Showing papers on "Active antenna published in 2019"

Intelligent Reflecting Surface Enhanced Wireless Network via Joint Active and Passive Beamforming

Abstract: Intelligent reflecting surface (IRS) is a revolutionary and transformative technology for achieving spectrum and energy efficient wireless communication cost-effectively in the future. Specifically, an IRS consists of a large number of low-cost passive elements each being able to reflect the incident signal independently with an adjustable phase shift so as to collaboratively achieve three-dimensional (3D) passive beamforming without the need of any transmit radio-frequency (RF) chains. In this paper, we study an IRS-aided single-cell wireless system where one IRS is deployed to assist in the communications between a multi-antenna access point (AP) and multiple single-antenna users. We formulate and solve new problems to minimize the total transmit power at the AP by jointly optimizing the transmit beamforming by active antenna array at the AP and reflect beamforming by passive phase shifters at the IRS, subject to users’ individual signal-to-interference-plus-noise ratio (SINR) constraints. Moreover, we analyze the asymptotic performance of IRS’s passive beamforming with infinitely large number of reflecting elements and compare it to that of the traditional active beamforming/relaying. Simulation results demonstrate that an IRS-aided MIMO system can achieve the same rate performance as a benchmark massive MIMO system without using IRS, but with significantly reduced active antennas/RF chains. We also draw useful insights into optimally deploying IRS in future wireless systems.

Linearity and Efficiency in 5G Transmitters: New Techniques for Analyzing Efficiency, Linearity, and Linearization in a 5G Active Antenna Transmitter Context

Abstract: Every new generation of mobile systems should provide higher capacity, serve more users, be more energy efficient, and have lower cost. Radio-access hardware constitutes a major bottleneck for reaching these goals, which is a particularly noticeable issue now that 5G communication systems are being developed. A combination of breakthroughs in communication theory-as in massive multiple input/multiple output (MIMO) [1], highly integrated semiconductor and packaging technologies, and extended spectrum allocations- has enabled a paradigm shift in the way radio hardware will be realized. Today's high-power, fewantenna, sectorized systems will soon be replaced with highly integrated active antenna systems having up to hundreds of individually driven low-power radios operating with very wideband signals.

Elevation Beamforming With Full Dimension MIMO Architectures in 5G Systems: A Tutorial

Abstract: Full dimension (FD) multiple-input multiple-output (MIMO) technology has attracted substantial research attention from both wireless industry and academia in the last few years as a promising technique for next-generation wireless communication networks. FD-MIMO scenarios utilize a planar 2-D active antenna system (AAS) that not only allows a large number of antenna elements to be placed within feasible base station (BS) form factors, but also provides the ability of adaptive electronic beam control over both the elevation and the traditional azimuth dimensions. This paper presents a tutorial on elevation beamforming analysis for cellular networks utilizing FD massive MIMO antenna arrays. In contrast to existing works that focus on the standardization of FD-MIMO in the 3rd generation partnership project (3GPP), this tutorial is distinguished by its depth with respect to the theoretical aspects of antenna array and 3-D channel modeling. In an attempt to bridge the gap between industry and academia, this preliminary tutorial introduces the relevant array and transceiver architecture designs proposed in the 3GPP Release 13 that enable elevation beamforming. Then it presents and compares two different 3-D channel modeling approaches that can be utilized for the performance analysis of elevation beamforming techniques. The spatial correlation in FD-MIMO arrays is characterized and compared based on both channel modeling approaches and some insights into the impact of different channel and array parameters on the correlation are drawn. All these aspects are put together to provide a mathematical framework for the design of elevation beamforming schemes in single-cell and multi-cell scenarios. Simulation examples associated with comparisons and discussions are also presented. To this end, this paper highlights the state-of-the-art research and points out future research directions.

Synthesis Algorithm for Near-Field Power Pattern Control and Its Experimental Verification via Metasurfaces

Abstract: Antennas and metasurfaces have enabled a number of far-field manipulation functions. According to the addition theorem of multipoles, near fields have richer spatial spectra than far fields; hence, in the near-field region, it is easier to achieve complex manipulations on field distributions. In this paper, an algorithm is presented to synthesize the near fields of source arrays. Given target distributions of near-field intensities and also predefined source magnitudes, the algorithm will find the needed source phases, which can then be applied on active antenna arrays and passive metasurfaces to induce the target distribution of fields. The algorithm adopts the dyadic Green’s function as the propagator, and hence, it naturally takes account of the near-field and vector properties of electromagnetic fields. As a typical application of the algorithm, an example is given to obtain the excitation phases of a dipole array, which is then physically imitated by a coding metasurface. Experimental measurement is performed and the result proves the validity of the algorithm. From the perspective of information metasurface, the algorithm finds the phase-coding pattern of metasurface to achieve specific functions.

