A 24−30 GHz 8-element dual-polarized 5G FR2 phased-array transceiver IC with 20.8-dBm TX OP1dB and 4.1-dB RX NF in 65-nm CMOS

This article presents an 8-element dual-polarized phased-array transceiver(TRX)front-end IC for millimeter-wave(mm-Wave)5G new radio(NR).Power enhancement technologies for power amplifiers(PA)in mm-Wave 5G phased-array TRX are discussed.A four-stage wideband high-power class-AB PA with distributed-active-transformer(DAT)power combining and multi-stage second-harmonic traps is proposed,ensuring the mitigated amplitude-to-phase(AM-PM)distortions across wide carrier frequencies without degrading transmitting(TX)power,gain and efficiency.TX and receiving(RX)switching is achieved by a matching network co-designed on-chip T/R switch.In each TRX element,6-bit 360°phase shifting and 6-bit 31.5-dB gain tuning are respectively achieved by the digital-controlled vector-modulated phase shifter(VMPS)and differential attenuator(ATT).Fabricated in 65-nm bulk complementary metal oxide semiconductor(CMOS),the proposed TRX demonstrates the measured peak TX/RX gains of 25.5/21.3 dB,covering the 24−29.5 GHz band.The measured peak TX OP1dB and power-added efficiency(PAE)are 20.8 dBm and 21.1%,respectively.The measured minimum RX NF is 4.1 dB.The TRX achieves an output power of 11.0−12.4 dBm and error vector magnitude(EVM)of 5%with 400-MHz 5G NR FR2 OFDM 64-QAM signals across 24−29.5 GHz,covering 3GPP 5G NR FR2 operating bands of n257,n258,and n261.

Application of X-band Polarimetric Phased-array Radars in Quantitative Precipitation Estimation

The performance of different quantitative precipitation estimation(QPE) relationships is examined using the polarimetric variables from the X-band polarimetric phased-array radars in Guangzhou,China.Three QPE approaches,namely,R(ZH),R(ZH,ZDR) and R(KDP),are developed for horizontal reflectivity,differential reflectivity and specific phase shift rate,respectively.The estimation parameters are determined by fitting the relationships to the observed radar variables using the T-matrix method.The QPE relationships were examined using the data of four heavy precipitation events in southern China.The examination shows that the R(ZH) approach performs better for the precipitation rate less than 5 mm h-1, and R(KDP) is better for the rate higher than 5 mm h-1, while R(ZH,ZDR) has the worst performance.An adaptive approach is developed by taking the advantages of both R(ZH) and R(KDP) approaches to improve the QPE accuracy.

Rapid-Scan and Polarimetric Phased-Array Radar Observations of a Tornado in the Pearl River Estuary

The strong destructive winds during tornadoes can greatly threaten human life and destroy property.The increasing availability of visual and remote observations,especially by Doppler weather radars,is of great value in understanding tornado formation and issuing warnings to the public.In this study,we present the first documented tornado over water detected by a state-of-the-art dual-polarization phased-array radar(dual-PAR)in China.In contrast to new-generation weather radars,the dual-PAR shows great advantages in tornado detection for its high spatial resolution,reliable polarimetric variables,and rapid-scan strategy.The polarimetric signature of copolar cross-correlation coefficient with anomalously low magnitude appears to be effective for verifying a tornado and thus is helpful for issuing tornado warnings.The Guangdong Meteorological Service has been developing an experimental X-band dual-PAR network in the Pearl River Delta with the goal of deploying at least 40 advanced dual-PARs and other dual-polarization weather radars before 2035.This network is the first quasi-operational X-band dual-PAR network with unprecedented high coverage in the globe.With such high-performance close-range PARs,efficient operational nowcasting and warning services for small-scale,rapidly evolving,and damaging weather(e.g.,tornadoes,localized heavy rainfall,microbursts,and hail)can be expected.

