Design of Six Element MIMO Antenna with Enhanced Gain for 28/38 GHz mm-Wave 5G Wireless Application

The fifth-generation(5G)wireless technology is the most recent standardization in communication services of interest across the globe.The concept of Multiple-Input-Multiple-Output antenna(MIMO)systems has recently been incorporated to operate at higher frequencies without limitations.This paper addresses,design of a high-gain MIMO antenna that offers a bandwidth of 400 MHz and 2.58 GHz by resonating at 28 and 38 GHz,respectively for 5G millimeter(mm)-wave applications.The proposed design is developed on a RT Duroid 5880 substrate with a single elemental dimension of 9.53×7.85×0.8 mm^(3).The patch antenna is fully grounded and is fed with a 50-ohm stepped impedance microstrip line.It also has an I-shaped slot and two electromagnetically coupled parasitic slotted components.This design is initially constructed as a single-element structure and proceeded to a six-element MIMO antenna configuration with overall dimensions of 50×35×0.8 mm^(3).The simulated prototype is fabricated and measured for analyzing its performance characteristics,along with MIMO antenna diversity performance factors making the proposed antenna suitable for 5G mm-wave and 5G-operated handheld devices.

Robustness-supported user association and small cell switching ON/OFF strategies in 5G mm-wave networks

The problem of robustness-supported user association and small cell station(SCS) switching ON/OFF strategies in 5G millimeter wave(mm-wave) networks is investigated, where the robustness of access links is ensured and the number of active SCSs is minimized for the reduction of the aggregation power consumption. Firstly, the problem is formulated as an integer programming(IP) problem. Then the problem is proved as a NP-hard problem by means of the simplification into the minimum dominant set(MDS), which is a NP-hard problem and is intractable to be solved in polynomial time. Secondly, a greedy-idea-based heuristic algorithm(GIHA) is proposed under the consideration of the complexity of the original optimization problem. Finally, superiorities of GIHA are demonstrated with the extensive simulations in 60 GHz mm-wave ultra-dense network in terms of access robustness and aggregate power consumption.

基于联邦学习的毫米波大规模MIMO的混合波束赋形和资源分配

针对大规模毫米波(millimeter wave,mm-Wave)多输入多输出(multiple input multiple output,MIMO)系统中的混合波束赋形在中心式机器学习(centralized machine learning,CML)中导致的通信开销过大问题,提出了分层联邦学习(federated learning,FL)框架下的混合波束赋形与基于合同理论的资源分配优化方法。首先,在分层系统中对多用户计算系统开销,并通过优化分配资源实现系统的效益最大化;然后,用户利用分配的资源对信道数据和相应的预编码数据进行反向传播神经网络(back propagation neural network,BPNN)模型训练,利用边缘服务器(edge server,ES)收集用户训练的权值和参数进行边缘聚合,达到一定精度后上传到云服务器(cloud server,CS)进行云聚合,直到取得最优的模型。实验结果表明,资源优化极大地降低了通信开销,并且基于FL的混合波束赋形不仅取得了和CML类似的和速率,而且其和速率要优于基于正交匹配追踪(orthogonal matching pursuit,OMP)的混合波束赋形以及全数字波束赋形方案。

High-Resolution Radiometer for Remote Sensing of Solar Flare Activity from Low Earth Orbit Satellites

Solar flares, intense bursts of radiation, can disrupt the atmosphere and potentially affect communication, navigation and electrical systems. A newly developed miniaturised microwave radiometer used on a space-borne platform should offer astronomers unprecedented understanding of the largest explosive phenomena in our solar system. In this paper the activity and results of the EU funded research project FLARES are presented. Objective of FLARES has been the study, analysis and design of millimetre-wave system-on-chip (SoC) radiometers for space-borne detection of solar flares. Thanks to the proposed methodology, the power consumption and encumbrance (volume, weight) of the instrument can be sensibly reduced when compared to the devices currently in operation for observing and studying solar flares. In particular, the proposed SoC Dicke radiometer can achieve a ten-time better resolution. This in turn, allows detecting solar flares having relatively low intensity, about 100 times lower when compared to the flares currently detected by the existing systems, owing to space-borne operations and the microchip-level miniaturization through silicon technology under space qualification.

