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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • Schottky diodes
  • frequency multipliers
  • submillimeter-wave technology
  • terahertz technology.
  • Submillimeter-wave sources
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • California Institute of Technology
201 条数据
?? 中文（中国） ▾

  • [IEEE 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz 2018) - Nagoya (2018.9.9-2018.9.14)] 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Phase Processing in Millimeter Wave Inverse Synthetic Aperture Radar Imaging of Ship Targets

    摘要： The shore-based inverse synthetic aperture radar (ISAR) imaging of ship targets has important significance for national defense. However, imaging of ship targets is a tough problem because of their complex movement on the sea. The complex movement makes the phase of the radar echoes more complex, causing great difficulties in phase processing and focusing in azimuth. In this paper, experiments on imaging of a boat with a wideband millimeter wave radar system were carried out, and a high order phase gradient autofocus (PGA) algorithm was adopted during phase processing. The comparison with several traditional phase processing algorithms proves the good performance of our method in maneuvering targets imaging.

    关键词： ship targets,millimeter wave radar,PGA algorithm,phase processing,ISAR imaging

    更新于2025-09-04 15:30:14

  • Performance Analysis of Interference and Eavesdropping Immunity in Narrow Beam mmWave Networks

    摘要： Exploiting highly directional antenna arrays to compensate for severe propagation loss is one of the defining features in millimeter-wave (mmWave) communications. With efficient beamforming techniques, mmWave transceivers can form steerable narrow beams. Therefore, different from convenient microwave networks, the signal or interference power in mmWave communications is highly directional and closely related to critical parameters such as interference distance and angles of departure/arrival. The high directivity implies that the co-channel interference among simultaneously active mmWave links can be expected to be significantly smaller than that for omnidirectional links and, meanwhile, the security of mmWave communications may also be enhanced. In this context, will the traditional interference mitigation and physical-layer security techniques still be efficient or necessary in mmWave networks? The answer may be negative in certain conditions. However, there is no detailed analysis on the conditions for this issue. In this paper, we jointly analyze the inter-beam interference and secrecy performance of mmWave communications for their close relation to signal-to-interference-plus-noise ratio. We also derive various performance limits (e.g., interference/eavesdropping distance limit, transmission power limit, offset angle limit, and beamwidth limit) of interference and eavesdropping immunity in mmWave networks. The theoretical and numerical results verify our analysis.

    关键词： immunity,inter-beam interference,narrow beams,physical layer security,eavesdropping,Millimeter wave (mmWave)

    更新于2025-09-04 15:30:14

  • Atmospheric turbulence mitigation using spatial mode multiplexing and modified pulse position modulation in hybrid RF/FSO orbital-angular-momentum multiplexed based on MIMO wireless communications system

    摘要： In this paper, the capacity of a free-space optical (FSO) communication over radio frequency (RF) could potentially be increased by the simultaneous transmission of multiple orbital angular momentum (OAM) based on spatial mode multiplexing (SMM) as an additional effective degree of freedom (EDOF) and quadrature amplitude modulation (QAM). This paper describes using hybrid RF/FSO-OAM based on multiple-input multiple-output (MIMO)/SMM using M-ary modified pulse position modulation (MPPM) and spatial PPM (SPPM) for potentially enhancing capacity in wireless communication systems. We present an analytical system design concerning OAM multiplexing and MIMO/SMM processing in free space communications channel under atmospheric turbulence (AT). Here, we assume a new architecture that closes the gap in speeds between millimeter-wave (mm-wave) wireless and optical links. In this study, we highlight recent advances in the use of OAM multiplexing for high-capacity FSO and mm-wave communications. We have developed the MPPM in FSO communication over RF using the source Gaussian model and SMM by proposing a new version of hybrid SPPM and MPPM. The novelty approach presents performance enhancement of the acquisition, pointing, tracking position and AT mitigation of link. We propose to use SMM combined with OAM-QAM based MIMO communications system to mitigate both weak and strong turbulence distortions. Simulation results show that the capacity of OAM-based MIMO system outperforms the capacity of the conventional MIMO system when the propagation distance is larger than a specific threshold. The use of transmitter lenses could enhance the OAM beams with a larger mode spacing (MS) of 2 (OAM l +1, l +3, l +5, l +7 transmitted) shows a lower power penalty (PP) when the inter-channel crosstalk overwhelms a larger lateral displacement of about 2 mm. Using the lenses at the transmitter to focus OAM beams could reduce power loss and PP in OAM-based FSO links and that this improvement might be more significant for higher-order OAM beams and provide high power-efficiency. With a larger of the transmitter and receiver 8 cm, 10 cm aperture size respectively, the system with mode spacing of 2 (OAM l +1, l +3, l +5, l +7 transmitted) and mode spacing of 3 (OAM l +1, l +4, l +7, l +10 transmitted) of OAM beams based on MIMO should fulfill lower-power penalty of 2.2 dB, 3.4 dB, as respectively and could enhance system robustness under angular error but degrade tolerance of lateral displacement. The proposed system provides an excellent signal-to-noise ratio (SNR) for the capacity in the regime of strong atmospheric turbulence. In this way, the maximization of FSO communication and RF wide, the data capacity enhancement, and it is considered a massive solution in the bandwidth provision for future access networks. This work could be beneficial to the practical implementation of OAM-MIMO/SMM multiplexed RF/FSO links.