A Directly Matched PA-Integrated $K$ -Band Antenna for Efficient mm-Wave High-Power Generation

Abstract: A $K$ -band slot antenna element with an integrated gallium nitride power amplifier (PA) is presented. It has been optimized through a circuit–electromagnetic codesign methodology to directly match the transistor drain output to its optimal load impedance ( $\mathrm{Z_{opt}} = 17+j46\; \Omega$ ), while accounting for the over-the-air coupling effects in the vicinity of the transition between the PA and antenna. This obviates the need for using a potentially lossy and bandwidth-limiting output impedance-matching network. The measured PA-integrated antenna gain of 15 dBi with a 40% total efficiency at 28 dBm output power agrees well with the theoretically achievable performance targets. The proposed element is compact ( $0.6 \times 0.5 \times 0.3\; \lambda ^3$ ) and, thus, well suited to meet the high-performance demands of future emerging beamforming active antenna array applications.

Silicon-Based Embedded Trenches of Active Antennas for High-Responsivity Omnidirectional Photodetection at Telecommunication Wavelengths.

Abstract: Although the use of plasmonic nanostructures for photodetection below the band gap energy of the semiconductor has been intensively investigated recently, efficiencies of such hot electron-based devices have, unfortunately, remained low because of the inevitable energy loss of the hot electrons as they move and transfer in active antennas based on metallic nanostructures. In this work, we demonstrate the concept of high-refractive-index material-embedded trench-like (ETL) active antennas that could be used to achieve almost 100% absorbance within the ultrashallow region (approximately 10 nm) beneath the metal–semiconductor interface, which is a much smaller distance compared with the hot electrons’ mean free path in the noble metal layer. Taking advantage of these ETL-based active antennas, we obtained photoresponsivities under zero bias at wavelengths of 1310 and 1550 nm of 5854 and 693 nA mW–1, respectively—values higher than most those previously reported for active antenna-based silicon (Si) photodete...

Security Enhancing Spatial Modulation Using Antenna Selection and Artificial Noise Cancellation

Abstract: In the multi-input multi-output (MIMO) wireless communication systems, spatial modulation (SM) has wide application prospects as a novel modulation technology. In this paper, a new secrecy enhancement scheme for the SM system is proposed, in which the number of transmit antennas $N_{a}$ is not a power of two. The transmitter first chooses $N_{t}$, which is a power of two, antennas from $N_{a}$ transmit antennas for SM. Then, the transmitter transmits, in addition to the information symbols, an artificial noise (AN) through the active antenna. At the same time, another one of the remaining $N_{a}-N_{t}$ antennas is activated randomly by the transmitter to transmit another AN. The ANs are designed by exploiting the channel state information (CSI) of the legitimate channel, and then the ANs can only be cancelled at the legitimate receiver while the passive eavesdropper will suffer the interference of them. Furthermore, the security performance of the proposed scheme is also analyzed. Numerical results verify that our proposed scheme is able to achieve a satisfactory performance.

UWB Active Antenna for Microwave Breast Imaging Sensing Arrays

Abstract: An ultrawideband (UWB) active slot antenna for tissue sensing arrays is developed and measured to operate from 3 to 8 GHz. The sensing element reported here is to be used in the imaging of the breast. It integrates a low-noise amplifier (LNA) with a printed-slot antenna to achieve gain enhancement of about 20 dB. The first prototype integrates the biasing of the LNA on the same board as the antenna. The second prototype uses an external bias tee providing dc power to the LNA through the coaxial connector of the active antenna. Both prototypes achieve the expected gain enhancement in comparison with the passive antenna element.

Cavity-backed Stacked Patch Array Antenna with Dual Polarization for mmWave 5G Base Stations

Abstract: This paper proposed a dual polarized patch array antenna for millimeter-wave 5G base stations. The antenna operating at 28 GHz band is designed on 12-layer PCB lamination. A stacked patch topology was applied to secure the wide bandwidth of the antenna. In addition, in order to increase the gain of the patch antenna, a substrate-integrated cavity composed of via walls was applied. 8-element antenna array configuration was proposed for active antenna base station with vertical beam steering. Through simulated and measured results, it is determined that the proposed array antenna has good performance suitable for 5G base stations.

