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In this article, the design of a radiation beam-reconfigurable antenna using the reflector pins is presented. The reflector pins make a short or open connection with the ground, via switches and Plated Through Hole (PTH), which helps in controlling radiation characteristics of the proposed antenna. This design contains a simple 3D printed Cylindrical Dielectric Resonator Antenna that is located at the center of the substrate. The beam-sweeping of the antenna is attained by operating switches in different combinations of ON and OFF states. The reconfigurable CDRA operates at 4.5 GHz and covers all azimuth angles in four steps with a maximum measured gain of 6.6 dBi. This beam-switching antenna is very advantageous because of its trait of eliminating fade zones and beamforming.

International audience; We present a photonically-excited antenna array at E-band for scanning by beam switching in wireless links. First, we discuss the proposed technique applied to photonic-enabled (sub)millimeter-wave transmitters. Next, we present the proposed solution; it consists of two sub-arrays of stacked patches as primary feeds of a Polytetrafluoroethylene (PTFE) lens, with one photodiode feeding each sub-array. To validate the assembly, the return loss and radiation patterns have been measured for one of the sub-arrays excited with a coplanar probe. In turn, the lens illuminated by one of the sub-arrays yields a directivity of 27 dBi. The radiation patterns measured for the transmitter module (including the lens) are in very good agreement with full-wave simulations, and they show that excitation of one of either sub-arrays allows beam switching between 2.7 with a beam crossover at 3 dB. Finally, we have tested the transmitter in a 0.6 m wireless link. Depending on the position of the detector and on which subarray is excited, we have accomplished 5 Gbps transmission for on-off-keying modulation and direct detection (BER = 1E11). The system constitutes an initial proof of photonic-assisted beam switching for mm-wave transmitters enabling broadband operation with a directive and switchable beam. IEEE

A novel fixed-frequency beam switchable dual-beam antenna array is presented, which consists five dual-beam leaky-wave antenna (LWA) elements designed on substrate integrated waveguide (SIW) and integrated together on a common substrate. The LWAs work on fundamental wave and -1th spatial harmonic wave simultaneously and excite two symmetrical radiation beams in forward and backward direction respectively. In order to realize beam switching, three voltage-driven radio frequency chip switches (CSW-RFs) are used and integrated behind the antenna aperture. Since the periodic slot in LWA causes open stopband at the operating frequency, so the staggered radius amplification of local vias in the via walls of SIW is performed to suppress the open stopband. In addition, electromagnetic band-gap (EBG) structures, capable of reducing coupling between neighboring antenna elements, are embedded in between LWAs. The proposed dual-beam antenna array with beam switching capability between ±35, ±45, ±55, ±65 and ±75 degrees at 28 GHz are simulated, fabricated and measured. Both analysis and measurement results show that the proposed antenna array exhibits an excellent performance, which can be used in fixed-frequency beam-switching millimeter wave communication.

This paper presents designs and prototypes of low cost multiple input multiple output (MIMO) antennas for 5G and millimetre-wave (mm-wave) applications. The proposed MIMOs are fabricated using 3D printing and are able deliver beams in multiple directions that provide continuous and real time coverage in the elevation of up to F300 without using phase shifters. This equips the proposed MIMO with a superior advantage of being an attractive low cost technology for 5G and mm-wave applications. The proposed MIMO antennas operate at the 28 GHz 5G band, with wide bandwidth performance exceeds 4 GHz and with beam switching ability of up to F300 in the elevation plane. The direction of the main beam of the single element antenna in the MIMO is steered over the entire bandwidth through introducing 3D printed walls with different heights on the side of the 3D printed radiating antenna. Unlike all other available beam steering techniques; the proposed wall is not only able to change the direction of the beam of the antenna, but also it is able to increase the overall directivity and gain of the proposed antenna and MIMO at the same time over the entire bandwidth.