Design of Broadband RoF PON for the Last Mile

An increase in the demand of broadband service has encouraged research and study to find a solution to offer an adequate amount of service. Living in this digital world with downloading video, voice or data leads us occasionally to have a shortage of bandwidth in the provided data. One of the solutions to cover the huge expected demand in the future is improving the communication systems by adding optical passive components to the Radio over Fiber (RoF) system. This work is mainly to increase the bandwidth that allows the small and single consumer at the last mile. We have shown that by adding the 40-GHz mm-wave to the system, Bit-Error-Rate (BER) has increased while Q-factor has decreased.

Complementary Split Ring Resonator Loaded Substrate Integrated Waveguide Leaky Wave Antenna

In this paper we present the design of a leaky wave antenna based on Substrate Integrated Waveguide (SIW) loaded by Complementary Split Ring resonator (CSRR). The proposed antenna is designed for 5G application with a center frequency around 28 GHz. The antenna is implemented on Roger RT/Duriod 5880. The loading CSRRs are designed to resonate at 28 GHz. The design is simulated by using both High-Frequency Simulation Software (HFSS) and Computer Simulation Technology (CST) for verification. Experimental measurements are also presented.

Modeling and parameter extraction of CMOS on-chip coplanar waveguides up to 67 GHz for mm-wave applications

Coplanar waveguides （CPW） are widely used in mm-wave circuits designs for their good performance. A novel unified model of various on chip CPWs for mm-wave application, together with corresponding direct parameter extraction methodologies, are proposed and investigated, where standard CPW, grounded CPW （GCPW） and CPW with slotted shield （SCPW） are included. Several kinds of influences of different structures are analyzed and considered into the model to explain the frequency-dependent per-unit-length L, C, R, and G parameters, among which the electromagnetic coupling for CPWs with large lower ground or shield is described by a new C-L-R series path in the parallel branch. The direct extraction procedures are established, which can ensure both accuracy and simplicity compared with other reported methods. Different CPWs are fabricated and measured on 90-nm CMOS processes with Short-Open-Load-Through （SOLT） de-embedding techniques. Excellent agreement between the model and the measured data for different CPWs is achieved up to 67 GHz.

Optical Generation of mm-Wave Signal Through Optoelectronic Phase-Locked Loop

In this paper, we propose a scheme for the generation of low phase noise tunable mm-wave signal by bearing two lightwaves in a photodiode. These two lightwaves are made phase coherent by an optoelectronic phase locked loop. Calculated mm-wave power at a frequency of 60 GHz is found to be -4 dBm.

50 GHz optical true time delay beamforming in hybrid optical/mm-wave access networks with multi-core optical fiber distribution

We propose and experimentally validate an optical true time delay beamforming scheme with straightforward integration into hybrid optical/millimeter（mm）-wave access networks. In the proposed approach, the most complex functions, including the beamforming network, are implemented in a central office, reducing the complexity and cost of remote antenna units. Different cores in a multi-core fiber are used to distribute the modulated signals to high-speed photodetectors acting as heterodyne mixers. The mm-wave carrier frequency is fixed to 50 GHz（VBand）, thereby imposing a progressive delay between antenna elements of a few picoseconds. That true time delay is achieved with an accuracy lower than 1 ps and low phase noise.

CMOS mm-wave transceivers for Gbps wireless communication

The challenges in the design of CMOS millimeter-wave （mm-wave） transceiver for Gbps wireless com- munication are discussed. To support the Gbps data rate, the link bandwidth of the receiver/transmitter must be wide enough, which puts a lot of pressure on the mm-wave front-end as well as on the baseband circuit. This paper discusses the effects of the limited link bandwidth on the transceiver system performance and overviews the band- width expansion techniques for mm-wave amplifiers and IF programmable gain amplifier. Furthermore, dual-mode power amplifier （PA） and self-healing technique are introduced to improve the PA＇s average efficiency and to deal with the process, voltage, and temperature variation issue, respectively. Several fully-integrated CMOS mm-wave transceivers are also presented to give a short overview on the state-of-the-art mm-wave transceivers.