EDAS/COAS Based Antenna Selection for Code Index Modulation Aided Spatial Modulation

Abstract: DOI : 10.26650/electrica.2019.19003 In this study, a new code index modulation (CIM) aided spatial modulation (SM) technique based on the Euclidean distance and capacity optimized based antenna selection (EDAS/COAS), called EDAS/COAS-CIM-SM, is proposed for multiple-input multiple output (MIMO) systems. Since in the proposed EDAS/COAS-CIM-SM technique, incoming information data bits indicates modulated symbols, activated transmit antenna indices as well as their corresponding spreading code indices, data bits are conveyed not only by the modulated symbols but also by the indices of the active antenna and spreading code indices. Thus, the proposed two systems provide faster data rates while spending less transmission power and possessing better error performance than the conventional direct sequence- spread spectrum (DS-SS), SM, EDAS and COAS based SM (EDAS-SM, COAS-SM), and CIM based SS (CIM-SS) systems. In addition, in order to improve the overall performance of the CIM aided SM (CIM-SM) system, EDAS and COAS techniques are considered at the receiver. Computer simulations have also shown that the EDAS/COAS-CIM-SM system has better error performance than the CIM-SM system over the Rayleigh fading channels for binary phase shift keying (BPSK) modulation schemes. Cite this article as : Aydin E. EDAS/COAS Based Antenna Selection for Code Index Modulation Aided Spatial Modulation. Electrica 2019; 10.26650/electrica.2019.19003.

PAPR-Limited Precoding in Massive MIMO Systems with Reflect- and Transmit-Array Antennas

Abstract: Conventional hybrid analog-digital architectures for millimeter-wave massive multiple-input multiple-output (MIMO) systems suffer from poor scalability and high implementational costs. The former is caused by the high power loss in the analog network, and the latter is due to the fact that classic MIMO transmission techniques require power amplifiers with high back-offs.This paper proposes a novel hybrid analog-digital architecture which addresses both of these challenges. This architecture implements the analog front-end via a passive reflect- or transmit-array to resolve the scalability issue. To keep the system cost-efficient, a digital precoder is designed whose peak-to-average power ratio (PAPR) on each active antenna is tunable. Using the approximate message passing algorithm, this precoder is implemented with tractable computational complexity. The proposed architecture allows for the use of power amplifiers with low back-offs which reduces the overall radio frequency cost of the system. Numerical results demonstrate that for low PAPRs, significant performance enhancements are achieved compared to the state of the art.

Far-Field-Based Nonlinear Optimization of Millimeter-Wave Active Antenna for 5G Services

Abstract: This paper presents the design and characterization of millimeter-wave (28/38 GHz), circularly polarized (CP) active antennas, suitable for future 5G services. By augmenting the modeling capabilities of commercially available nonlinear CAD tools, the active antenna design can simultaneously optimize figures of merits for both radiation and nonlinear (NL) performance. The radiating part is computed and optimized layoutwise by means of an artificial neural network (ANN), suitably trained off-line. For the NL design purpose, the harmonic neural network (HNN) of the antenna is subsequently implemented as a standard circuit component, to include the antenna behavior at all the harmonics of its NL regime. This allows avoiding time-consuming electromagnetic (EM)-simulations in the harmonic balance optimization loop. In this way, a well-defined interface between the antenna and the amplifier can be avoided. To demonstrate the effectiveness of the design approach, one active integrated antenna (AIA), consisting of a class AB amplifier feeding a CP patch at 38 GHz, has been fabricated with the standard 0.1- $\mu \text{m}$ AlGaAs-InGaAs pHEMT technology and extensively measured with respect to both the electrical and radiation performances. To reduce fabrication costs, hybrid integration of the antenna and amplifier connection is used, and the antenna is incorporated into the main PCB.