Due to the increase in the number of users, beam switching is used for suppressing interference, which leads to higher computational complexity in multi-cell millimeter wave communications. In order to resolve this problem, a beam interference model is introduced, and a lower complexity beam interference suppression algorithm based on user grouping is proposed. The proposed algorithm operates beam switching and multi-cell cooperative transmission for a part of the users when there exists beam interference due to high user density. In particular, considering the distinct interference suffered by each user, the proposed dual-threshold user grouping method can effectively solve the frequent switching problem at the base station caused by multi-cell cooperative transmission in multi-cell environments. Simulation results show that the proposed algorithm can reduce the computational complexity of beam switching and approach ideal system capacity, compared with conventional interference suppression algorithms that do not involve grouping of users. Keywords: Millimeter wave, Beam interference, Beam switching, User grouping, Multi-cell cooperative transmission

Conférence virtuelle; International audience; We present a photonic transmitter at E-band for beam switching in mm-wave wireless links. First, we discuss the trade-offs between beam switching and beam steering with arrays of photonic transmitters. Then, the designed transmitter is presented; it includes two 2×2 sub-arrays of stacked patches fed independently by two photodiodes. The transmitter is placed at the focal plane of a PTFE lens to increase the overall gain. Excitation of either sub-array allows 1D beam witching between ±2.7º for accurate beam alignment or reconfigurable links.

International audience; This abstract describes the first design and assembly of a photonically-excited antenna at E-band for beam switching in millimeter-wave wireless links. The designed antenna consists of two arrays of stacked patches, with one photodiode feeding each array. The stacked patch provides an impedance bandwidth larger than 23 % and a stable radiation pattern over the E-band. The array is combined with a lens to increase the overall gain. Excitation of either patch array allows beam steering between ±2.7° for accurate beam alignment. © 2020 IEEE.

This paper presents a MIMO antenna for 5G mm-wave applications. The proposed MIMO is capable of providing continues beam cover in the elevation for up to ± 30° without using phase shifters. The proposed MIMO is fabricated using 3D printing and it has good measured performance over wide band. The proposed MIMO operates at 28 GHz 5G band with a measured bandwidth of more than 4 GHz and a measured peak gain of higher than 10 dBi.

In this paper, we propose a reconfigurable metasurface antenna for beam switching applications. The reconfigurable metasurface is formed by uniformly distributed double-split square rings loaded with positive-intrinsic-negative (PIN) diodes for dual operations of a wave reflector and a wave director. Specifically, when the PIN diodes are forward biased, an epsilon-negative (ENG) metasurface is realized which reflects all incident waves with appropriate polarization; when the diodes are reverse biased, at the same operating frequency, a mu-near-zero (MNZ) metasurface is acquired which directs wave propagation. For excitation, a dipole radiator loaded with the same type of PIN diode is designed. Simulation and measurement results show good agreement and verify the beam switching functionality of the proposed metasurface antenna.

This study proposes a cylindrical conformal array antenna (CCAA) for fifth-generation (5G) micro base station applications. The CCAA is composed of five Chebyshev flexible linear array antennas (LAAs) with a circumferentially uniform arrangement on the cylindrical surface. The LAA with a logarithmic periodic arrangement is constructed by synthesizing the current amplitude distribution coefficients in elements with the Chebyshev method. The LAA with a half-power bandwidth (HPBW) wider than 76° (-8.41° to 38.58°) and a peak gain greater than 10 dBi is fabricated via the micro-electromechanical system process. Cost-performance analysis shows that five is the best number of linear arrays. To achieve omnidirectional switching scanning of the circumferential section, five LAAs wrapped on the cylindrical surface are individually excited by connecting a radio frequency semiconductor switch to the exciting ports of an eight-way power divider. Moreover, beam-switch scanning of the CCAA is measured with the aid of a standard anechoic chamber. The irradiated performance with low mutual coupling and high realized gain is verified to be irrelevant to the structural variation of various flexible experiments of LAAs wrapped around a cylindrical surface. The CCAA with beam-switch scanning operates at 26 GHz and belongs to the 5G millimeter-wave band. Results show the proposed antenna achieves omnidirectional scanning property in the H plane and has a HPBW of only 9.08° in the E plane. The performances of the CCAA present potential advantage in flexible terminal equipment wireless communication.

