DOCSLIB.ORG

Integrated Optical Phased Arrays for Beam Forming and Steering

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Integrated Optical Phased Arrays for Beam Forming and Steering applied sciences Review Integrated Optical Phased Arrays for Beam Forming and Steering Yongjun Guo 1,2, Yuhao Guo 1,2, Chunshu Li 1,2, Hao Zhang 1,2, Xiaoyan Zhou 1,2 and Lin Zhang 1,2,* 1 Key Laboratory of Opto-Electronics Information Technology of Ministry of Education, School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China; [email protected] (Y.G.); [email protected] (Y.G.); [email protected] (C.L.); [email protected] (H.Z.); [email protected] (X.Z.) 2 Key Laboratory of Integrated Opto-Electronic Technologies and Devices in Tianjin, School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China * Correspondence: [email protected] Abstract: Integrated optical phased arrays can be used for beam shaping and steering with a small footprint, lightweight, high mechanical stability, low price, and high-yield, benefiting from the mature CMOS-compatible fabrication. This paper reviews the development of integrated optical phased arrays in recent years. The principles, building blocks, and configurations of integrated optical phased arrays for beam forming and steering are presented. Various material platforms can be used to build integrated optical phased arrays, e.g., silicon photonics platforms, III/V platforms, and III–V/silicon hybrid platforms. Integrated optical phased arrays can be implemented in the visible, near-infrared, and mid-infrared spectral ranges. The main performance parameters, such as field of view, beamwidth, sidelobe suppression, modulation speed, power consumption, scalability, and so on, are discussed in detail. Some of the typical applications of integrated optical phased arrays, such as free-space communication, light detection and ranging, imaging, and biological sensing, are shown, with future perspectives provided at the end. Citation: Guo, Y.; Guo, Y.; Li, C.; Zhang, H.; Zhou, X.; Zhang, L. Keywords: integrated; optical phased arrays; beam shaping; beam steering Integrated Optical Phased Arrays for Beam Forming and Steering. Appl. Sci. 2021, 11, 4017. https://doi.org/ 10.3390/app11094017 1. Introduction Academic Editor: In recent years, optical phased arrays (OPAs) have attracted a great deal of attention. Ruediger Grunwald At optical wavelengths, small diffraction angles for a given aperture size can be achieved, compared with microwave radar systems. Featured by precise and agile free-space beam Received: 25 December 2020 forming and steering [1–12], OPA techniques are highly desirable. However, current Accepted: 16 April 2021 commercially available OPA components are mainly based on mechanical control, such as Published: 28 April 2021 motor-driven rotating collimation stages/mirrors. Mechanical beam steering provides high efficiency and a relatively large scanning angle, through mechanically moving parts such Publisher’s Note: MDPI stays neutral as a gimbal, which can be susceptible to mechanical wear and tear, less stable, and limited with regard to jurisdictional claims in in speed [13,14] due to the masses involved. The bulky mechanical steering approach is published maps and institutional affil- less preferred as it typically degrades in performance due to acceleration, temperature, iations. vibration, and inertial forces. Additionally, mechanical steering often consumes significant energy. Furthermore, they require a complex assembly and calibration process, causing a greatly high unit cost. More importantly, these mechanical approaches are only capable of steering a single light beam. Arbitrary pointing and rapid steering as needed for advanced Copyright: © 2021 by the authors. communication and sensing applications then become difficult or even incapable [14–19]. Licensee MDPI, Basel, Switzerland. Optical beam forming and steering have been demonstrated with minimum mechani- This article is an open access article cal movements or completely solid-state OPAs, and the seminal concept was demonstrated distributed under the terms and by a 46-channel lithium tantalate phase modulator for one-dimensional (1D) optical beam conditions of the Creative Commons steering [20]. Existing techniques mainly include liquid crystal (LC) OPAs [21–27], micro- Attribution (CC BY) license (https:// electromechanical system (MEMS) OPAs [28–31], optical fiber phased arrays [32], III–V creativecommons.org/licenses/by/ laser arrays [33], and photonic crystal waveguides with diffraction gratings [34]. 