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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） ▾

  • Complex Permittivity Measurement of Paraffin Phase-Change Material at 26 GHz–1.1 THz Using Time-Domain Spectroscopy

    摘要： We report complex permittivity measurement of hexatriacontane films at the frequency range of 26 GHz–1.1 THz. Hexatriacontane (C36H74) has a melting point of 75 ?C that exhibits a 15% volumetric change which is crucial in developing low-loss RF microactuators with large displacement. In this work, we employ time-domain spectroscopy to measure the transmission coefficient of the paraffin samples in the frequency range of 0.3–1.1 THz. In order to extract the dielectric constant and accurately estimate the small values of loss tangent, we developed a propagation model which measured data are fitted to through a new least-squares minimization method. A Debye relaxation model is used to model the frequency dependence of the permittivity. Described method is rapidly convergent with minimum amount of signal processing. This method can be used to determine the complex permittivity of the materials by devising an appropriate function for the frequency dependence of the complex permittivity. Transmission through 20 samples of paraffin with various thicknesses is measured and the average permittivity is found to be 2.25 with standard deviation of 0.028. The loss tangent is monotonically increasing with frequency and the maximum value is 6.32×10?3 at 1.1 THz. Our study demonstrates that paraffin is a low-loss dielectric which makes it an attractive candidate for development of electro-thermo-mechanical actuators for sub-millimeter- and millimeter wave (mmW) variable capacitors, low-loss reconfigurable antennas, and phase shifters.

    关键词： Terahertz,Time-domain spectroscopy,Loss tangent,Millimeter wave,Alkane,Paraffin,Complex permittivity

    更新于2025-09-23 15:21:21

  • [IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Features of Millimeter-Wave Ultra-Wideband Signals Application in Telecommunications

    摘要： In the paper, the features of millimeter-wave ultra-wideband signals application, related to photon methods of generation and transmission of millimeter-wave signals, as well as the quasi-optical approach for modeling signal loss (amplification) are considered. It is proposed to use more accurate models of millimeter-wave ultra-wideband radio systems, which should correspond to the fundamental physical features of the propagation of millimeter waves, especially in urban conditions. It is shown that when calculating such systems it is necessary to take into account the noise associated with the method of generating millimeter waves.

    关键词： energy budget,wireless communications,noise regime,ultra-wideband signal,millimeter-wave,radio-over-fiber

    更新于2025-09-23 15:21:21

  • [IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Studies on Co-sputtered Al-Zn-Sn-O Films: A New TCO for Thin film Solar Cells

    摘要： Hybrid analog/digital multiple-input multiple-output architectures were recently proposed as an alternative for fully digital-precoding in millimeter wave wireless communication systems. This is motivated by the possible reduction in the number of RF chains and analog-to-digital converters. In these architectures, the analog processing network is usually based on variable phase shifters. In this paper, we propose hybrid architectures based on switching networks to reduce the complexity and the power consumption of the structures based on phase shifters. We define a power consumption model and use it to evaluate the energy efficiency of both structures. To estimate the complete MIMO channel, we propose an open-loop compressive channel estimation technique that is independent of the hardware used in the analog processing stage. We analyze the performance of the new estimation algorithm for hybrid architectures based on phase shifters and switches. Using the estimate, we develop two algorithms for the design of the hybrid combiner based on switches and analyze the achieved spectral efficiency. Finally, we study the tradeoffs between power consumption, hardware complexity, and spectral efficiency for hybrid architectures based on phase shifting networks and switching networks. Numerical results show that architectures based on switches obtain equal or better channel estimation performance to that obtained using phase shifters, while reducing hardware complexity and power consumption. For equal power consumption, all the hybrid architectures provide similar spectral efficiencies.

