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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 IEEE Conference on Antenna Measurements & Applications (CAMA) - Va?ster?s (2018.9.3-2018.9.6)] 2018 IEEE Conference on Antenna Measurements & Applications (CAMA) - Train Communication System with Distributed Antenna System using Optical Frequency Doubler in 90 GHz Band

    摘要： A MilliMeter Wave (MMW) backhaul technology for advanced high-speed trains running a tunnel for a long distance is under development for the communication gathering a large number of passenger communications transmitting to the ground. The authors are studying a system that realizes large capacity communication between trains and the ground by arranging Distributed Antenna System (DAS) along with a long distance railway. In order to transmit a radio signal between distant antennas and the main frame of base station physically, it is necessary to avoid the influence of fiber dispersion for Radio over Fiber (RoF) which transmits a radio signal over the light. We are investigating RoF system with optical multiplication which can obtain doubled frequency after transmission. In this paper, we develop the vector modulation signal transmission by the RoF used for the downlink of the base station and report on the result of the packet communication experiment with the base station and the terminal.

    关键词： DAS,RoF,millimeter wave,Frequency multiplication

    更新于2025-11-28 14:23:57

  • Photonic generation of high-purity 60?GHz millimeter-wave signal requiring only 10?GHz radio frequency local oscillator

    摘要： A novel approach to generate 60 GHz millimeter-wave from a 10 GHz radio frequency signal using an integrated nested DD-MZM without optical filter is proposed and demonstrated. The simulation results show that the generated frequency sextupling optical mm-wave has high purity with an OSSR exceeding 29 dB and a RFSSR of 25 dB, which is consistent with the theoretical analysis. Besides, a RoF link model is established to investigate the transmission performance. The eye diagram keeps clear even when the optical mm-wave is transmitted over 60 km and the power penalty is about 0.4 dB after fiber transmission of 50 km.

    关键词： Optical fiber communication,Dual-drive Mach–Zehnder modulator (DD-MZM),Optical millimeter-wave generation

    更新于2025-09-23 15:23:52

  • Antenna Placement and Performance Tradeoffs with Hand Blockage in Millimeter Wave Systems

    摘要： The ongoing commercial deployment of millimeter wave systems brings into focus a number of practical issues in form factor user equipment (UE) design. With wavelengths becoming smaller, antenna gain patterns becoming directional, and link budgets critically dependent on beamforming, it becomes imperative to use a number of antenna modules at different locations of the UE for good performance. While more antennas/modules can enhance beamforming array gains, it comes with the tradeoff of higher component cost, power consumption of the associated radio frequency circuitry, and a beam management overhead in learning the appropriate beam weights. Thus, the goal of a good UE design is to provide robust spherical coverage corresponding to good array gains over the entire sphere around the UE with a low beam management overhead, complexity, and cost. The scope of this paper is to study the implications of two popular commercial millimeter wave UE designs (a face and an edge design) on spherical coverage. We show that analog beam codebooks can result in good performance for both the designs, and the edge design provides a better tradeoff in terms of robust performance (with hand blockage), beam management overhead, implementation complexity from an antenna placement standpoint and cost.

    关键词： hand blockage,5G-New Radio,Millimeter wave,spherical coverage,commercial deployments,antenna placement,UE design,modular design

    更新于2025-09-23 15:23:52

  • [IEEE 2018 IEEE Conference on Antenna Measurements & Applications (CAMA) - Va?ster?s (2018.9.3-2018.9.6)] 2018 IEEE Conference on Antenna Measurements & Applications (CAMA) - Pattern Reconfigurable Antenna Using A Functional Material for MMW Application

    摘要： This paper introduces a novel reconfigurable antenna for controlling radiation beam direction by using integrated phase-change material (PCM). A PCM GeTe-based parasitic patch considered as a switchable element between insulator and conductive states is applied to operate with a driven patch radiator. The direction of the radiation pattern of the antenna can be tilted by changing the state of the GeTe-based patch from its insulator to conductive state. Obtained result shows that the proposed technique is effective to control the beam direction of the antenna. Around a 400 titled angle is achieved by the insulator-to-conductor activation of the GeTe patch which can be realized by an optical source, making the antenna simple and compact without extra bias circuit. Hence, the antenna is suitable for millimeter-wave applications.

    关键词： pattern reconfigurable,millimeter wave application,GeTe-based parasitic patch

    更新于2025-09-23 15:23:52

  • Off-Grid Compressive Channel Estimation for mm-Wave Massive MIMO with Hybrid Precoding

    摘要： To reduce the pilot overhead and improve the channel estimation accuracy in the massive MIMO system, various channel estimation algorithms employing the sparse signal reconstruction (SSR) scheme have been proposed. However, the spatial grid division leads to the trade-off between the estimation accuracy and the computational complexity. In addition, when the true angle is not on the discretized grid point which is referred as off-grid problem, the performance of SSR-based algorithms will degrade heavily. In this letter, a novel channel estimation algorithm which achieves superior performance under the off-grid scenario is proposed. At first, the conventional joint angle of arrivals/departures (AoAs/AoDs) estimation is transformed into two one-dimensional sub-problems. Then, the SSR-based framework is presented to obtain the initial sparse-support set. By minimizing the constructed objective function, the off-grid errors regarded as adjustable parameters are iteratively refined. In addition, scatter gains are acquired by LSE. Numerical simulations are provided to illustrate the superiority of the proposed algorithm in terms of estimation accuracy and computational complexity.