4.0/). Appl. Sci. 2021, 11, 4017. https://doi.org/10.3390/app11094017 https://www.mdpi.com/journal/applsci Appl. Sci. 2021, 11, x FOR PEER REVIEW 2 of 42 Appl. Sci. 2021, 11, 4017 27], microelectromechanical system (MEMS) OPAs [28–31], optical fiber phased arrays2 of 41 [32], III–V laser arrays [33], and photonic crystal waveguides with diffraction gratings [34]. LCLC OPAs OPAs are are the the main main OPA OPA technology technology and and take take advantage advantage of high of high birefringence. birefringence. In theseIn these systems, systems, the orientations the orientations of liquid of liquid crystals crystals induce induce a change a change in the in refractive the refractive index. in- Theydex. thus They act thus as a actprogrammable as a programmable lens that lens can thatsteer can the steerlight theat will. light Although at will. Althoughthe OPA basedthe OPA on cascaded based on liquid cascaded crystal liquid has crystala large hasfield a of large view field (FOV) of view and low (FOV) driving and lowvoltage driv- [19],ing it voltage has a limited [19], it hasoperatio a limitedn speed operation due to the speed time due needed to the for time molecular needed reorientation for molecular [6,14,19,35,36]reorientation [(typically6,14,19,35 ,a36 few] (typically milliseconds a few response milliseconds time response [6,9,18]). time MEMS [6,9 ,18technology]). MEMS typicallytechnology suffers typically from the suffers same from drawback the same [13, drawback36] with tuning [13,36] speeds with tuning typically speeds in millisec- typically ondsin milliseconds [18,37]. Additionally, [18,37]. Additionally, the limited the FOV limited [29,30,37] FOV [29is ,another30,37] is anotherdrawback drawback due to the due multi-wavelengthto the multi-wavelength sizes of sizes elements, of elements, which whichgives rise gives to risegrating to grating lobes in lobes the infar-field the far-field pat- ternspatterns [37]. [37]. Additionally,Additionally, tunable tunable dielectric dielectric metasurfaces metasurfaces modulated modulated by by liquid liquid crystals crystals provide provide opportunitiesopportunities to to develop develop the the next next generation generation light light detection detection and and ranging ranging (LiDAR) (LiDAR) and and displaydisplay technologies. technologies. A A metasurface-based metasurface-based tran transmissivesmissive spatial spatial light light modulator modulator generates generates activeactive beam beam steering steering with with >35% >35% efficiency efficiency and and a alarge large beam beam deflection deflection angle angle of of 11° 11◦ [38].[38]. A A CMOS-compatibleCMOS-compatible all-dielectric all-dielectric silicon silicon (Si)-bas (Si)-baseded metasurface metasurface enabled enabled beam beam steering steering with with highhigh transmission transmission for for wavelengths wavelengths ranging fromfrom 2.962.96 toto 3.215 3.215µ µm.m. Different Different steering steering angles an- glescan can be achievedbe achieved by changingby changing the th periodicitye periodicity of the of the structure structure [39]. [39]. AsAs one one of of the the promising promising solutions solutions for for th thee next-generation next-generation dynamic dynamic beam beam steering, steering, integratedintegrated OPAs OPAs simultaneously simultaneously possess thethe advantagesadvantages ofof being being stable, stable, rapid, rapid, and and precise pre- cisewithout without relying relying on any on mechanicalany mechanical motion, moti makingon, making them robustthem robust and insensitive and insensitive to external to externalconstraints constraints such as accelerations.such as accelerations. Some of theSome integrated of the integrated OPAs are OPAs presented are presented in Figure1 .Ain Figurewire-bonded 1. A wire-bonded device on adevice chip carrier on a chip plugged carrier into plugged a breadboard into a breadboard is presented is in presentedFigure1a. inFigure Figure1b 1a. shows Figure a one-dimensional 1b shows a one-dimensional 64-channel chip-scale 64-channel blue chip-scale light phased blue array.light phased A kind array.of III-V/Si A kind phase-shifter-based of III-V/Si phase-shifter-based OPA is shown OPA in is Figure shown1c. in Figure Figure1 d1c. is Figure the photo 1d is of the a photofabricated of a fabricated OPA chip OPA on a chip penny. on a Using penny. an Using integrated an integrated approach, approach, the OPAs the can OPAs be made can bevery made small. very small. (a) (b) (c) (d) Figure 1. Integrated OPAs. (a) The wire-bonded device on the chip carrier plugged into the breadboard. Reprinted with Figure 1. Integrated OPAs. (a) The wire-bonded device on the chip carrier plugged into the breadboard. Reprinted with permission from [40] © The Optical Society. (b) Blue light OPA. Reprinted with permission from [41] © The Optical Society. permission from [40] © The Optical Society. (b) Blue light OPA. Reprinted with permission from [41] © The Optical Society. (c) A set of three 32-channel and one 240-channel OPAs on a coin. Reprinted with permission
