热点论文与带您领略5G/6G材料技术的最新发展——图书馆前沿文献专题推荐服务（20）

2020-09-18

 

       在上一期前沿文献中推荐中，从的6G的网络形态，6G网络的智能化演进，编码技术的发展，以及毫秒级通信交互和极高可靠性的 in-X子网等方向进行了讨论。
       在本期中，针对5G和6G通信系统的研究热点和系统演进，将主要的关注点落在了与通信性能密切相关的射频开关、天线阵列、功放介质以及波束成形器件等方面，并选取了最新的文献，推送给相关领域的科研人员，共同研讨。
 
Boron nitride switches for 5G and beyond
Frank Schwierz
Nature Electronics, 2020, 3: 444–445
Monolayers of boron nitride can be used to build high-performance radio-frequency switches that can operate at the frequencies required for 5G and the communication systems beyond it.
 
Power Amplifiers for mm-Wave 5G Applications: Technology Comparisons and CMOS-SOI Demonstration Circuits
Peter M. Asbeck, etc.
IEEE Transactions on Microwave Theory and Techniques,2019,67(7): 3099 - 3109
A review is presented of key power amplifier (PA) performance requirements for millimeter-wave 5G systems, along with a comparison of the potential of different semiconductor technologies for meeting those requirements. Output power, efficiency, and linearity considerations are highlighted, and related to semiconductor material characteristics. Prototype 5G PAs based on silicon technologies are then reviewed, with primary emphasis on CMOS-SOI. Stacked FET PAs based on nMOS and pMOS for 28-GHz operation are presented, along with outphasing and Doherty amplifiers. Peak power-added efficiency (PAE) up to 46% is demonstrated for a two-stack pMOS amplifier with saturation power (Psat) above 19 dBm. PAE at 6 dB backoff above 27% is shown for an nMOS Doherty PA with 22-dBm Psat. Operation with 64QAM OFDM modulation signals at 800-MHz bandwidth is reported, with up to 13-dBm output power and more than 17% PAE, without the use of digital predistortion. Future challenges for PA development are discussed.
 
An All-Metal High-Gain Radial-Line Slot-Array Antenna for Low-Cost Satellite Communication Systems
Mst Nishat Yasmin Koli, etc
IEEE Access, 2020, 8: 139422 - 139432
This article presents a method to produce a highly directive circularly polarized radiation beam (gain>35 dBi) from an all-metal circularly polarized radial-line slot array (RLSA) antenna. The antenna comprises a single-layer radial TEM waveguide, fully filled with air, formed between a metal ground plate and a parallel metal slotted sheet, leading to simple, low-cost fabrication. A prototype of the new antenna having a diameter of 0.4 m or 27λ₀ , where λ₀ is the free-space wavelength at the operating frequency of 20 GHz, was fabricated and tested. Its measured peak broadside directivity and measured peak realized gain are 36.3 dBic and 35.9 dBic, respectively. The total thickness of the antenna is only 6.5 mm or 0.43λ₀ . The aperture efficiency of the prototype is 56%, total efficiency is 95.4%, and measured 3-dB axial ratio bandwidth is 4.9 GHz (22.9%). The antenna has excellent cross-polar rejection, with a measured cross-polar level of −24.4 dB in the broadside direction. This antenna has been targeted for low-cost SATCOM terminals and wireless backhauls but due to the lack of dielectrics, it may also be useful for space and high-power microwave applications.
 
Laser-Drilled All-Dielectric Huygens’ Transmit-Arrays as 120 GHz Band Beamformers
Mohamed K. Emara , etc.
IEEE Access,2020,8: 153815 - 153825
An all-dielectric Huygens’ transmit-array is proposed and experimentally demonstrated in the 120-GHz-band. The proposed transmit-array is fabricated using a high-precision laser-drilling process providing high fabrication precision and accuracy. A non-uniform Huygens’ surface is next placed on top of a planar high gain slot-array antenna for far-field beamforming. Full-wave simulations are first used to demonstrate the beamforming capability by generating difference-pattern beams as an example. A uniform transmit-array was then fabricated and characterized to investigate the effect of the transmit-array on the antenna performance, along with showing very low fabrication tolerances and minimal dimensional variation due to the laser drilling process. Next, a phase-gradient transmit-array for beam-tilting is experimentally demonstrated as a practical example of beamforming. The proposed all-dielectric structure is the first Huygens’ structure to be demonstrated at these frequency bands, and represents an attractive alternative to conventional metallic Huygens’ metasurfaces based on standard printed circuit board (PCB) solutions.