation efficiency of 96%. The proposed multicircular ring antenna element is transformed into a four-element array system. The array size is kept at 18.25 × 12.5 × 0.254 mm3 with a peak gain of 11 dBi. The antenna array is fabricated and measured using the in-house facility. The simulated and measured results are well agreed upon and are found to be suitable for mm-wave communication systems.

Corrigendum to “Square-Framed T Shape mmwave Antenna Array at 28 GHz for Future 5G Devices”

Corrigendum to “Square-Framed <i>T</i> Shape mmwave Antenna Array at 28 GHz for Future 5G Devices”

Development Of A Millimeter Wave Eight-Element Phased Array Antenna for 5G Mobile Communications

The fifth generation (5G) mobile communications systems demand millimeter wave (mmWave) bands of the electromagnetic spectrum beside the current sub-6 GHz frequencies. Allocation of mmWave frequencies for the cellular systems will ensure more capacity and higher speed links. For the last few years wireless communications societies in industry and academia have put significant research effort to develop novel and efficient antenna architectures. We need brand-new antenna structures that can overcome the challenges of 5G communications environment such as high propagation loss of mmWaves and the large bandwidth demand of the planned networks. In this paper, a microstrip mmWave antenna array for 5G mobile phone terminals is introduced. First, the single antenna element with the rectangular patch radiator is investigated. The numerical investigation is carried out with a full-wave electromagnetic solver. The single antenna design operates between 27.1 GHz – 28.95 GHz frequencies. The proposed antenna based on microstrip approach shows low profile characteristics without compromising performance. A maximum gain of ~7.7 dBi is achieved within the operation band. Then eight-element phased array implementation of the proposed antenna is analyzed. Uniformly spaced linear array method is used with ~λ/2 spacing in the configuration. The eight-element array boosts the maximum total gain value up to ~ 15 dBi, and yields beam steering at broadside up to ∓50° with low side lob levels (SLL). Furthermore, the proposed phased array design is compact with the dimensions of 10 mm×48.6 mm×0.51 mm, and therefore it is compatible with the mmWave band radio frequency integrated circuit (RFIC) transceivers.

Square-Framed T Shape mmwave Antenna Array at 28 GHz for Future 5G Devices

In this research, a novel T shape antenna is proposed for millimetre-wave (mmwave) 5G systems. Designed on 0.254 mm thin Roggers 5880 substrate with a dielectric constant of 2.3 and the loss tangent of 0.0009, the proposed antenna offers a wideband characteristics of nearly 8 GHz with gain of 4.25 dBi for single element. Based on these characteristics, the single element is further constructed into a four-element linear array with a compact size of 18.5 × 24 mm2 The proposed antenna array exhibited dual beam radiation patterns with a high realized gain of 11.5 dBi and 94% efficiency. The measured results from the fabricated prototype well agree with the simulated results and thus, therefore, make the proposed antenna system a well-suited candidate for future mmwave devices.

A Review of Antenna Array Technologies for Point-to-Point and Point-to-Multipoint Wireless Communications at Millimeter-Wave Frequencies

With the introduction of 5G communication systems operating in the mm-wave frequency range, new opportunities in terms of multimedia services and applications will become available. For this to happen, several technical challenges from an antenna standpoint need to be addressed. The achievements of high-gain characteristics and agile beamforming with wide-scan capabilities are the main targets of the ongoing research on mm-wave antenna arrays. In this paper, an up-to-date overview of antenna array technology for wireless communications at mm-wave frequencies is given. Particular focus is put on the review of the state-of-the art and most advanced antenna array concepts for point-to-point and point-to-multipoint radio links at said frequencies. Various figures of merit are assessed for a comprehensive analysis and bench marking of the technical solutions investigated in the presented survey.

Achieving 5G NR mmWave Indoor Coverage Under Integrated Access Backhaul

In this article, we introduce a novel millimeter wave (mmWave) access architecture, called mmWave over cable (mmWoC), for achieving effective indoor coverage under integrated access backhaul. The proposed mmWave access architecture is characterized by using an analog link over local area network cables to relay the frequency-converted signals between the mmWave small cell station at the outdoor and the mmWave antenna array in the indoor, so as to ensure line-of-sight transmissions for the indoor user equipment. We first develop a precoding process for the proposed mmWoC architecture where a cascaded radio–radio (R–R) mmWave channel (R–R channel) is seen at the mmWave base station. Then, rate analysis is provided for both the cascaded R–R channel and the cascaded radio–cable–radio channel (R–C–R channel). Furthermore, we investigate an efficient yet simple resource mapping scheme between the antenna signals and the cable subcarriers, namely nonconfigurable air-to-cable (NC-A2C), which ensures each cable subcarrier with sufficient capacity to meet the fifth-generation new radio (5G NR) requirement by manipulating the cable input powers. Simulation results indicate that the proposed NC-A2C scheduler can efficiently trade the capacity off for better control simplicity and cost effectiveness; and the proposed precoder can work well on the R–C–R indoor environment under the mmWoC architecture.