Load more

Recommended publications
  • Agile 3-D Beam-Steering for 60 Ghz Wireless Networks Anfu Zhou∗, Leilei Wu∗, Shaoqing Xu∗, Huadong Ma∗, Teng Wei†, Xinyu Zhang‡ ∗ Beijing Key Lab of Intell
    Following the Shadow: Agile 3-D Beam-Steering for 60 GHz Wireless Networks Anfu Zhou∗, Leilei Wu∗, Shaoqing Xu∗, Huadong Ma∗, Teng Weiy, Xinyu Zhangz ∗ Beijing Key Lab of Intell. Telecomm. Software and Multimedia, Beijing University of Posts and Telecomm. y Department of Electrical and Computer Engineering, University of Wisconsin-Madison z Department of Electrical and Computer Engineering, University of California San Diego Email: fzhouanfu,layla,donggua,[email protected], [email protected], [email protected] Abstract—60 GHz networks, with multi-Gbps bitrate, are Much effort has been devoted to design agile beam-steering, considered as the enabling technology for emerging applications from the hierarchical beam scanning defined in standards [1], such as wireless Virtual Reality (VR) and 4K/8K real-time [9], to heuristic-based shortcuts [10], [11] or sensing-inspired Miracast. However, user motion, and even orientation change, can cause mis-alignment between 60 GHz transceivers’ directional solutions [12], [13]. However, these methods mainly focus on beams, thus causing severe link outage. Within the practical 3D two dimensional (2D) beam-steering, e.g., assuming a phased- spaces, the combination of location and orientation dynamics array that can steer the main beam among different angles leads to exponential growth of beam searching complexity, which within a 2D plane. In practice, the users and radios move in 3D substantially exacerbates the outage and hinders fast recovery. space; and a 60 GHz array can comprise a planar “matrix” of In this paper, we first conduct an extensive measurement to analyze the impact of 3D motion on 60 GHz link performance, antenna elements, steering the beams towards different angles in the context of VR and Miracast applications.
    [Show full text]
  • Planar Pattern Reconfigurable Antenna Integrated with a Wifi System for Multipath Mitigation and Sustained High Definition Video
    Planar Pattern Reconfigurable Antenna Integrated With a WiFi System for Multipath Mitigation and Sustained High Definition Video Networking in a Complex EM Environment Amit Mehta1, Shivam Gautam1, Hasanga Goonesinghe1, Arpan Pal1, Rob Lewis2 and Nathan Clow3 1College of Engineering, Swansea University, Swansea, U.K. [email protected] 2BAE Systems, Chelmsford, UK 3DSTL, Fort Halstead, UK Abstract—A planer pattern reconfigurable square loop antenna integrated in a complete wireless system is presented. II. ANTENNA CONFIGURATION The antenna is designed to operate at 5 GHz WiFi band of Fig. 1 shows the top and side view of the SLA designed IEEE 802.11 ac. The antenna under electronic switching for 5 GHz WiFi band. The Antenna structure is inspired generates four tilted beams in the four space quadrants. These four beams are moved intelligently and automatically in space from [4]. The SLA has four conducting arms, each of length using a C# program for achieving and sustaining maximum 32 mm and a track width of 1.5 mm. The square loop is possible throughput. This auto beam steering is advantageous etched on top of a Rogers 4350B (ɛr=3.66, tanδ=0.009) for scenarios where a mobile user suffers from multipath substrate having a thickness of 9.6 mm and an area of 60 fading in a complex electromagnetic environment. mm × 60 mm. The entire structure is backed by a metal ground plane. The SLA is excited at the center point of each I. INTRODUCTION arm (A, B, C and D) by four vertical probes of diameter 1.3 Indoor wireless communication in 5 the GHz WiFi band of mm which are connected to the four SMA ports (A0, B0, C0 IEEE 802.11 ac is becoming popular today due to the and D0) at the bottom of the antenna.