Power dividers are critical components for mm-wave applications. They are used in antenna feeding structures to provide the suitable excitation in the antenna array systems and deployed in microwave smart beam switching subsystems. In this article a dual gap wideband in-phase power divider is presented. The bandwidth starts at 19 and ends at 40 GHz. We are targeting with this design both the k and ka bands. The proposed design achieved a very deep matching level below −18 dB.

We report results based on millimeter wave vehicle-to-infrastructure (V2I) channel measurements carried out in an urban street environment, down-town Vienna, Austria. Signal to noise ratios (SNRs) have been acquired at 60 GHz with 100 MHz bandwidth. Two horn antennas were used on a moving transmitter vehicle: one horn emitted a beam towards the horizon and the second horn emitted an elevated beam at 15-degrees up-tilt. This configuration was chosen to assess the impact of beam elevation on V2I communication channel variability. The variability of the V2I channel is shown by density estimates of the channel transfer function magnitudes. The channel changes severely along the vehicle trajectory in an urban street scenario. Density estimates in the region with clear wide-angle view are bimodal and motivate a two-wave with diffuse power (TWDP) fading model for V2I communication with horizontal and elevated antenna beams. We compare three different strategies for beam switching: fixed, geometry-based, and SNR-based.

The vehicle-to-infrastructure (V2I) communication can capture infrastructure data and provide travelers with real-time traffic information, which can significantly improve road safety. Millimeter-wave (mmWave) with large bandwidth has been introduced as a key technology to achieve ultra-reliable, low latency, and high-data-rate V2I communication. In this paper, the V2I communication in mmWave band (22.1GHz-23.lGHz) is characterized for typical urban and highway scenarios. By considering the different deployments involving overtaking and traffic flow, the simulations are conducted by employing the self-developed ray-tracing. The key channel parameters, including received power, Rician K-factor, root-mean-square delay spread and angular spreads, are analyzed and compared between different deployments. Moreover, the impacts of the multiple antennas and beam switching technologies at the vehicle are evaluated as well. This work aims to help the researchers understand the channel characteristics of the V2I communication in mmWave band and support communication system design for vehicular communications.

A switchable multibeam antenna array with a compact planar feeding network is presented. Operating within 1 GHz bandwidth at 28 GHz, this 4 × 4 antenna can generate onebeam, two-beam and four-beam patterns based on two phase states, which are controlled by the reconfigurable feeding network. The whole structure is validated by simulating in CST Studio. The antenna is a promising candidate in millimeterwave Massive MIMO for applications where multiple beams are required simultaneously.

A design for beam-switching antennas is proposed in this study. A cylindrical cavity with a reconfigurable conformal slot array distributed evenly along the middle of its side wall is presented. The reconfigurable feature of the slots is achieved by placing a diode switch across each slot. An integrated bias scheme is introduced for the diode switches to activate and disable the slots. By properly selecting the dimensions for the cavity and the number of activated slots, the optimum values for the gain and front-to-back ratio (FBR) of the antenna can be obtained. The gain value is further increased by adding a skirt-like structure to both the top and bottom of the cavity. A design example is presented with the operating frequency set at 5.8 GHz. The conformal array comprises 24 slots to provide a 15° resolution for main beam switching. The simulation results indicate that the design can offer an antenna gain up to 8.62 dBi and a FBR above 10 dB. These results and the corresponding radiation patterns have gone through experimental verification, from which good agreement is observed.

A wideband pattern-reconfigurable cone antenna employing liquid-metal reflectors is presented. The proposed pattern-reconfigurable antenna consists of a metal cone as the main radiators and eight poles as reflectors for beam switching. It is simple in design and has a wide impedance bandwidth. By changing the states of poles, beam steering can be achieved, where the effect of reflection mechanism is theoretically researched and experimentally validated. Simulated and measured results are found in good agreement with each other. A prototype antenna with four radiation modes is fabricated, which can perform 21 kinds of beam steering over a 360° coverage. It has a fractional bandwidth of 45.5% covering from 1.7 to 2.7 GHz.