A Novel Bandwidth-Enhanced Dual-Polarized Antenna With Symmetrical Closed-Resonant-Slot Pairs

Abstract: A novel bandwidth-enhanced dual-polarized antenna (BEDPA) with symmetrical closed-resonant-slot pairs for 2/3/4G and international mobile telecommunications bands is proposed. The BEDPA is realized by etching closed slots symmetrically on the conventional cross-dipole broadband dual-polarized antenna to increase a new resonant mode in the higher band. As simulation and experiment indicated, the BEDPA obtains an impedance bandwidth of 67.3% (1.4 - 2.82 GHz) for VSWR 38 dB. Over the operating frequency, the BEDPA achieves a stable radiation pattern with a half-power beamwidth (HPBW) within 64.5 ± 4.5°, a gain within 8.9 ± 0.7 dBi, and a cross-polarization discrimination (XPD) > 22 dB. Furthermore, a linear array with an impedance bandwidth of 73.1% (1.37 - 2.95 GHz) and an ISO > 27 dB is fabricated for the active antenna unit application. The linear array achieves a HPBW within 64 ± 6.5°, a gain within 16.5 ± 1.5 dBi, a sidelobe suppression (SLS) > 16 dB, and a front-to-back ratio (F/B) > 24 dB.

A Bond Wire Connection Implementation at mm-Wave Active Microstrip Antenna

Abstract: A bond wire to microstrip line transition, featuring two impedance transformers, is presented for a mm-wave microstrip antenna and power amplifier (PA) integration using conventional bond wires. Simulated return loss bandwidth for the transition is 4 GHz with a minimum insertion loss of 1 dB. Measurement results for the designed active antenna are compared with measurements for a passive antenna and a standalone PA. The maximum gain is 29 dBi, compared with 16.7-dBi passive antenna maximum gain. The half-power gain bandwidth is 7%. The measured active antenna radiation pattern is in good agreement with simulations. The maximum deembedded PA output power is close to 9 dBm.

Joint Design and Co-integration of Antenna-IC Systems

Abstract: An overview of design challenges for beamforming active antenna arrays, which are needed to meet high-performance demands of future emerging applications, is presented. The critical role of antenna element mutual coupling on the receiving system sensitivity of array receivers, and effective radiated power of MIMO-type array transmitters is discussed. Trade-offs, common misconceptions, and practical examples are shown and discussed. Techniques towards strong integration between antennas and LNAs/PAs that blurs the geometrical boundaries between them are presented. This will cover mm-wave antenna design examples, where direct matching of active devices to their optimal source/load impedances eliminates the losses of 50-Ohm impedance matching networks. An antenna-integrated high-efficiency (Doherty) PA, operating at the sub-6 GHz band and utilizing active load modulation, will be taken as an on-antenna power combining example, including optimization aspects and over-the-air characterization.

Remote Diagnosis of Fault Element in Active Phased Arrays using Deep Neural Network

Abstract: It can be extremely mission-critical to identify the source of an error in satellite communication systems and in this initial work an approach based on neural networks is proposed for diagnosing the faulty antenna elements remotely from the receiver side. A simple active antenna array which consists of four power amplifiers and a four-by-one linear antenna array has been considered in this work for proof of concept. Signals captured from various fault scenarios are used to train a 4layered feed-forward neural network using amplitude and phase data. The validation results show that the trained neural network can correctly identify the fault power amplifier with an accuracy higher than 96 %, which indicates the promising potential of the proposed approach.

Multi-chip millimeter-wave interface

Abstract: Systems and methods are provided for millimeter-wave (MMW) communication, the system includes a transceiver chip to generate and to receive signals An interface is used to communicate the signals between the transceiver chip and one or more active antenna modules The signals include modulated MMW signals and control signals The transceiver chip includes baseband circuitry, up and down conversion mixers, and RF front-end circuitry An active antenna module receives a first modulated MMW signal from the interface for transmission via antennas and to receive a second modulated MMW signal from the antennas for transmission through the interface to the transceiver chip

An Active Antenna Subarray for the Low-Frequency Radio Telescope GURT—Part I: Design and Theoretical Model

Abstract: The new Giant Ukrainian Radio Telescope (GURT) intended for operation in 8–80 MHz range is now under construction. It employs an active phased array antenna composed of many dipole subarrays, several of which have been implemented and now are used for radio astronomy observations. In this two-part paper, the electrical and noise parameters of the subarray are studied by numerical and experimental ways. In this part, a theoretical model of the subarray based on the wave theory of noisy multiport networks that takes into account the mutual coupling in the dipole array placed over imperfect ground and the correlation between all existing noise sources is proposed. It is assumed that the initial parameters for this model should be obtained using the correct electromagnetic and circuit simulation. A technique for using of this model to calculate the effective area, radiation efficiency, internal and external noise temperatures, as well as sensitivity of the subarray in terms of system equivalent flux density (SEFD) for all possible beam directions in the frequency band of the GURT radio telescope is described.