    [Show full text]
  • Error Analysis of Programmable Metasurfaces for Beam Steering Hamidreza Taghvaee, Albert Cabellos-Aparicio, Julius Georgiou, and Sergi Abadal
    1 Error Analysis of Programmable Metasurfaces for Beam Steering Hamidreza Taghvaee, Albert Cabellos-Aparicio, Julius Georgiou, and Sergi Abadal Abstract—Recent years have seen the emergence of pro- global or local reconfigurability [16]. Further, recent years grammable metasurfaces, where the user can modify the EM re- have seen the emergence of programmable metasurfaces, this sponse of the device via software. Adding reconfigurability to the is, metasurfaces that incorporate local tunability and digital already powerful EM capabilities of metasurfaces opens the door to novel cyber-physical systems with exciting applications in do- logic to easily reconfigure the EM behavior from the outside. mains such as holography, cloaking, or wireless communications. Two main approaches have been proposed for the im- This paradigm shift, however, comes with a non-trivial increase of plementation of programmable metasurfaces, namely, (i) by the complexity of the metasurfaces that will pose new reliability interfacing the tunable elements through an external Field- challenges stemming from the need to integrate tuning, control, Programmable Gate Array (FPGA) [17], [18], or (ii) by and communication resources to implement the programmability. While metasurfaces will become prone to failures, little is known integrating sensors, control units, and actuators within the about their tolerance to errors. To bridge this gap, this paper metasurface structure [19]–[22]. examines the reliability problem in programmable metamaterials Programmable metasurfaces have opened the door to dis- by proposing an error model and a general methodology for error ruptive paradigms such as Software-Defined Metamaterials analysis. To derive the error model, the causes and potential (SDMs) and Reconfigurable Intelligent Surfaces (RISs), lead- impact of faults are identified and discussed qualitatively.
    [Show full text]
  • A Design Approach of Optical Phased Array with Low Side Lobe Level and Wide Angle Steering Range
    hv photonics Article A Design Approach of Optical Phased Array with Low Side Lobe Level and Wide Angle Steering Range Xinyu He, Tao Dong *, Jingwen He and Yue Xu State Key Laboratory of Space-Ground Integrated Information Technology, Beijing Institute of Satellite Information Engineering, Beijing 100095, China; [email protected] (X.H.); [email protected] (J.H.); [email protected] (Y.X.) * Correspondence: [email protected] Abstract: In this paper, a new design approach of optical phased array (OPA) with low side lobe level (SLL) and wide angle steering range is proposed. This approach consists of two steps. Firstly, a nonuniform antenna array is designed by optimizing the antenna spacing distribution with particle swarm optimization (PSO). Secondly, on the basis of the optimized antenna spacing distribution, PSO is further used to optimize the phase distribution of the optical antennas when the beam steers for realizing lower SLL. Based on the approach we mentioned, we design a nonuniform OPA which has 1024 optical antennas to achieve the steering range of ±60◦. When the beam steering angle is 0◦, 20◦, 30◦, 45◦ and 60◦, the SLL obtained by optimizing phase distribution is −21.35, −18.79, −17.91, −18.46 and −18.51 dB, respectively. This kind of OPA with low SLL and wide angle steering range has broad application prospects in laser communication and lidar system. Keywords: optical phased array; antenna array; low side lobe; wide angle steering range 1. Introduction Citation: He, X.; Dong, T.; He, J.; Xu, Optical phased array (OPA) is an array operating at optical frequency that achieves Y.
    [Show full text]
  • Mm-Wave Beam Steering Without In-Band Measurement
    Steering with Eyes Closed: mm-Wave Beam Steering without In-Band Measurement Thomas Nitscheyz, Adriana B. Flores∗, Edward W. Knightly∗, and Joerg Widmery yIMDEA Networks Institute, Madrid, Spain ∗ECE Department, Rice University, Houston, USA zUniv. Carlos III, Madrid, Spain Abstract—Millimeter-wave communication achieves multi- found that a mere misalignment of 18 degree reduces the link Gbps data rates via highly directional beamforming to overcome budget by around 17 dB. According to IEEE 802.11ad coding pathloss and provide the desired SNR. Unfortunately, establishing sensitivities [3], this drop can reduce the maximum throughput communication with sufficiently narrow beamwidth to obtain the necessary link budget is a high overhead procedure in which by up to 6 Gbps or break the link entirely. This misalignment is the search space scales with device mobility and the product of easily reached multiple times per second by a user holding the the sender-receiver beam resolution. In this paper, we design, device, causing substantial beam training overhead to enable implement, and experimentally evaluate Blind Beam Steering multi-Gbps throughput for mm-Wave WiFi. (BBS) a novel architecture and algorithm that removes in-band In this paper, we design, implement, and experimentally overhead for directional mm-Wave link establishment. Our sys- tem architecture couples mm-Wave and legacy 2.4/5 GHz bands evaluate Blind Beam Steering (BBS), a system to steer mm- using out-of-band direction inference to establish (overhead-free) Wave beams by replacing in-band trial-and-error testing of multi-Gbps mm-Wave communication. Further, BBS evaluates virtual sector pairs with “blind” out-of-band direction acqui- direction estimates retrieved from passively overheard 2.4/5 GHz sition.