For modern directional communication networks, there is a significant and growing need for advanced antenna array designs that combine the high gain and broadband performance together with the low-cost and lightweight characteristics. In this letter, the beam-switching characteristics of a new 4 × 8 right-hand circularly polarized long slot antenna (LSA) array were analyzed when fed by an 8 × 8 Butler matrix. The radiation characteristics were analyzed in terms of bandwidth, beamwidth, gain, cross polarization (x-pol), and axial ratio. Stable radiation patterns were obtained when the main beam directions were within the ±30° angle. The beam-switching LSA array has measured gain of 13.5 dBic and beamwidth of 15° with x-pol greater than 10 dB and axial ratio less than 6 dB. Comparative results with a 4 × 8 stacked patch antenna array are also included for reference.

In this paper, the design of a printed RGW crossover for mm-wave beam switching network is proposed. The proposed device can be considered a good candidate in the design of beam switching network as it has a low loss with a wide bandwidth. The simulated results of the proposed crossover show a 13% fractional bandwidth centered at 30 GHz with an impedance matching level less than −20 dB and isolation level less than −15 dB. In addition, the proposed design has an average transmission loss of 0.5 dB over the operating frequency band.

mm-Wave radars are widely used in the automotive industry, but the concept is rather new for wearable applications, such as detection of obstacles for visually impaired people. Beam-switching techniques for radar antennas, typically, are either complicated or bulky, whereas for wearable applications, simpler methods are desirable. In this paper, we present a high gain antenna array with a low profile and a simple beam-switching design. The concepts of parasitic antenna array and partially reflective surface have been combined to simultaneously achieve a narrow beam (higher gain) as well as beam-switching. Additive manufacturing (screen printing) has been utilized which ensures flexibility (essential for wearable applications) and a lower cost. A ±30° beam switching and 11-13 dB realized gain has been achieved, which is deemed suitable for the given application.

This paper presents a low-cost architecture that allows for beamforming with antenna arrays installed onto unmanned aerial vehicles (UAVs). Beam switching is proposed to improve the antenna gain towards the ground station with two three-element arrays installed below the wings of the UAV. The electromagnetic modeling of the complete structure (UAV and integrated antennas) was performed with commercial electromagnetic simulator Ansys HFSS. The radiation patterns were synthesized with particle swarm optimization (PSO). By employing lumped surface-mount device (SMD) components and switches, the design of the feeder to deliver proper excitation coefficients to the antennas is presented, and its performance was assessed by simulations. The proposed approach is demonstrated to be very effective with low-cost production.

Collaborative beamforming (CB) enables uplink transmission in a wireless sensor network (WSN) composed of sensors (nodes) and far-away access points (APs). It can also be applied to the case where the sensors are equipped with beam-switching structures (BSSs). However, as the antenna arrays of the BSSs are randomly headed due to the irregular mounting surface, some sensors form beams that do not illuminate a desired AP and waste their limited energy. Therefore, to resolve this problem, it is required to switch the beams toward the desired AP. While an exhaustive search can provide the globally optimal combination, a greedy search (GS) is utilized to solve this optimization problem efficiently. Simulation and experimental results verify that under certain conditions the proposed algorithm can drive the sensors to switch their beams properly and increase the received signal-to-noise ratio (SNR) significantly with low computational complexity and energy consumption.

This paper presents the measured results of a $64\mathrm{x}64-$ -way one-body two-dimensional beam-switching Butler matrix using hollow waveguide structure at 19.55 GHz. The one-body two-dimensional switching matrix is realized by introducing the waveguide short-slot 2-plane couplers as hybrid and cross junctions. The 64 beams can cover 39.5% hemisphere by 0.65-wavelength aperture spacing in simulation. The measured beam coverage is almost the same to the simulated one.

We report on a public field trial demonstrating seamless handover in a multi Radio Access Technology mobile network supporting WiFi, LTE, and new 5G radio access in the 60 GHz band for full-duplex enhanced mobile broadband and 5G broadcast hotspots.

A waveguide short-slot two-plane coupler is proposed as a component of 2-D beam-switching Butler matrix. The hybrid and cross coupler operations are designed by including the 2-D polarity symmetry, the propagation constant, and the coupling with the ports of the modes in the coupled region. Their designs are confirmed by experiments. The achieved bandwidth is approximately 2%, restricted by the frequency characteristic of the modes in the coupled region. Since the short-slot two-plane hybrid coupler itself acts as the 2 $\times$ 2-way 2-D beam-switching Butler matrix, the beam switching is also verified by measurements. The general configuration of the 2-D beam-switching Butler matrix is also proposed by using the short-slot two-plane couplers.