Coverage and rate analysis of user beam selection in mm-wave heterogeneous networks

Millimeter wave(mm-wave)communication is widely considered to be a promising technique for 5G(Fifth Generation)cellular systems.Owing to the high path loss of mm-wave channels,5G networks could employ a heterogeneous structure that consists of an MBS(Macro Base Station)and numerous SBSs(Small Base Stations).In this paper,we analyze the coverage and rate performance of an mm-wave heterogeneous network.Using user beam selection,we derive analytical expressions for the coverage probabilities of the SBSs and MBS.Furthermore,the average achievable rate for a typical user is also investigated.It is shown that the analytical results closely follow those of the simulations with marginal differences.

High linearity U-band power amplifier design:a novel intermodulation point analysis method

A power amplifier’s linearity determines the emission signal’s quality and the efficiency of the system.Nonlinear distortion can result in system bit error,out-of-band radiation,and interference with other channels,which severely influence communication system’s quality and reliability.Starting from the third-order intermodulation point of the milimeter wave(mm-Wave)power amplifiers,the circuit’s nonlinearity is compensated for.The analysis,design,and implementation of linear class AB mm-Wave power amplifiers based on GlobalFoundries 45 nm CMOS silicon-on-insulator(SOI)technology are presented.Three single-ended and differential stacked power amplifiers have been implemented based on cascode cells and triple cascode cells operating in U-band frequencies.According to nonlinear analysis and on-wafer measurements,designs based on triple cascode cells outperform those based on cascode cells.Using single-ended measurements,the differential power amplifier achieves a measured peak power-added efficiency(PAE)of 47.2%and a saturated output power(P_(sat))of 25.2 dBm at 44 GHz.The amplifier achieves a P_(sat)higher than 23 dBm and a maximum PAE higher than 25%in the measured bandwidth from 44 GHz to 50 GHz.

Analysis and design of transformer-based CMOS ultra-wideband millimeter-wave circuits for wireless applications: a review

With a lot of millimeter-wave(mm-Wave)applications being issued,wideband circuits and systems have attracted much attention because of their strong applicability and versatility.In this paper,four transformer-based ultra-wideband mm-Wave circuits demonstrated in CMOS technologies are reviewed from theoretical analysis,implementation,to performance.First,we introduce a mm-Wave low-noise amplifier with transformer-based Gm-boosting and pole-tuning techniques.It achieves wide operating bandwidth,low noise figure,and good gain performance.Second,we review an injection-current-boosting technique which can significantly increase the locking range of mm-Wave injection-locked frequency triplers.Based on the injectionlocked principle,we also discuss an ultra-wideband mm-Wave divider with the transformer-based high-order resonator.Finally,an E-band up-conversion mixer is presented;using the two-path transconductance stage and transformer-based load,it obtains good linearity and a large operating band.

A millimeter wave linear superposition oscillator in 0.18 m CMOS technology

This paper presents a millimeter wave （mm-wave） oscillator that generates signal at 36.56 GHz. The ram-wave oscillator is realized in a UMC 0.18 μm CMOS process. The linear superposition （LS） technique breaks through the limit of cut-off frequency （JET）, and realizes a much higher oscillation than Jr. Measurement results show that the LS oscillator produces a calibrated 37.17 dBm output power when biased at 1.8 V; the output power of fundamental signal is -10.85 dBm after calibration. The measured phase noise at 1 MHz frequency offset is -112.54 dBc/Hz at the frequency of 9.14 GHz. This circuit can be properly applied to mm-wave communication systems with advantages of low cost and high integration density.