    关键词： Multiple-input multiple-output,Spatial mode multiplexing,Orbital angular momentum,Free space optical communications,Millimeter-wave communications,Modified pulse position modulation

    更新于2025-09-04 15:30:14

  • [IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - Differential Absorption Radar at 170 GHz for Atmospheric Boundary Layer Water Vapor Profiling

    摘要： We develop a frequency-modulated continuous-wave (FMCW) radar between 167 and 174.8 GHz to measure differential absorption due to water vapor within the atmospheric boundary layer. In this work, we report on single-frequency measurements performed within this band in the presence of precipitating clouds. Despite the relatively low transmit power of 6-10 dBm, the high transmit/receive isolation and low noise figure of the system enables detection of radar echos from rain or clouds with high signal-to-noise ratio (SNR) out to about one kilometer. This work builds on technology developed and measurements performed in our group in the 183.5 to 193 GHz band, which is subject to transmission restrictions due to passive remote sensing platforms that rely on those frequencies.

    关键词： Meteorological radar,Millimeter wave radar,Radar signal processing

    更新于2025-09-04 15:30:14

  • [IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - Measurement of Shock Wave and Particle Velocities in Shocked Dielectric Material from Millimeter-Wave Remote Sensing

    摘要： A millimeter-wave remote sensing technique is used here as a noninvasive and continuous approach for the real-time measurement of shock wave velocity as well as the velocity of the shocked dielectric material during an impact. Experimental results obtained from planar symmetric impacts on PolyMethyl MethAcrylate (PMMA) cylinders are discussed and demonstrate that the proposed millimeter-wave remote sensing technique is highly convenient for deriving both the velocity of the shock wave and velocity of the shocked PMMA material. The proposed approach is applicable to any dielectric material subject to an impact and is an excellent candidate for deriving the equation of state of shocked materials.

    关键词： Millimeter wave remote sensing,equation of state.,velocity measurement,Doppler radar,shock waves

    更新于2025-09-04 15:30:14

  • [Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Dual-port dual-band (28/38 GHz) SIW leaky wave antenna for 5G base stations

    摘要： This paper presents a novel dual-port dual-band (28/38GHz) substrate integrated waveguide (SIW) antenna with stepped long slots (SLS) for base stations in fifth generation (5G) communication systems. A stepped long slot on the top side of an SIW waveguide with a changing width creates a wide and rotated beam, which is desired in some specific 5G applications. One of the unique advantages of the design is its embedded duplexer separating the 28 GHz and 38 GHz ports at opposite sides of the antenna. A wide impedance bandwidth in both bands is obtained. The realized gain of the antenna is around 11.56 dBi and 12.08 dBi in both bands, respectively. The 6 dB beamwidths are 23o and 16o at 28 GHz and 38 GHz. The structure has good frequency scanning properties and is suitable for sectored base station topologies.