    关键词： channel estimation,precoding,Millimeter wave,hybrid architecture,switches

    更新于2025-09-23 15:21:01

  • Harmonic Characterizations of Loaded Resonators for Waveguide Filters

    摘要： A new method of controlling and predicting the harmonic responses, for spurious-free window improvement of millimeter-wave bandpass filters, with complete mathematical derivation, is presented in this paper. This method relies on loading a transmission line resonator with inverters, permitting the increase/ decrease of the harmonics-to-fundamental ratios, for predetermined inverter coupling values. It is a universal method based on circuit models and mathematical theories, independent of the fabrication implementation; only typical bandpass filter inverters are necessary. It does not affect or include the design of input/ output resonator ports, with materials and dimensions, introducing the least design complexity, cf. other earlier approaches. Resonators and bandpass filters using substrate integrated waveguide technology are designed, simulated, fabricated, measured and validated. The derived models, simulations and measured results are in good agreement. The control of the harmonic performance is demonstrated by comparing the measurements of two bandpass filters fabricated with-waveguides, in the millimeter-wave band 27.9 to 29.5 GHz. The inverter-loaded resonators, is analyzed versus a conventional iris filter operating with the TE10 mode. The comparisons of the simulations and measurements of the two filters demonstrate experimentally the possibility of the systematic control of the harmonics-to-fundamental ratios of the proposed theoretical analysis.

    关键词： harmonic suppression,substrate integrated waveguide,Filters,higher-order modes,millimeter-wave,waveguide

    更新于2025-09-23 15:21:01

  • Groove Gap Waveguide Filter Based on Horizontally Polarized Resonators for V-Band Applications

    摘要： In this article, resonators based on air-?lled rectangular cavity consisting of one perfect magnetic conductor (PMC) wall and the rest of walls as the perfect electric conductor (PEC) are proposed. The proposed cavity can be engraved in the top or bottom metal plate of a gap waveguide structure, and the PMC wall is realized by the periodic metallic pins located within the gap waveguide geometry. The resonant frequency and electromagnetic (EM) ?eld distribution of the cavity are investigated, and it is shown that the electric ?eld is horizontally polarized with respect to the wave propagation direction. Two bandpass ?lters are designed by inserting the proposed cavity in the cutoff region of the gap waveguide, on the top and bottom plates. In the latter case, all pins are the same, and the cavities and coupling structure are easily implemented by engraving the top plate. Therefore, by using this concept, a common pin plate can be used to implement different passive millimeter-wave devices. For instance, three different ?lters working at 60, 65, and 70 GHz with a common bottom pin plate are designed and fabricated. The measured results show a minimum insertion loss of 1.4, 1.1, and 1.1 dB with 0.83%, 1.4%, and 1.8% fractional bandwidth for the three bandpass ?lter designs, respectively, with aluminum as metal.

    关键词： perfect magnetic conductor (PMC),Antenna system,millimeter-wave ?lter,gap waveguide

    更新于2025-09-23 15:21:01

  • A Compact 24x 24 Channel MIMO FMCW Radar System Using a Substrate Integrated Waveguide-Based Reference Distribution Backplane

    摘要： In this article a compact 120-GHz multiple-input-multiple-output (MIMO) imaging radar is presented. With a module size of only 25 cm, an angular resolution of less than 0.9? is obtained in elevation and azimuth direction using 24 transmitters and 24 receivers. The hardware is based on a SiGe:C MMIC technology and integrated into a modular frontend and backend structure. This article presents the overall hardware architecture of the RF-frontend, including a novel reference oscillator distribution concept and a connectorless board-to-board transition based on substrate integrated waveguides. A fully integrated backend is shown, and the entire radar system is evaluated experimentally and the imaging results are presented, demonstrating the large potential of the presented millimeter-wave 3-D imaging radar.

    关键词： multiple-input-multiple-output (MIMO) radar,substrate integrated waveguides (SIWs),Millimeter-wave sensing

    更新于2025-09-23 15:21:01

  • [IEEE 2019 International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS) - Taipei, Taiwan (2019.12.3-2019.12.6)] 2019 International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS) - Preliminary Design of a Waveguide-Fed Milimeter Wave Metasurface Antenna with LCD Controlled Array Factor for 5G User Equipment

    摘要： The millimeter wave 5G communication promises wide bandwidth for high data rate throughput, however the available area on cellular user equipment (UE) is quite limited, and 2 dimensional phased array occupies a large area and is fairly complicated. In this article we explore the possibility a waveguide-fed millimeter wave metasurface antenna for 28 GHz band. The element is a generic T-metasurface, and LCD control of array factor is suggested with a glass lens to focus the beam. A fan shape beam is generated from this antenna with maximum gain around 16.7 dB. This design may serve the 5G mmW communication with simpler structure to nearby small cell station.