Peripherally Excited Phased Arrays: Beam Steering with Reduced Number of Antenna Elements

Abstract: A new concept is proposed for reducing the number of active antenna elements in a scannable phased array. The proposed approach is based on the recent concept of the Huygens’ metasurface. In such a metasurface, the fields in a given region are controlled by electromagnetic sources on the boundary surface of this region. Using this approach, a peripherally excited (PEX) metallic cavity is engineered to radiate a beam by appropriately perforating its top surface. This pencil beam can be scanned by simply changing the phases of the peripheral sources. The proposed concept has the potential to drastically reduce the required active elements in 2D phased arrays without compromising directivity. However, this also leads to constraints on the possible beam-pointing directions.

Distributed self optimization techniques for heterogeneous network environments using active antenna tilt systems

Abstract: Active antenna systems in 4G and upcoming 5G networks offer the ability to electronically steer an antenna beam in any desired direction. This unique feature makes them a suitable candidate for realizing self organizing network (SON) architectures in 5G for optimizing of key performance indicators like throughput, file transfer time etc. In this paper, we aim to analyse the effect of increasing number of input variables and complexity of learning techniques on the performance of the network. We compare performance of simple stochastic cellular learning automata (SCLA) technique with only one input to comparatively complex Q-learning technique with two or more inputs. We use FTP flow based 5G network simulator for our work. The SON architecture model proposed, is distributed with optional inter cell communication. Simulation results reveal that increasing complexity of learning process does not necessarily benefit the system performance. The simple SCLA technique shows more robust performance compared to Q-learning case. However, within the same technique increasing the number of input variables does benefit the system, indicating that a complex technique can ultimately prove beneficial in complicated scenarios provided it is able to quickly process and adapt to the environment.

Performance Evaluation of Downlink Multi-User Massive MIMO with Configurable Active Antenna System and Inter Access Point Coordination in Low-SHF-Band

Abstract: Massive multiple input and multiple output (Massive MIMO) is a key technique to achieve high system capacity and user data rate for the fifth generation (5G) radio access network (RAN). To implement Massive MIMO in 5G, how much Massive MIMO meets our expectation with various user equipment (UEs) in different environments should be carefully addressed. We focused on using Massive MIMO in the low super-high-frequency (SHF) band, which is expected to be used for 5G commercial bands relatively soon. We previously developed a prototype low-SHF-band centralized-RAN Massive MIMO system that has a flexible active antenna system (AAS)-unit configuration and facilitates advanced radio coordination features, such as coordinated beamforming (CB) coordinated multi-point (CoMP). In this study, we conduct field trials to evaluate downlink (DL) multi-user (MU)-MIMO performance by using our prototype system in outdoor and indoor environments. The results indicate that about 96% of the maximum total DL system throughput can be achieved with 1 AAS unit outdoors and 2 AAS units indoors. We also investigate channel capacity based on the real propagation channel estimation data measured by the prototype system. Compared with without-CB mode, the channel capacity of with-CB mode increases by a maximum of 80% and 104%, respectively, when the location of UEs are randomly selected in the outdoor and indoor environments. Furthermore, the results from the field trial of with-CB mode with eight UEs indicate that the total DL system throughput and user data rate can be significantly improved. key words: 5G, Massive MIMO, low-SHF-band, MU-MIMO, beamforming, C-RAN, CB, CoMP

Millimeter wave active antenna unit and inter-PCB (Printed Circuit Board) interconnection structure

Abstract: The invention relates to a millimeter wave active antenna unit and an inter-PCB (Printed Circuit Board) interconnection structure. The inter-PCB interconnection structure comprises a main board and anAIP (Antenna in package) antenna module. The main board is a first multilayer PCB and provided with a signal transmission line and a first pad electrically connected with the signal transmission line. The AIP antenna module is a second multilayer PCB and provided with a second pad, an impedance matching transmission branch, an impedance line and a signal processing circuit. The main board and theAIP antenna module adopts a mode of direct welding interconnection between the multilayer PCBs, thereby saving an expensive millimeter wave interconnection assembly on the one hand, and thus being very low in cost; On the other hand, the mode of direct welding between the boards improves the reliability of the product, the interconnection design between the multilayer PCBs can be realized, and the integration between the multilayer PCBs is greatly improved, thereby being conducive to the miniaturization design of millimeter wave equipment. In addition, the second pad and the signal processingcircuit are provided with the impedance matching transformation branch and the impedance line therebetween, thereby being suitable for a wider frequency range and a wider lamination number range.