Potential of asymmetrical Si/Ge and Ge/Si based hetero-junction transit time devices over homo-junction counterparts for generation of high power

Static and dynamic properties of both complementary n-Ge/p-Si and p-Ge/n-Si hetero-junction DoubleDrift IMPATT diodes have been investigated by an advanced and realistic computer simulation technique, devel- oped by the authors, for operation in the Ka-, V- and W-band frequencies. The results are further compared with corresponding Si and Ge homo-junction devices. The study shows high values of device efficiency, such as 23%, 22% and 21.5%, for n-Ge/p-Si IMPATTs at the Ka, V and W bands, respectively. The peak device negative con- ductances for n-Si/p-Ge and n-Ge/p-Si hetero-junction devices found to be 50.7× 10^6 S/m^2 and 71.3× 106 S/m^2, which are -3-4 times better than their Si and Ge counterparts at the V-band. The computed values of RF powerdensity for n-Ge/p-Si hetero-junction IMPATTs are 1.0 ×10^9, 1.1 × 10^9 and 1.4× 10^9 W/m^2, respectively, for Ka-, V- and W-band operation, which can be observed to be the highest when compared with Si, Ge and n-Si/p-Ge devices. Both of the hetero-junctions, especially the n-Ge/p-Si hetero-junction diode, can thus become a superior RF-power generator over a wide range of frequencies. The present study will help the device engineers to choose a suitable material pair for the development of high-power MM-wave IMPATT for applications in the civil and defense-related arena.

A Concentric Array for Generating Multimode OAM Waves

For the problem of multiplexing multimodal vortex electromagnetic waves,a double-ring concentric uniform circular array(CUCA)consisting of 12 circularly polarized antennas(4 inner rings and 8 outer rings)is proposed in this paper.A complex feeding network is solved by rotating the circularly polarized antennas at a certain angle.The antennas are rotationally symmetric and point to the center,generating orbital angular momentum(OAM)waves by feeding the same amplitude and phase signals.In addition,this paper combines millimeter wave(mm-wave)and ultra-wideband(UWB)with OAM.The proposed antenna array can generate OAM beams at 30∼40 GHz with l=−1,−2.When l=−1 the relative bandwidth is 25.2% and the gain is 8.03 dBi;when l=−2 the relative bandwidth is 27.7% and the gain is 9.43 dBi.The analysis of simulation results shows that the antenna array has UWB performance,good gain,and a standard spiral phase distribution,which can provide some practical significance for modal multiplexing of mm-wave band OAM.

Antenna Design for Modern Mobile Phones: A Review

Due to limited antenna space,high communication requirements,and strict regulatory constraints,the design of antennas for modern mobile phones has become an exceedingly challenging task.In recent years,numerous studies have been conducted in this area,leading to significant advancements.This review paper comprehensively summarizes recent progress made in antenna design for modern mobile phones.Firstly,the challenges faced in antenna design for modern mobile phones are described,including bandwidth enhancement,integration and decoupling techniques,mm-wave array antennas,satellite communication antennas,as well as interactions between mobile antennas and the human body.Secondly,the basic antenna types(such as inverted-F,slot,loop,and planar inverted-F antennas)commonly used in modern metal-bezel mobile phones along with their key characteristics are briefly summarized.Thirdly,the commonly exployed methods used in practical applications for designing wideband antennas within compact sizes and achieving decoupling among multiple antennas with wide bandwidths are collected.Fourthly,recent advances in the design of compact,wideband,and wide-angle scanning mm-wave arrays for modern mobile phones are summarized.Fifthly,recent progress made in satellite communication antenna designs for modern mobile phones,including broadside and end-fire radiation patterns,is presented.Sixthly,recent studies on the interaction between mobile antennas and the human body are briefly concluded.Finally,the future challenge of antenna design for mobile phones is briefly discussed.It is our hope that this comprehensive review will provide readers with a systematic understanding of antenna design principles applicable to modern mobile phones.