Test Reduction for Power Density Emitted by Handset mmWave Antenna Arrays

The exposure to electromagnetic field (EMF) from phased antenna arrays integrated into wireless devices operating at the millimeter-wave (mmWave) part of the spectrum should be evaluated in terms of power density (PD). Two aspects related to test reduction when evaluating the radiation from handset antenna arrays are considered. First, the peak PD decay with the distance from 4-elements antenna arrays is analyzed. The focus is on finding the size of the volume around the handset beyond which the PD is so low that its measurement can be omitted. By limiting the measurements to the inside of the exposed volume, the total test time is reduced. Antenna configurations that are representative for current trends in handset technology are chosen: arrays of half-wavelength dipoles and patches operating at 26 GHz, 28 GHz, and 39 GHz, and having inter-element spacing either $0.5\lambda $ or $0.9\lambda $ . The second investigation aims to determine the critical distance between two 4-elements phased arrays for which the peak PD when the two arrays operate simultaneously is similar to the peak PD when only one array operates at the time. The study shows the configurations for which the number of tests can be reduced while having sufficiently accurate results.

Millimeter Wave MIMO-Based Depth Maps for Wireless Virtual and Augmented Reality

Augmented and virtual reality systems (AR/VR) are rapidly becoming key components of the wireless landscape. For immersive AR/VR experience, these devices should be able to construct accurate depth perception of the surrounding environment. Current AR/VR devices rely heavily on using RGB-D depth cameras to achieve this goal. The performance of these depth cameras, however, has clear limitations in several scenarios, such as the cases with shiny objects, dark surfaces, and abrupt color transition among other limitations. In this paper, we propose a novel solution for AR/VR depth map construction using mmWave MIMO communication transceivers. This is motivated by the deployment of advanced mmWave communication systems in future AR/VR devices for meeting the high data rate demands and by the interesting propagation characteristics of mmWave signals. Accounting for the constraints on these systems, we develop a comprehensive framework for constructing accurate and high-resolution depth maps using mmWave systems. In this framework, we developed new sensing beamforming codebook approaches that are specific for the depth map construction objective. Using these codebooks, and leveraging tools from successive interference cancellation, we develop a joint beam processing approach that can construct high-resolution depth maps using practical mmWave antenna arrays. Extensive simulation results highlight the potential of the proposed solution in building accurate depth maps. Further, these simulations show the promising gains of mmWave based depth perception compared to RGB-based approaches in several important use cases.

Dynamic Resource Allocation in UAV-Enabled mmWave Communication Networks

Unmanned aerial vehicle (UAV)-enabled cellular architecture over the millimeter-wave (mmWave) frequency band is likely to be the best solution for on-demand high data rate service provisioning in the next generation communication networks. The beam formed by the mmWave antenna array is highly directional and requires multiple-beam scans to cover the entire area. This work presents a novel sectoring approach to ensure coverage of the whole area. The side lobe gain of the antenna array is taken into consideration, which generates substantial interference in other sectors. The expression for the probability distribution of the signal-to-interference-plus-noise ratio due to simultaneous transmissions in different sectors is derived in the downlink communication scenario. To limit interference in the concurrent transmission strategy, a threshold on power spillage from adjacent sectors is placed. For this topology, a resource allocation problem is formulated aiming to maximize the sum rate while ensuring a minimum rate guarantee to each user. It is observed that sum-rate variation with height is unimodal. The sum power and backhaul capacity constraints are accounted. This optimization problem is mixed-integer nonconvex programming. Hence, it is solved using the Lagrangian dual decomposition method, which provides an asymptotic global optimal solution. Since this method is computationally intensive, a suboptimal solution is proposed. Simulation results demonstrate convergence to an optimal solution, and it is observed that backhaul link capacity restricts the sum rate. Numerical results are presented for multiple representative field environments consisting of different types of built-up areas. It is observed that the transmitter antenna array sidelobe has a strong impact on the performance as compared to the ideal scenario without sidelobe, which overestimates the total sum rate by a factor of 3.

Low-Complexity Failed Element Diagnosis for Radar-Communication mmWave Antenna Array with Low SNR

The millimeter-wave (mmWave) antenna array plays an important role in the excellent performance of wireless sensors networks (WSN) or unmanned aerial vehicle (UAV) clusters. However, the array elements are easily damaged in its harsh working environment but hard to be repaired or exchanged timely, resulting in a serious decline in the beamforming performance. Thus, accurate self-diagnosis of the failed elements is of great importance. In previous studies, there are still significant difficulties for large-scale arrays under extremely low SNR. In this paper, a diagnosis algorithm with low complexity and high reliability for the failed elements is proposed, which is based on a joint decision of communication signal and sensing echoes. Compared with the previous studies, the complexity of the algorithm is reduced by the construction of low-dimensional feature vectors for classification, the decoupling of the degree of arrival (DOA) estimation and the failed pattern diagnosis, with the help of the sub-array division. Simulation results show that, under an ultra-low SNR of −12.5 dB for communication signals and −16 dB for sensing echoes, an accurate self-diagnosis with a block error rate lower than 8% can be realized. The study in this paper will effectively promote the long-term and reliable operation of the mmWave antenna array in WSN, UAV clusters and other similar fields.