    关键词： 5G,dual band antennas,millimeter wave antennas,SIW

    更新于2025-09-04 15:30:14

  • [Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Compact Broadband Electronically Controllable SIW Phase Shifter for 5G Phased Array Antennas

    摘要： This work presents a novel compact and broadband electronically controllable substrate integrated waveguide (SIW) phase shifter intended for beamsteering applications in antenna arrays for 5G wireless communication. The proposed phase shifter is designed to operate over a large bandwidth (26 GHz – 32 GHz) with a simulated maximum insertion loss of less than 3 dB and a maximum phase difference of more than 1000+50 over the entire band. The phase shift is provided via metal posts which are switched between capacitive and inductive loading through beam-lead PIN diodes.

    关键词： 5G,antennas,Phase shifter,antenna arrays,SIW,millimeter wave

    更新于2025-09-04 15:30:14

  • Nanotechnology-Empowered Flexible Printed Wireless Electronics

    摘要： In this article, the particular importance of nanotechnology-enabled materials associated with additive manufacturing techniques for the realization of radio-frequency (RF) components and modules for Internet of Things (IoT) and millimeter-wave (mm-wave) applications is discussed. First, a look into the preparation of functional nanomaterial inks for chemical sensing applications and the surface modification processes required for their excellent printability is provided. The focus then shifts toward numerous applications realized through the implementation of the previously listed techniques. These applications discuss origami [morphing/four-dimensional (4-D)-printed] structures, taking advantage of the unique benefits of bending and folding on the printed conductive nanomaterials-based traces on a paper substrate for the fabrication of foldable reconfigurable RF architectures. Then, the synergistic integration of inkjet-printed carbon-based nanomaterials sensors with ultrahigh performance flexible printed antenna structures—utilizing nanoparticles—for the Internet of skins, smart cities, and fifth-generation (5G) applications is described. We then demonstrate the critical importance of nanomaterial-based inks in the development of robust three-dimensional (3-D)-printed RF interconnects with groundbreaking performance, opening the door for the next generation of electronics manufacturing and packaging on virtually every substrate up to frequencies in the sub-THz range.

    关键词： origami structures,5G applications,additive manufacturing,millimeter-wave,nanotechnology,Internet of Things,radio-frequency,nanomaterial inks,chemical sensing,flexible electronics

    更新于2025-09-04 15:30:14

  • [IEEE 2018 11th Global Symposium on Millimeter Waves (GSMM) - Boulder, CO, USA (2018.5.22-2018.5.24)] 2018 11th Global Symposium on Millimeter Waves (GSMM) - 57 GHz 130 uW CMOS Millimeter-Wave Oscillator for Ultra Low Power Sensor Node

    摘要： Millimeter-wave sensor network will be conduce to very small and secure wireless tags. Conventional oscillator of millimeter-wave is mainly developed to reduce the phase noise and increase the tuning range and power consumption is larger than 1mW. The ultra-low power consumption oscillator, which has power consumption of less than 1mW, is needed to achieve millimeter-wave sensor network. In this paper, the design methodology is proposed for ultra-low power consumption oscillator. The fabricated IC performs 57.4GHz with 130μW power consumption. The FOM is 10dB higher than those of previously reported.

    关键词： Sensor network,Sensor node,Low power consumption,Millimeter-wave oscillator

    更新于2025-09-04 15:30:14

  • [IEEE 2018 13th European Microwave Integrated Circuits Conference (EuMIC) - Madrid, Spain (2018.9.23-2018.9.25)] 2018 13th European Microwave Integrated Circuits Conference (EuMIC) - Ultra-Broadband Frequency Multiplier MMICs for Communication and Radar Applications

    摘要： Two H-band frequency multiplier MMICs, a frequency doubler and tripler, are presented. Both circuits were characterized over a frequency range of 235 - 285 GHz. The 3-dB bandwidth of both chips exceeds the measurement range of 50 GHz. Without any post-ampli?cation the multiplier-by-3 achieves an average output power of -6 dBm at an input power of 6 dBm. The multiplier-by-two generates -3.6 dBm average at an input power of 5 dBm. Both MMICs were realized in a 35 nm gate-length InGaAs-based metamorphic HEMT technology. A comparison of simulation and measurement was conducted and shows a very good correspondence.

    关键词： S-MMIC,Frequency conversion,Millimeter wave communication

    更新于2025-09-04 15:30:14