A novel static shape-adjustment technique for planar phased-array satellite antennas

Planar phased-array satellite antennas deform when subjected to external disturbances such as thermal gradients or slewing maneuvers.Such distortion can degrade the coherence of the antenna and must therefore be eliminated to maintain performance.To support planar phased-array satellite antennas,a truss with diagonal cables is often applied,generally pretensioned to improve the stiffness of the antenna and maintain the integrity of the structure.A new technique is proposed herein,using the diagonal cables as the actuators for static shape adjustment of the planar phased-array satellite antenna.In this technique,the diagonal cables are not pretensioned;instead,they are slack when the deformation of the antenna is small.When using this technique,there is no need to add redundant control devices,improving the reliability and reducing the mass of the antenna.The finite element method is used to establish a structural model for the satellite antenna,then a method is introduced to select proper diagonal cables and determine the corresponding forces.Numerical simulations of a simplified two-bay satellite antenna are first carried out to validate the proposed technique.Then,a simplified 18-bay antenna is also studied,because spaceborne satellite antennas have inevitably tended to be large in recent years.The numerical simulation results show that the proposed technique can be effectively used to adjust the static shape of planar phased-array satellite antennas,achieving high precision.

Mathematical Simulating Model of Phased-Array Antenna in Multifunction Array Radar

A mathematical simulating model of phased-array antenna in multifunction array radar has been approached in this paper, including the mathematical simulating model of plane phased array pattern, the mathematical simulating model of directionality factor, the mathematical simulating model of array factor, the mathematical simulating model of array element factor and the mathematical simulating model of beam steering.

A New X-band Weather Radar System with Distributed Phased-Array Front-ends: Development and Preliminary Observation Results

A novel weather radar system with distributed phased-array front-ends was developed. The specifications and preliminary data synthesis of this system are presented, which comprises one back-end and three or more front-ends. Each front-end, which utilizes a phased-array digital beamforming technology, sequentially transmits four 22.5°-width beams to cover the 0°–90° elevational scan within about 0.05 s. The azimuthal detection is completed by one mechanical scan of0°–360° azimuths within about 12 s volume-scan update time. In the case of three front-ends, they are deployed according to an acute triangle to form a fine detection area(FDA). Because of the triangular deployment of multiple phased-array front-ends and a unique synchronized azimuthal scanning(SAS) rule, this new radar system is named Array Weather Radar(AWR). The back-end controls the front-ends to scan strictly in accordance with the SAS rule that assures the data time differences(DTD) among the three front-ends are less than 2 s for the same detection point in the FDA. The SAS can maintain DTD < 2 s for an expanded seven-front-end AWR. With the smallest DTD, gridded wind fields are derived from AWR data, by sampling of the interpolated grid, onto a rectangular grid of 100 m ×100 m ×100 m at a 12 s temporal resolution in the FDA. The first X-band single-polarized three-front-end AWR was deployed in field experiments in 2018 at Huanghua International Airport, China. Having completed the data synthesis and processing, the preliminary observation results of the first AWR are described herein.

Second-harmonic generation in focused beam fields of phased-array transducers in a nonlinear solid with a stress-free boundary

In nonlinear acoustic harmonic generation in solids with stress-free boundaries,such a boundary is known to destructively change the second harmonic generation,and the pulse-echo method is not practically applicable.Focused beams have often been used for fluid nonlinearity and biomechanical imaging in pulse-echo test setups.This paper considers the focused beam fields of linear phased-array transducers to ensure that pulse-echo harmonic generation can be applied to solids with stress-free boundaries.The fundamental and second-harmonic beam fields that are focused and reflected at the stress-free and rigid boundaries are calculated and their properties are investigated in terms of the received average fields.The phase difference between the two second-harmonic components after reflection from the boundary—that is,the reflected and the newly generated second harmonic—is emphasized.The phase difference is used to explain the improved and accumulated second harmonic observed in the simulation results.