    关键词： 5G,metasurface antenna,waveguide-fed,LCD control,millimeter wave

    更新于2025-09-23 15:21:01

  • Parameters extraction of photovoltaic models using triple-phase teaching-learning-based optimization

    摘要： Hybrid analog/digital multiple-input multiple-output architectures were recently proposed as an alternative for fully digital-precoding in millimeter wave wireless communication systems. This is motivated by the possible reduction in the number of RF chains and analog-to-digital converters. In these architectures, the analog processing network is usually based on variable phase shifters. In this paper, we propose hybrid architectures based on switching networks to reduce the complexity and the power consumption of the structures based on phase shifters. We define a power consumption model and use it to evaluate the energy efficiency of both structures. To estimate the complete MIMO channel, we propose an open-loop compressive channel estimation technique that is independent of the hardware used in the analog processing stage. We analyze the performance of the new estimation algorithm for hybrid architectures based on phase shifters and switches. Using the estimate, we develop two algorithms for the design of the hybrid combiner based on switches and analyze the achieved spectral efficiency. Finally, we study the tradeoffs between power consumption, hardware complexity, and spectral efficiency for hybrid architectures based on phase shifting networks and switching networks. Numerical results show that architectures based on switches obtain equal or better channel estimation performance to that obtained using phase shifters, while reducing hardware complexity and power consumption. For equal power consumption, all the hybrid architectures provide similar spectral efficiencies.

    关键词： switches,precoding,Millimeter wave,hybrid architecture,channel estimation

    更新于2025-09-23 15:21:01

  • Design and measurement of a 5G mmW mobile backhaul transceiver at 28 GHz

    摘要： High throughput and ultra low latency are the main requirements for fifth generation (5G) mobile broadband communications. Densely populated urban environments require utilization of previously underutilized millimeter wave frequency spectrum for higher data rates. The Ka-band, previously used in satellite applications, is of particular interest to terrestrial 5G mobile networks. New radio solutions are required for these frequencies, such as multiple wireless base stations organized in small cells and highly directional antennas to compensate for higher path loss. Wireless backhaul is predicted to be the most cost-effective and versatile solution to connect 5G base stations to the core network. Wireless backhaul enables flexible and easy installation of 5G base stations in ad hoc networks, supporting large crowd gatherings such as concerts and sports events. In this article, we present an architecture of a wireless backhaul transceiver, which operates on the 26.5–29.5-GHz band. The architecture described in this paper was implemented, and the performance of the receiver (Rx) array has been measured. We also present over-the-air antenna array measurement results using the Rx. The measurement results show that unequal Rx channel gains and antenna gains do not have a significant effect on the shape of the main lobe of the radiation pattern. We have measured a coherence gain of 2.7 dB from two Rx channels that is close to the theoretical value of 3.0 dB. We have achieved a conducted Rx EVM of better than 2% using a 100-MHz 16-QAM modulated signal at 26.5 GHz.

    关键词： Antenna pattern,Beamforming,Millimeter wave,Radio frequency,Transceiver,5G,Antenna array,Backhaul

    更新于2025-09-23 15:21:01

  • [IEEE 2018 IEEE 5G World Forum (5GWF) - Silicon Valley, CA, USA (2018.7.9-2018.7.11)] 2018 IEEE 5G World Forum (5GWF) - Multipath Propagation Analysis of 5G Systems at Higher Frequencies in Courtyard (Small Cell) Environment

    摘要： The main target of this paper is to study the propagation characteristics of an outdoor and indoor user utilizing 5G system at higher frequency in a courtyard surrounded by building walls i.e. small cell environment. This research work is carried out by doing 3D ray tracing simulations utilizing “sAGA” – a 3D ray tracing tool. Unlike the conventional cellular network frequencies, the considered frequencies in the scope of this work are 15 GHz, 28 GHz and 60 GHz. For simulation routes, the results are provided in the form of received signal strength. For static points, the results are presented in the form of power angular spectrum and power delay profile. The achieved simulation results show that an adequate outdoor and indoor service can be provisioned at the considered frequencies. However, it is challenging to provide services to indoor user at 60 GHz using an outdoor base station even in such a small cell environment.

    关键词： 3D ray tracing,multipath propagation,small cell,system performance,millimeter wave frequencies,5G

    更新于2025-09-23 15:21:01