    [Show full text]
  • High Planar Arrays and Array Feeds for Satellite Communications
    High Efficiency Planar Arrays and Array Feeds for Satellite Communications Zhenchao Yang, Kyle Browning, and Karl Warnick Department of Electrical and Computer Engineering Brigham Young University, Provo, Utah, USA [email protected], [email protected] Abstract—Limited scan range beamsteering can serve as a mechanical steered dishes. From a technical point of view, cost-effective solution for three application scenarios in satellite precisely beam steering in limited scan range plus coarse communications. Two feasible technical paths to realize the mechanical steering opens the third option for full beam steer- function are discussed in this paper. The first one is to utilize a electronically steered array feed with a conventional parabolic ing with potential lower cost and higher tracking speed and reflector. By feeding the reflector with different weights across accuracy than current barely mechanical steering, particularly the array feed, the phase distribution on the dish aperture is for multi-feed systems. There are also three common scenarios continuously shifted leading to a steered beam. Acquisition and that conventional fixed-mount dishes can not serve well. First, tracking functions can be realized economically by integrating a current dish installation demands accurate pointing. Lowering power detector based feedback system. A necessary calibration process is provided to ensure a correct indicator of signal- the accuracy requirement would increase the productivity of to-noise ratio. One dimensional bemsteering was demonstrated dish installation. Second, mount degradations caused by sag- experimentally and an improved two dimensional system is shown ging roof and weather disasters require dish re-pointing, which as well. The second path is to use a tile array with each tile costs millions of dollars in the Satcom industry.
    [Show full text]
  • Wideband Beam Steering Concept for Terahertz Time-Domain Spectroscopy: Theoretical Considerations
    sensors Article Wideband Beam Steering Concept for Terahertz Time-Domain Spectroscopy: Theoretical Considerations Xuan Liu *,† , Kevin Kolpatzeck *,† , Lars Häring, Jan C. Balzer and Andreas Czylwik Chair of Communication Systems (NTS), Faculty of Engineering, University of Duisburg-Essen (UDE), 47057 Duisburg, Germany; [email protected] (L.H.); [email protected] (J.C.B.); [email protected] (A.C.) * Correspondence: [email protected] (X.L.); [email protected] (K.K.) † These authors contributed equally to this work. Received: 3 August 2020; Accepted: 26 September 2020; Published: 28 September 2020 Abstract: Photonic true time delay beam steering on the transmitter side of terahertz time-domain spectroscopy (THz TDS) systems requires many wideband variable optical delay elements and an array of coherently driven emitters operating over a huge bandwidth. We propose driving the THz TDS system with a monolithic mode-locked laser diode (MLLD). This allows us to use integrated optical ring resonators (ORRs) whose periodic group delay spectra are aligned with the spectrum of the MLLD as variable optical delay elements. We show by simulation that a tuning range equal to one round-trip time of the MLLD is sufficient for beam steering to any elevation angle and that the loss introduced by the ORR is less than 0.1 dB. We find that the free spectral ranges (FSRs) of the ORR and the MLLD need to be matched to 0.01% so that the pulse is not significantly broadened by third-order dispersion. Furthermore, the MLLD needs to be frequency-stabilized to about 100 MHz to prevent significant phase errors in the terahertz signal.