    关键词： channel estimation,millimeter wave,massive MIMO,off-grid refinement,Compressive sensing

    更新于2025-09-23 15:23:52

  • Non-Uniform Quantization Codebook Based Hybrid Precoding to Reduce Feedback Overhead in Millimeter Wave MIMO Systems

    摘要： In this paper, we propose two non-uniform quantization (NUQ) codebook based hybrid precoding schemes for two main hybrid precoding implementations, i.e., the full-connected structure and the sub-connected structure, to reduce the feedback overhead in millimeter wave single user multiple-input multiple-output (SU-MIMO) systems. Specifically, we firstly group the angles of the arrive/departure (AOAs/AODs) of the scattering paths into several spatial lobes by exploiting the sparseness property of the millimeter wave in the angular domain, which divides the total angular domain into effective spatial lobes' coverage angles and ineffective coverage angles. Then, we map the quantization bits non-uniformly to different coverage angles and construct NUQ codebooks, where high numbers of quantization bits are employed for the effective coverage angles to quantize AoAs/AoDs and zero quantization bit is employed for ineffective coverage angles. Finally, two low-complexity hybrid analog/digital precoding schemes are proposed that utilize the NUQ codebooks. Simulation results demonstrate that, the proposed two NUQ codebook based hybrid precoding schemes achieve near-optimal spectral efficiencies and show the superiority in reducing the feedback overhead compared with the uniform quantization codebook based works.

    关键词： feedback overhead,non-uniform quantization,spatial lobe,Millimeter wave communication,hybrid precoding

    更新于2025-09-23 15:23:52

  • Beam Training and Allocation for Multiuser Millimeter Wave Massive MIMO Systems

    摘要： We investigate beam training and allocation for multiuser millimeter wave massive MIMO systems. An orthogonal pilot based beam training scheme is first developed to reduce the number of training times, where all users can simultaneously perform the beam training with the base station (BS). As the number of users increases, the same beam from the BS may point to different users, leading to beam conflict and multiuser interference. Therefore, a quality-of-service (QoS) constrained (QC) beam allocation scheme is proposed to maximize the equivalent channel gain of the QoS-satisfied users, under the premise that the number of the QoS-satisfied users without beam conflict is maximized. To reduce the overhead of beam training, two partial beam training schemes, an interlaced scanning (IS) and a selection probability (SP) based schemes, are proposed. The overhead of beam training for the IS-based scheme can be reduced by nearly half while the overhead for the SP-based scheme is flexible. Simulation results show that the QC-based beam allocation scheme can effectively mitigate the interference caused by the beam conflict and significantly improve the spectral efficiency while the IS-based and SP-based schemes significantly reduce the overhead of beam training at the cost of sacrificing spectral efficiency a little.

    关键词： beam allocation,massive MIMO,Millimeter wave (mmWave) communications,beam training

    更新于2025-09-23 15:23:52

  • [IEEE 2018 IEEE Conference on Antenna Measurements & Applications (CAMA) - Va?ster?s (2018.9.3-2018.9.6)] 2018 IEEE Conference on Antenna Measurements & Applications (CAMA) - Guidelines for Millimeter-Wave Antenna Measurements

    摘要： The characterization of physically small antennas in the millimeter-wave range has proven to be a challenge. Several research groups have developed new antenna measurement systems to be able to characterize millimeter-wave antennas. These measurement systems mainly focus on the establishment of a well-defined connection between test equipment and the antenna-under-test (AUT) for radiation pattern measurements. However, uncertainties affecting the measurement results are not always well understood. We have investigated the effect of misalignment, the effectiveness of an anechoic environment for frequencies up to 90 GHz and the impact of spurious radiation of the probe.

    关键词： anechoic environment,probe radiation,60 GHz,probe connection,uncertainty analysis,alignment,Millimeter wave,antenna measurement

    更新于2025-09-23 15:23:52

  • [IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Design of Compact SIW Bandpass Filter for Millimeter-Wave Applications

    摘要： this paper presents the design of two structures of substrate integrated waveguide (SIW) bandpass filter (BPF) for millimeter-wave application. By approaching the cruciform slot and ground vias, the numbers of resonance frequency was increased, and the filter structure can be miniaturized. Finally, the filter is designed to work at the center frequency of 22 GHz with the bandwidth of 1.4 GHz, and the numerical simulations shows good performance in the pass band and stopband.

    关键词： Compact size,Bandpass,Millimeter wave,SIW

    更新于2025-09-23 15:22:29

  • [IEEE 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Chengdu, China (2018.5.7-2018.5.11)] 2018 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - A Broadband 1-dB Noise Figure GaAs Low-Noise Amplifier for Millimeter-Wave 5G Base-Stations

    摘要： A broadband low-noise amplifier (LNA) with sub-1 dB noise figure (NF), intended for use in millimeter-wave 5G base-stations, have been fabricated in 0.1-μm InGaAs pHEMT technology. Common-source topology with inductive source degeneration is utilized for simultaneous noise and input match. Measurement results show this LNA achieves a gain of 7.9 dB at 24-GHz and a -1 dB bandwidth of 5-GHz, while consuming 13 mW from a 1-V supply. The noise figure is below 1.5 dB from 21-GHz to 27-GHz, with a lowest noise figure of 0.7 dB at 26-GHz.

    关键词： millimeter-wave,noise figure,pHEMT,5G,low-noise amplifier,GaAs

    更新于2025-09-23 15:22:29