A 60 GHz Wideband, Low-Power Active Receiving Antenna With Adjustable Polarization for SNR Improvement

Abstract: In this article, we propose a polarization adjustable active receiving antenna that covers the full 60 GHz ISM band (57–66 GHz) to improve the signal-to-noise ratio (SNR) degenerated by polarization mismatch with the transmitter. The proposed antenna not only controls the receiving angle of linear polarization (LP) but also controls the axial ratio of circular polarization (CP). For LP, the polarization angle is controlled from 0° to 180° in steps of 22.5°, while the axial ratio is controlled up to 2.6 dB by controlling the phase and amplitude of the phase shifter (P/S) and variable-gain low-noise amplifier (VGLNA) for CP case. The structure of the proposed antenna theoretically provides an SNR improvement of at least approximately 3 dB compared with the conventional active antenna in the worst case.

Novel FPGA based T/R Module Controller for Active Phased Array Radar

Abstract: The current state-of-art technologies being researched upon globally for the various functionalities like Radar, Communication, Electronics Warfare, etc., have super components that performs similar functionalities. The Active Antenna Array Unit of modern Active Phased Array Radars consists of Radiating elements, Transmit/Receive (T/R) Modules and associated RF & Digital electronics. This paper explores the existing technologies and suggests improvements for the development of futuristic Active Phased Array Radars. FPGA based T/R Module Controller (TRMC) interfaces with the higher level controller over the Low Voltage Differential Signaling. The TRMC which controls $T$ /R module is internally divided into three major sub blocks namely the Universal Asynchronous Receiver/Transmitter (UART) logic, Decoding logic and Control logic. The controller also provides real time status of critical components of the T/R Module, such as DC power supply temperature, forward power monitoring, reverse power monitoring etc. In proposed architecture we have used suitable Xilinx FPGA and achieved a switching time of <50ns. The realized unit has improved efficiency, reliability and compact without compromising the electrical parameters of T/R Module functionalities. Modern long range Active Array Radar systems are built with large number of solid state T/R Modules for realization of high power aperture product. These radars with multi-function capability require faster target update rates as well as low side lobe levels. For realization of large power aperture multiple T/R Modules are packaged in a single housing. The electronic scanning as well as low side lobe levels are achieved by controlling phase and amplitude of T/R Modules distributed in Active phased Array Radars. As a part of research, several TRMs have been realized, tested, qualified and integrated successfully with the Active Phased Array Radar.

Large-scale MIMO active antenna array applied to 5G millimeter wave communication

Abstract: The invention discloses a large-scale MIMO active antenna array applied to 5G millimeter wave communication. The large-scale MIMO active antenna array comprises an antenna array, a multifunctional board, a multi-channel TR module and a wave control power supply module, wherein the antenna array is correspondingly arranged on the multifunctional board, and the multi-channel TR module and the wave control power supply module are fixed on the multifunctional board and connected with the antenna array; the invention adopts a large-scale array antenna technology to achieve directional signal transmission, utilizes the directional gain of the phased array antenna to offset the space path loss of the signals, and utilizes the characteristic of dynamically adjustable beam pointing of the phased array antenna to achieve the multiplexing of the space dimensionality of the signals to greatly reduce the mutual interference among users, powerfully improve the capacity of the system and achieve low-power and high-efficiency signal transmission.

Over-the-Air testing of Active Antenna System Base Stations in Compact Antenna Test Range

Abstract: The definition of suitable test methods for Over the Air (OTA) measurements of non-connectorized devices is an ongoing process in several standardization committees. Among the different possibilities, the Compact Antenna Test Range (CATR) is a well-established technology that can be adapted to OTA measurement application with relatively low development efforts and therefore short deployment time. The main advantages of the use of a CATR for OTA testing is the direct measurement of Far-Field parameters, and the very wide frequency bandwith, allowing sub6GHz and mm-Wave testing.In this paper, we will summarize the performance and the testing capabilities of a short focal-length, corner-fed CATR design, providing a 1.5 m x 1.5 m cylindrical Quiet Zone, operating from 1.7 GHz to 40 GHz and upgradeable to 110 GHz, allowing OTA measurements of Active Antenna System (AAS) Base Stations (BS), installed at Ericsson premises in Sweden.