    [Show full text]
  • The Development of Phased-Array Radar Technology the Development of Phased-Array Radar Technology
    • FENN, TEMME, DELANEY, AND COURTNEY The Development of Phased-Array Radar Technology The Development of Phased-Array Radar Technology Alan J. Fenn, Donald H. Temme, William P. Delaney, and William E. Courtney I Lincoln Laboratory has been involved in the development of phased-array radar technology since the late 1950s. Radar research activities have included theoretical analysis, application studies, hardware design, device fabrication, and system testing. Early phased-array research was centered on improving the national capability in phased-array radars. The Laboratory has developed several test-bed phased arrays, which have been used to demonstrate and evaluate components, beamforming techniques, calibration, and testing methodologies. The Laboratory has also contributed significantly in the area of phased-array antenna radiating elements, phase-shifter technology, solid-state transmit-and- receive modules, and monolithic microwave integrated circuit (MMIC) technology. A number of developmental phased-array radar systems have resulted from this research, as discussed in other articles in this issue. A wide variety of processing techniques and system components have also been developed. This article provides an overview of more than forty years of this phased-array radar research activity. was certainly affordable array radar with thousands of array ele- not new when Lincoln Laboratory’s phased- ments, all working in tightly orchestrated phase co- Tarray radar development began around 1958. herence, would not be built for a very long time. In Early radio transmitters and the early World War II retrospect, both the enthusiasts and the skeptics were radars used multiple radiating elements to achieve de- right. The dream of electronic beam movement was sired antenna radiation patterns.
    [Show full text]
  • Beam-Forecast: Facilitating Mobile 60 Ghz Networks Via Model-Driven Beam Steering Anfu Zhou∗ Xinyu Zhang† Huadong Ma∗ ∗ Beijing Key Lab of Intell
    IEEE INFOCOM 2017 - IEEE Conference on Computer Communications Beam-forecast: Facilitating Mobile 60 GHz Networks via Model-driven Beam Steering Anfu Zhou∗ Xinyu Zhang† Huadong Ma∗ ∗ Beijing Key Lab of Intell. Telecomm. Software and Multimedia, Beijing University of Posts and Telecomm. † University of Wisconsin-Madison Email: [email protected], [email protected], [email protected] Abstract—Low robustness under mobility is the Achilles’ heel of 60 GHz radios: (i) High directionality. 60 GHz radios of the emerging 60 GHz networking technology. Instead of using face much stronger attenuation than existing Wi-Fi (26dB and omni-directional antennas as in existing Wi-Fi/cellular networks, 21.6dB worse when compared with 2.4 GHz and 5 GHz WiFi, 60 GHz radios communicate via highly-directional links formed by phased-array beam-forming, so as to upgrade wireless link respectively [10]). To remedy such strong attenuation, 60 GHz throughput to multi-Gbps. However, user motion causes misalign- radios employ phased-array antennas to form highly directional ment between the Tx’s and Rx’s beam directions, and often leads beams. But high directionality results in high vulnerability to to link outage. Legacy 60 GHz protocols realign the beams by mobility — whenever the Tx/Rx moves, their beam directions scanning alternative Tx/Rx beams. But unfortunately this tedious may become misaligned, causing high risk of link outage. (ii) process can easily overwhelm the useful channel time, leaving the Tx/Rx in misalignment most of the time during mobility. In this Channel sparsity. As reported widely by existing work [11]– paper, we propose Beam-forecast, a novel model-driven beam [14], the 60 GHz spatial channel profile (SCP) is extremely steering approach that can sustain high performance for mobile sparse, i.e., the Tx can reach the Rx only through a small 60 GHz links.
    [Show full text]
  • Using Steerable Beam Directional Antenna for Vehicular Network Access
    MobiSteer: Using Steerable Beam Directional Antenna for Vehicular Network Access Vishnu Navda1, Anand Prabhu Subramanian1 , Kannan Dhanasekaran1 , Andreas Timm-Giel2, Samir R. Das1 1 Computer Science Department, Stony Brook University, Stony Brook, NY 11794, U.S.A. 2 University of Bremen, TZI, Communication Networks, 28334 Bremen, Germany ABSTRACT In this work, we investigate the use of directional anten- nas and beam steering techniques to improve performance of 802.11 links in the context of communication between a moving vehicle and roadside APs. To this end, we develop a framework called MobiSteer that provides practical ap- proaches to perform beam steering. MobiSteer can operate in two modes { cached mode { where it uses prior radio survey data collected during \idle" drives, and online mode, where it uses probing. The goal is to select the best AP and beam combination at each point along the drive given the available information, so that the throughput can be maxi- mized. For the cached mode, an optimal algorithm for AP and beam selection is developed that factors in all overheads. We provide extensive experimental results using a com- mercially available eight element phased-array antenna. In the experiments, we use controlled scenarios with our own APs, in two different multipath environments, as well as in Figure 1: Beam steering and AP selection to im- situ scenarios, where we use APs already deployed in an ur- prove connectivity. ban region { to demonstrate the performance advantage of using MobiSteer over using an equivalent omni-directional antenna. We show that MobiSteer improves the connec- Keywords tivity duration as well as PHY-layer data rate due to bet- Steerable Beam, Phased-array Antenna, Vehicular Internet ter SNR provisioning.