Efficient design of compact millimeter wave microstrip linear array with bandwidth enhancement and sidelobe reduction

In this article, a novel linear mmWave antenna array with series-feed network is proposed to enhance the bandwidth and reduce sidelobe level without increasing the patch size. The proposed linear array is consisted of four identical wideband array elements, which are all under operation TM10 and TM02 modes by loading shorting pin and rectangular slots. Additionally, through loading symmetry circle-shaped slots for the four elements, impedance matching of linear array is achieved. Furthermore, multi-parameters unified-optimization (MPUO) based on imperial competition algorithm (ICA) is proposed to uniformly optimize all linear array parameters. To verify this design, the proposed linear array is fabricated with a small patch area of 7.5 × 3.914 × 0.254 mm3. The measured results show that the bandwidth is enhanced to 2.05GHz, which is 0.57GHz wider than that of simulation. The simulated peak gain reaches 13dBi while the sidelobe level is reduced to about −19 dB at 28.6GHz. Moreover, the computation cost using MPUO is reduced by 98.12% compared with that of independent parameters optimization.

Millimeter Wave Communication With Active Ambient Perception

In existing communication systems, the channel state information of each user equipment (UE) should be repeatedly estimated when it moves to a new position or when another UE takes its place. The underlying ambient information, including the specific layout of potential reflectors, which provides more detailed information about all UEs’ channel structures, has not been fully explored and exploited. In this paper, we rethink the mm-wave channel estimation problem in a new and indirect way, i.e., instead of estimating the resultant composite channel response at each time, and for any specific location, we first conduct the ambient perception exploiting the fascinating radar capability of a mm-wave antenna array and then accomplish the location-based sparse channel reconstruction. In this way, the sparse channel for a quasi-static UE arriving at a specific location can be rapidly synthesized based on the perceived ambient information, thus greatly reducing the signaling overhead and online computational complexity. Based on the reconstructed mm-wave channel, single-beam mm-wave communication is designed and evaluated which shows an excellent performance. Such an approach, in fact, integrates the radar with communication, which may possibly open a new paradigm for future communication system design.

Realization of a Tapered Slot Array as Both Decoupling and Radiating Structure for 4G/5G Wireless Devices

As a combination of microwave Multiple-Input Multiple-Output (MIMO) antenna system and mm-wave antenna array, an integrated design is proposed to provide multi-band, high port isolation, and high gain antenna solution for 4G/5G wireless devices. In this work, an array of tapered slots is used as a decoupling structure at microwave frequency and as an antenna array at mm-wave frequency. The proposed geometry consists of a dual-band monopole MIMO antenna system operating at 4G (2.6 GHz) and 5G (3.5 GHz) sub-6 GHz bands. The wideband port isolation of more than 25 dB is achieved by introducing a tapered slot array structure. One of the key design features is the utilization of these slots as an antenna array with a peak realized gain of 15 dBi at 28 GHz, making this array dual-functional, thus more feasible for compact 4G/5G handheld devices. The proposed design is printed on an RO-5880 substrate with an overall size of 70 mm × 50 mm × 0.51 mm. The measured -10-dB impedance matching bandwidth covers two sub-6 GHz bands (from 2.45 GHz to 2.85 GHz and from 3.18 GHz to 3.68 GHz), and the wide mm-wave band from 25 GHz to 30 GHz.

An Inclusive Survey on Array Antenna Design for Millimeter-Wave Communications

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.

Unveiling Capacity Gains in Ultradense Networks: Using mm-Wave NOMA

Millimeter-wave (mm-wave) communications and nonorthogonal multiple access (NOMA) are two important techniques to achieve high data rates in fifth-generation (5G) ultradense networks (UDNs). Due to interference that is intentionally added during the superpositioned transmissions with NOMA, an additional power budget is required to maintain the target block error rate (BLER). This necessitates the consideration of new approaches to ensure the power efficiency of NOMA systems. In this article, we show that this additional required power can be implemented using the directional transmission capabilities offered by mm-wave antenna arrays. Through the use of our small cells cluster simulations, we investigate the performance of NOMA in mm-wave frequency bands with consideration to the total system capacity, hybrid resource allocation, pairing probability, and power requirements. We demonstrate that a 30d beamwdith, as opposed to a typical 120? beamwidth, can result in a 20% system-capacity gain without requiring any extra transmission power. Our results indicate novel tradeoffs between system capacity, pairing probability, and transmission power in mm-wave NOMA networks owing to the effect of beamwidth variations. We conclude by summarizing the future challenges of NOMA in mm-wave bands.