The fifth generation (5G) wireless communications systems have brought a growing need for various antennas, electrically small and large, low-gain and large-gain, also at millimeter wavelengths, and in many cases with beam steering or switching capability. Frequencies of 28 GHz, 38 GHz, 58 GHz, 60 GHz, 71–86 GHz, 140–150 GHz, and some even higher window frequencies are of interest in 5G and subsequent generations. Different parts of the systems need different kinds of antennas. In this presentation, we discuss two antenna types that we have recently studied, namely high-gain lenses with beam switching capability and lower gain printed antennas that suit very well for mass production.

Massive multi-input multi-output (MIMO) improves networks throughput via using plenty of antennas at the base station (BS) to serve multiuser simultaneously. Considering channel hardening, we directly investigate the approximate expressions for network throughput with conjugate beamforming (CBF) and zero-forcing beamforming (ZFBF) schemes and adaptive downtilts of antenna patterns. Building on this, a new adaptive beam switching tilting strategy based on the greedy algorithm which adopts the optimal downtilts to serve different regions are proposed to enhance the performance. We also study intercell interference and propose a new modified cooperative approach to reduce interference. Simulation results demonstrate that the system throughput has been improved compared with the traditional method.

This paper presents a design of switched beam antenna using parasitic elements for back lobe reduction to reduce interference signals coming from back side. A single circular patch is used to switch main beam pattern. Beam switching is controlled by shorted and open circuit at the edges of the patch while back lobe is reduced by shorted and open circuit at the parasitic elements. There are eight difference directions of beam switching. The maximum gain of the proposed antenna is 7.62 dBi and maximum back lobe reduction is 4.28 dB when parasitic elements are used.

More than half of the mobile backhaul connections are wireless and huge capacity promise of mmW bands is compelling to cope with the increasing data capacity for future 5G system. We reported a backhaul E-band measurement campaign focusing on radio system measurements with the demonstrator developed in the project. The evaluations include the throughput measurement with different modulation coding scheme and hop length in LOS scenario and the link performance in the light obstructed LOS. It is reported that 1 Gbit/s could be supported up to 300 m, and a reliable transmission was possible up to 400 m at the minimum throughput. The accuracy of beam alignment has been evaluated and it could be improved with the help of electrical beam switching function.

In the machine to machine (M2M) propagation environment, beam direction changing technique for small antenna like dipole antenna size is required. We proposed to adopt meta-surface to achieve this instead of reflectarray. However, study of beam switching for meta-surface is not enough despite of important for mobile M2M. To address the issue, this paper proposes novel reflected beam switching method using meta-surface loaded with active elements.

A high-gain beam switching antenna based on frequency selective surfaces (FSS) operating at 5.2 GHz is presented. In this design, a monopole is used as radiating source and surrounded by four columns of FSS screens and four metallic sheets. The FSS unit cell comprises two metallic crosses and a pin diode embedded between them. The transmission characteristics of the FSS unit cell are investigated when the state of the pin diode is ON and OFF. By changing the states of the pin diodes in the FSS screens, beam switching can be achieved at 5.2 GHz. The metallic sheets are used to improve the gain of the antenna. Simulation results show the gain of the beam switching antenna with metallic sheets has been enhanced 7.2 dB compared to that without metallic sheets.

In this paper a dual polarized aperture-coupled reflectarray unit cell is designed, fabricated, and tested. The element is based on patches aperture-coupled to delay lines. This unit cell has the capability of switching the beam direction in two orthogonal polarizations using a PIN diode or MEMS switch by changing the length of the transmission line coupled to the patch. The proposed structure is used in the design of an X-band reflectarray antenna in two states having angles off broadside of 0$^{\circ}$ and 10$^{\circ}$.