    [Show full text]
  • Antenna Beam Steering and Beam Forming at Mm-Wave and Thz Frequencies
    Antenna beam steering and beam forming at mm-Wave and THz frequencies Master Thesis submitted to the Faculty of the Escola T`ecnicad'Enginyeria de Telecomunicaci´ode Barcelona Universitat Polit`ecnicade Catalunya by Sara Vega Pi~na In partial fulfillment of the requirements for the master in TELECOMMUNICATIONS ENGINEERING Advisor: Mar´ıaConcepci´onSantos Co-Advisor: Daniel Nu~no Barcelona, January 20th, 2021 Contents List of Figures4 List of Tables6 1 Introduction8 2 Photonic Antenna Control 10 2.1 Phased Array Antennas Beam forming...................... 10 2.2 Photoconductive Antennas for THz Radiation.................. 11 3 Optical TTD Network 14 3.1 Multiwavelength Beam Steering Network.................... 14 3.1.1 Effect of compensating delays...................... 15 3.1.2 Geometrical Delays............................ 16 3.1.3 Dispersive Delays............................ 18 3.1.4 Maximum beam steered angle...................... 19 3.2 CD-fading control................................. 20 3.3 OTTDN Simulations............................... 23 4 TeraHertz Systems 26 4.1 Definition of THz systems simulation methodology............... 26 4.1.1 Time-Domain simulation of PCAs (Primary fields)........... 26 4.1.2 Time-Domain simulation of Lens-coupled PCAs (Secondary fields).. 32 4.2 Validation of THz Simulation Methodology................... 35 4.2.1 PCAs modeling.............................. 35 4.2.2 Lens approach.............................. 36 4.2.3 Primary fields............................... 38 4.2.4 Secondary fields............................. 38 4.3 Simulation and measurement of THz systems.................. 40 4.3.1 Fractal structures characteristics..................... 40 4.3.2 Modeling of Sierpinski Fractal structures for THz radiation....... 40 4.3.3 Simulation of THz Far Fields with Sierpinski structures......... 44 4.4 Terahertz Beam Steering............................. 49 5 Conclusions and future development 52 References 54 Appendices 59 A Matlab Codes 59 A.1 VPI Radiation Pattern .mat file.........................
    [Show full text]
  • A Novel Millimeter-Wave Dual-Fed Phased Array for Beam Steering
    A Novel Millimeter-Wave Dual-Fed Phased Array for Beam Steering Zur Erlangung des akademischen Grades eines DOKTOR-INGENIEURS von der Fakultat¨ fur¨ Elektrotechnik und Informationstechnik, am Karlsruher Institut fur¨ Technologie (KIT) genehmigte DISSERTATION von M.Sc. Ali Eray Topak geb. in Denizli, Turkei¨ Tag der mundlichen¨ Prufung:¨ 14. November 2013 Hauptreferent: Prof. Dr.-Ing. Thomas Zwick Korreferent: Prof. Dr.-Ing. Christian Waldschmidt Abstract A phased array antenna, used for shaping and steering the main antenna beam electronically to chosen directions within the predefined field of view, has been the key antenna system for satellite communications and military radars for decades. However, despite its high functional performance, it is still a very costly and complex solution for emerging wireless consumer applications such as high speed wireless communication and driving assistance systems due to the number of phase shifters and their complex control circuitry. Even more challenges are encountered with an increase in the number of channels if an antenna with high directivity is desired, such as routing RF and IF circuits, isolation of neighboring RF channels or calibra- tion of a whole system. In order to eliminate the challenges stated above, a novel beam steering approach is presented in this dissertation based on the superposition of two squinted antenna beams. The two an- tenna beams are realized by exciting the opposite feeds of a dual-fed array antenna. A change in the phase difference and amplitude ratio between the input signals, using only one phase shifter and two variable gain amplifiers or only two I-Q vector modulators, steers the main beam in different directions.
    [Show full text]