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- 2018
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Absorber Characteristic Control by Equivalent Transformation Method of Material Constants
摘要： As mentioned in the previous chapters, demands for various EM-wave absorbers are rapidly increasing along with the trends toward complicated electromagnetic environments and the development of higher frequency communication equipment. Generally, it has been considered highly difficult to produce new EM-wave absorbers having a desired absorbing frequency and an absorbing characteristic. One reason for this is that realizing an optimum material constant satisfying the required characteristics becomes difficult when manufacturing an EM-wave absorber. That is, in the conventional method, it often becomes difficult to freely control parameters such as the mixing ratio of the EM-wave absorber’s raw materials, the firing temperature, the pressure, and the material compositions to realize the appropriate absorber. Furthermore, the problems of accurately measuring material constants and maintaining the accuracy of component sizes become important to the EM-wave absorber in high-frequency use, particularly in the millimeter or terahertz band.
关键词： equivalent transformation method of material constants (ETMMC),EM-wave absorbers,millimeter wave,terahertz band,high-frequency communication
更新于2025-09-19 17:13:59
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[IEEE 2019 Photonics North (PN) - Quebec City, QC, Canada (2019.5.21-2019.5.23)] 2019 Photonics North (PN) - Study of nonlinear optical refractive index in thin films formed by bloom gelatin and organic materials : (Indigo carmine dye and phenol red Ph indicator)
摘要： The presence of phase noise (PN) severely deteriorates the sensitivity and range of frequency-modulated continuous wave radar systems. Thus, characterization and continuous monitoring of the PN is indispensable, and its estimation is often employed directly on chip. Although many contributions investigate methods for PN estimation, almost all of them consider a continuous-wave (CW) input signal. Differently, in this paper, we aim to estimate the PN from a linear frequency modulated continuous wave (FMCW) signal. For that, we propose two methods utilizing a so-called artificial on-chip target and further digital signal processing. These methods are evaluated in real-time and are the first-known solutions to determine PN estimates during the operation of an FMCW radar transceiver. We prove our methods with both simulation and measurement results from a hardware prototype. Further, we present techniques to efficiently realize the concepts in digital hardware. Finally, we compare and trade off the proposed methods against computational complexity and performance. The novel techniques may be applied to arbitrary input frequencies and bandwidths, and do not require a reference-clock input.
关键词： Delay lines,millimeter-wave radar,phase noise (PN),(FMCW),estimation,monolithic microwave integrated circuits,frequency-modulated continuous wave
更新于2025-09-19 17:13:59
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Atomic Vapor Confined in a Nanoscale Geometry: From Mesoscopic to Collective Effects
摘要： Simulation data from a ray-tracing tool applied in specific urban environments in the 28-GHz band suggest that the utilization of arbitrary base station (BS) angles in a directional search procedure may not be of maximum benefit for users located in non-line-of-sight positions, because certain angles restrict the radio frequency illumination to a lower maximum power than from others. An appropriate selection of BS angles offers a potential power level benefit of greater than 2 dB in a defined number of consecutive measurements; however, this performance improvement appears to be conditioned by the severity of the existing street canyon propagation and the probability of the angle used. A simple ray tracing method is proposed to approximately identify the most effective BS angles that avoid power emissions in directions largely blocked by nearby buildings. The results indicate that prior site-specific information may be helpful, particularly for systems using analog beamforming.
关键词： Angle of arrival,millimeter wave,user equipment,ray tracing,non-line-of-sight,base station,radio frequency,beam direction
更新于2025-09-19 17:13:59
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[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) - Optically Pumped Mixing in Photonically Integrated Uni- Travelling Carrier Photodiode
摘要： We report the first demonstration of optically pumped mixing using a monolithically integrated photonic chip. On that chip, uni-traveling carrier photodiodes (UTC-PDs) were monolithically integrated with two lasers to generate the optical heterodyne that will drive the optically pumped mixing. The two DFB lasers wavelength spacing was tuneable from 70.5 GHz to 92.4 GHz. When an RF signal at 70 GHz was supplied to the UTC-PD with the optimum voltage bias, the UTC-PD successfully down-converted the RF signal to an intermediate frequency (IF) that was tuneable from 0.5 GHz to 16.4 GHz. These results demonstrate the potential of this photonic integrated circuit in spectroscopy, sensing and as millimeter wave wireless receivers.
关键词： photonic integrated circuit,heterodyne,millimeter wave,optically pumped mixing,uni-traveling carrier photodiode
更新于2025-09-19 17:13:59
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[IEEE 2019 Workshop on Recent Advances in Photonics (WRAP) - Guwahati, India (2019.12.13-2019.12.14)] 2019 Workshop on Recent Advances in Photonics (WRAP) - Simulation of Terahertz Propagation by TE Mode in Metal Dielectric Metal Waveguide
摘要： This paper presents a stable millimeter-wave power monitoring system for ECRH on EAST tokamak. The real-time power monitoring was realized based on power monitor miter bends. The ‘‘Exchange’’ method was proposed to monitor the re?ection power for RF protection. A cRIO-based signal process unit was designed, it is robust and has the response time of 1 μs. The power monitoring system was tested and the experimental results were discussed.