Beam alignment for millimeter wave (mm Wave) vehicular communications is challenging due to the high mobility of vehicles. Recent studies have proposed some beam switching techniques at Road Side Unit (RSU) for vehicle to infrastructure (V2I) communications, employing initial position and speed information of vehicles, that are sent through Dedicated Short Range Communications (DSRC) to the RSU. However, inaccuracies of the provided information lead to beam misalignment. Some beam design parameters are suggested in the literature to combat this effect. But how these parameters should be tuned? Here, we evaluate the effect of all these parameters, and propose a beam design efficiency metric to perform beam alignment in the presence of the estimation errors, and to improve the performance by choosing the right design parameters., Comment: 6 pages, 7 figures, accepted to be published in iccke 2017

In this work, an electronically beam switching device using Rotman lens for mm wave technology at 60 GHz is proposed. The antenna elements are fed by a Rotman lens with five input ports and seven output ports. Rotman lens is a very good candidate as beam forming network due to its compact and planar structure. Five different scanning angels can be accomplished by this design: −30 °, −15°, 0°, +15° and +30 °. The simulation results show good return loss and true time delay performance. The proposed design can be implemented as printed lens-fed multi-beam arrays.

A novel approach to design a wideband 4×4 Butler matrix with a circular polarization is presented. The proposed matrix has the interesting property of avoiding crossings which allows having the entire design over a single substrate layer. The proposed switched beam antenna system is composed of a Butler matrix network and four wideband circular polarization monopole antennas. The performance of the system in terms of beam switching, bandwidth and Axial Ratio (AR) has been simulated using CST Microwave Studio. The obtained results show an impedance bandwidth of 2.3 GHz spanning from 4.2 to 6.5 GHz and an axial ratio (AR) bandwidth of 1.2 GHz spanning from 5.2 to 6.4 GHz.

A low power, small form-factor, 60-GHz radio with beam switching capability is presented. The 3mm×3mm radio IC in 32nm SOI CMOS includes the TX and RX RF front ends, mixers, basebands, PLL and LO chains. The package comprises 2 TX antennas and 2 RX antennas producing low directivity beams in two orthogonal directions to maximize spatial coverage, with an achieved angular coverage of 254°. In board level measurements of the half duplex packaged radio, 17.1dBm EIRP and 6.1dB noise figure are achieved, with power consumption below 250mW.

Beam alignment is a source of overhead in mobile millimeter wave communication systems due to the need for frequent repointing. Beam switching architectures can reduce the amount of repointing required by leveraging position prediction. This paper presents an optimization of beam design in terms of rate. We consider a non-congested two-lane highway scenario where road side units are installed on lighting poles. Under this scenario, line-of-sight to the road side unit is very likely and vehicle speed does not vary much. We formulate and solve numerically using a gradient descent method for an optimal beam design to maximize the data rate for non-overlap beams. The result shows close performance to the equal coverage beam design. We study the effect of the overlap on the average rate and outage and compare the equal coverage with the equal beamwidth design. Numerical examples show that the equal coverage design can achieve up to 1.5x the rate of the equal beamwidth design confirming the importance of the choice of beam design.

In this letter, the design and measurement results of a millimeter-wave beam switching antenna are presented. Several antenna prototypes have been fabricated and measured in planar and conformal installations. The developed prototype consists of three antenna arrays of 16 patch elements in each array and it is operating at 61 GHz with linear polarization. A single-pole three-throw semiconductor switch is attached to the manufactured prototype using copper pillar attachment. The main beam direction of the convex antenna can be changed by switching between the antenna arrays in the prototype. Half sphere 3-D radiation pattern measurements have been performed. For the convex prototype, bent on the cylinder with radius 25 mm, beam switching with ${-{\hbox {32}}^\circ / + {\hbox {34}}^\circ} $ degrees is achieved.

International audience; The purpose of this paper is to report on two microstrip reconfigurable antennas in millimeter wave ranges. The first one has radiation pattern diversity and the second one has directivity diversity. To that effect, two solutions are presented here based on 4-element array. For these two diversities, the main difficulty is to keep up good matching (S11) for all configurations. The design method to respect this parameter will be reviewed. Great results have been achieved with passive prototypes and an unconventional method is given to guarantee matching for each configuration. antennas design procedure is outlined and, finally, results and measurements concerning the two passives prototypes are reviewed.