Adaptive Tracking for Beam Alignment Between Ship-Borne Digital Phased-Array Antenna and LEO Satellite

In mobile satellite communication networks employing digital beam forming technology,beam alignment imposes great influence on link quality and network efficiency.Owing to complex coupling motion by low earth orbit(LEO)satellite and ship,direction of arrival(DOA)of target satellite varies rapidly and nonlinearly.It then causes difficulty to accurately track the DOA.In this work,an adaptive tracking algorithm is proposed by exploiting advantages of flexible parameter configuration of digital phased-array antenna.The alignment process basically consists of observation and tracking.In the observation stage,two-dimensional(2-D)multiple signal classification(MUSIC)is applied by the ship-borne digital phased-array antenna to estimate beam direction of satellite;in the tracking stage,an extended Kalman filter(EKF)based adaptive tracking is designed to achieve fast and accurate alignment.The proposed adaptive tracking improves performance by adaptively estimating tracking parameters in EKF firstly.The estimation results are then used as feedback to adaptively adjust digital phased-array antenna parameters to improve estimation accuracy of DOA.Simulation results under sea state 5 show that the proposed tracking algorithm improves tracking accuracy and stability over conventional ones.

Design of Millimeter-Wave Antenna-in-Package(AiP)for 5G NR

For 5G new radio(NR),there are two frequency bands:Frequency Range 1(FR‐1)(low frequency)and Frequency Range 2(FR‐2)(millimeter‐wave frequency).Millimeter‐wave has been officially utilized in mobile applications.The wide bandwidth is the key for the millimeter-wave band.However,higher loss has become the major challenge for the wide use of this frequency range.Antenna array and beamforming technologies have been introduced to resolve the path loss and coverage problems.The key design considerations of the beamforming antenna array are low loss,compact system and small size.Antenna-in-package(AiP)has become the most attractive technology for millimeter-wave front-end system.For the design of AiP,many parameters such as RF transition,material and heat need to be considered and designed properly.The Over‐the‐Air(OTA)testing technology is also very critical for AiP mass production.In this paper,the detail of AiP design and new OTA testing technology are discussed and demonstrated.

Automatic Discontinuity Classification of Wind-turbine Blades Using A-scan-based Convolutional Neural Network

Recent development trends in wind power generation have increased the importance of the safe operation of wind-turbine blades(WTBs). To realize this objective, it is essential to inspect WTBs for any defects before they are placed into operation. However, conventional methods of fault inspection in WTBs can be rather difficult to implement, since complex curvatures that characterize the WTB structures must ensure accurate and reliable inspection. Moreover, it is considered useful if inspection results can be objectively and consistently classified and analyzed by an automated system and not by the subjective judgment of an inspector. To address this concern,the construction of a pressure-and shape-adaptive phased-array ultrasonic testing platform, which is controlled by a nanoengine operation system to inspect WTBs for internal defects, has been presented in this paper. An automatic classifier has been designed to detect discontinuities in WTBs by using an A-scanimaging-based convolutional neural network(CNN). The proposed CNN classifier design demonstrates a classification accuracy of nearly 99%. Results of the study demonstrate that the proposed CNN classifier is capable of automatically classifying the discontinuities of WTB with high accuracy, all of which could be considered as defect candidates.

Interval type-2 fuzzy logic based radar task priority assignment method for detecting hypersonic-glide vehicles

A radar task priority assignment method based on interval type-2 fuzzy logic system(IT2 FLS)was designed to solve the problem of resource management for phased-array radar to detect hypersonic-glide vehicles(HGVs).The mathematical model of the radar task and the motion and detection models of HGVs are described in detail.The target threat of an HGV is divided into maneuver,speed,azimuth,and distance threats.In the radar task priority assignment method based on IT2 FLS,the maneuver factor,speed,azimuth difference,distance,and initial priority are input variables.The radar task priority is the output variable.To reduce the number of fuzzy rules and avoid rule explosion,an IT2 FLS with a hierarchical structure was designed.Finally,the feasibility of the task priority assignment method was verified by simulations.Simulation results showed that the method based on IT2 FLS has a higher precise tracking rate,mean initial priority,and target threat degree,and a shorter offset time.