Compact Beam-Steered Resonant-Cavity Antenna Using Near-Field Phase Transformation

Abstract: The paper uses a novel near-field phase transformation beam-steering method to steer the electromagnetic energy beam of compact resonant-cavity antennas (RCAs). The method is unconventional but versatile and can be used with a variety of low-to-medium gain antennas. The use of the method for a compact RCA validates its compatibility with low-gain antennas. The far-field results predicted by numerical simulations indicate that the antenna system can scan a beam having a peak directivity of 15 dBi into a conical region having an apex angle of 70°, without dropping peak directivity more than 3dB from the maximum value. This compact beam-steering antenna system is cheaper than active antenna arrays and convenient to operate than mechanically steered reflectors. The maximum height of the system is $1.3\lambda_{0}$ , which means that the antenna can be fixed inside a cylindrical cavity and its beam direction can be remotely controlled. Due to the low-cost and elegant design of the front-end antenna, a wireless backhaul mesh network can be established, which can be dynamically adjusted to improve quality of service.

New Radio Access RF and Transceiver Design Considerations

Abstract: The NR RF characteristics are closely related to the frequency bands in which the 5G systems will be deployed. Due to wide range of the target frequency bands, spectrum flexibility was required in order to operate in diverse spectrum allocations. Such spectrum flexibility is manifested as the possibility of deployment and resource allocations in frequency bands of different sizes over an extremely wide range of contiguous or non-contiguous spectrum, both in the form of paired and unpaired frequency bands along with aggregation of different spectrum blocks within and across different bands. The NR has the capability to operate with mixed OFDM numerologies over the same or different RF carrier(s) and has relatively more flexibility compared to LTE in terms of frequency-domain scheduling and multiplexing of devices over the serving base station RF carrier(s). The use of OFDM waveform in NR provides the desired flexibility in terms of the size of the spectrum allocation and the instantaneous transmission bandwidth adaptation. The application of active antenna system concept and multiple antennas in the base stations and the devices, which emerged during LTE development, has taken a giant leap in NR with the support of massive MIMO and control/data channel beamforming both in the existing LTE bands and in the new mmWave bands. Aside from physical layer design implications, the advent of the latter features significantly impact the analog/digital RF hardware system design/implementation including filters, amplifiers, data converters, antennas, etc. In this chapter, we will discuss the new radio spectrum, RF characteristics, implementation considerations of the NR base stations and the devices as well as the hardware technologies that are used to implement various features of the new radio.

Effect of Nonlinear Distortion and Null Stability on Spatial-multiplexing Performance using 4.65-GHz-Band Active Antenna System with DPD

Abstract: This paper describes the effect of nonlinear distortion and null stability on spatial-multiplexing performance using our developed 4.65-GHz-band active antenna system with digital-pre-distortion (DPD). Superior spatial-multiplexing performance over a wide dynamic range is achieved. Due to nonlinear distortion compensation with DPD in the high-power region, the downlink (DL) signal to interference plus noise ratio (SINR) even at 16-layer is improved by 6 dB, from 19 to 25 dB, at the maximum rated output. And thanks to high precision null formation by highly accurate successive calibration in the low-power region, at 16-layer multiplexing, an SINR of 28 dB is obtained.

Analog and digital hybrid baseband multi-beam forming method and application thereof in wireless communication system

Abstract: The invention discloses an analog and digital hybrid baseband multi-beam forming method. A wireless communication system comprises a transmitting and receiving array in an active antenna unit. According to the method, a two-dimensional independent multi-beam or two-dimensional array beam is generated spatially. The invention further discloses a structure of the wireless communication system basedon the analog and digital hybrid baseband multi-beam by using the method. The structure can be used for a space-based internetwork comprising 5G wireless communication and satellite communication hopping beams. The dynamic two-dimensional independent multi-beam or two-dimensional array beam greatly increases the communication capacity. Compared with a system formed by full-digital beams, the wireless communication system has the advantages of low cost and low power consumption, and is easy to implement.