关键词： Labview,EAST tokamak,cRIO,millimeter wave power monitoring,ECRH
更新于2025-09-19 17:13:59
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[IEEE 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - Sarajevo, Bosnia and Herzegovina (2019.9.2-2019.9.4)] 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - Model of Fiber Optic Transmission System Based on the Red Pitaya
摘要： This paper presents numerical simulation results to study the impact of the co-existence between a fixed service (FS) system and 5G small cell networks at 28-, 38-, and 60-GHz millimeter-wave (mmWave) frequency bands. For this paper, two scenarios are considered: aggregation of interference from small cells into an FS receiver from base stations (BSs) to their associated user equipment (UE) (downlink) and the aggregation of cellular interference at the FS receiver from UEs to their associated BSs (downlink). Moreover, mmWave-specific propagation characteristics and attenuation factors are considered for a more precise simulation study. The simulation results determine how much interference rejection is required to protect the operation of FS. In addition, currently available mmWave modular antenna array (MAA) architectures are introduced. Based on the information, additional mmWave frequency sharing study is performed using the realistic MAA radiation patterns. Last, we compare and analyze the performance differences between ITU standard models and MAA solutions.
关键词： 28 GHz,frequency sharing study,modular antenna array,60 GHz,5G,Millimeter-wave,38 GHz
更新于2025-09-19 17:13:59
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Liquid Crystal-Based Enclosed Coplanar Waveguide Phase Shifter for 54a??66 GHz Applications
摘要： A 0–10 V bias voltage-driven liquid crystal (LC) based 0–180? continuously variable phase shifter was designed, fabricated, and measured with insertion loss less than ?4 dB across the spectrum from 54 GHz to 66 GHz. The phase shifter was structured in an enclosed coplanar waveguide (ECPW) with LC as tunable dielectrics encapsulated by a unified ground plate in the design, which significantly reduced the instability due to floating effects and losses due to stray modes. By competing for spatial volume distribution of the millimeter-wave signal occupying lossy tunable dielectrics versus low-loss but non-tunable dielectrics, the ECPW’s geometry and materials are optimized to minimize the total of dielectric volumetric loss and metallic surface loss for a fixed phase-tuning range. The optimized LC-based ECPW was impedance matched with 1.85 mm connectors by the time domain reflectometry (TDR) method. Device fabrication featured the use of rolled annealed copper foil of lowest surface roughness with nickel-free gold-plating of optimal thickness. Measured from 54 GHz to 66 GHz, the phase shifter prototype presented a tangible improvement in phase shift effectiveness and signal-to-noise ratio, while exhibiting lower insertion and return losses, more ease of control, and high linearity as well as lower-cost fabrication as compared with up-to-date documentations targeting 60 GHz applications.
关键词： tunable circuits and devices,true time delay,millimeter-wave,60 GHz,liquid crystal,phase shifter,enclosed coplanar waveguide
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - The Electrochemical Reactions in Crystalline Silicon Solar Modules
摘要： Millimeter-wave (mmWave) communication operated in frequency bands between 30 and 300 GHz has attracted extensive attention due to the potential ability of offering orders of magnitude greater bandwidths combined with further gains via beamforming and spatial multiplexing from multi-element antenna arrays. mmwave system may exploit the hybrid analog and digital precoding to achieve simultaneously the diversity, array and multiplexing gain with a lower cost of implementation. Motivated by this, in this paper, we investigate the design of hybrid precoder and combiner with sub-connected architecture, where each radio frequency chain is connected to only a subset of base station antennas from the perspective of energy efficient transmission. The problem of interest is a non-convex and NP-hard problem that is difficult to solve directly. In order to address it, we resort to design a two-layer optimization method to solve the problem of interest by exploiting jointly the interference alignment and fractional programming. First, the analog precoder and combiner are optimized via the alternating-direction optimization method where the phase shifter can be easily adjusted with an analytical structure. Then, we optimize the digital precoder and combiner based on an effective multiple-input multiple-output channel coefficient. The convergence of the proposed algorithms is proved using the monotonic boundary theorem and fractional programming theory. Extensive simulation results are given to validate the effectiveness of the presented method and to evaluate the energy efficiency performance under various system configurations.
关键词： Millimeter-wave communication,energy efficiency,interference alignment,analog precoding and combining,multiple-input multiple-output (MIMO) system
更新于2025-09-19 17:13:59
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Thin Film Photosensor Integrated on Planar Waveguide for Lab-an-Chip Applications
摘要： We report on high-frequency performance and temperature stability of zero-bias GaAsSb/InAlAs/InGaAs tunnel diodes for millimeter-wave detection in 220–330-GHz band. The average voltage sensitivity of 1400 V/W has been achieved in 0.8 × 0.8 μm2 mesa devices at room temperature. Measured current–voltage characteristics revealed a superior temperature stability of the devices compared with Schottky barrier diodes. The expected sensitivity variations over a temperature range from T = 17–300 K are 1.7 dB.
关键词： tunnel diode,tunneling,Backward diode,millimeter wave and terahertz detectors,semiconductor nanostructures
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 2nd International Conference on Renewable Energy and Power Engineering (REPE) - Toronto, ON, Canada (2019.11.2-2019.11.4)] 2019 IEEE 2nd International Conference on Renewable Energy and Power Engineering (REPE) - Perovskite solar cells-A futuristic approach
摘要： Simulation data from a ray-tracing tool applied in specific urban environments in the 28-GHz band suggest that the utilization of arbitrary base station (BS) angles in a directional search procedure may not be of maximum benefit for users located in non-line-of-sight positions, because certain angles restrict the radio frequency illumination to a lower maximum power than from others. An appropriate selection of BS angles offers a potential power level benefit of greater than 2 dB in a defined number of consecutive measurements; however, this performance improvement appears to be conditioned by the severity of the existing street canyon propagation and the probability of the angle used. A simple ray tracing method is proposed to approximately identify the most effective BS angles that avoid power emissions in directions largely blocked by nearby buildings. The results indicate that prior site-specific information may be helpful, particularly for systems using analog beamforming.
关键词： Angle of arrival,millimeter wave,user equipment,ray tracing,non-line-of-sight,base station,radio frequency,beam direction
更新于2025-09-19 17:13:59