- 标题
- 摘要
- 关键词
- 实验方案
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Medium Power Application of a Four-Port Reflectometer
摘要： This paper describes an application of a four-port reflectometer system to measure the reflection coefficient of a terminal load from 1 GHz to 2.5 GHz at about 150 W power level. The scattering parameters of the four-port reflectometer measured at low power have been experimentally proved to be applicable at medium power. The measurement results of the four-port reflectometer are presented and analyzed. This measurement method can be used at higher power level.
关键词： Medium Power,Four-Port Reflectometer,reflection coefficient,Directional Coupler
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Shenzhen, China (2018.9.4-2018.9.7)] 2018 IEEE 3rd Optoelectronics Global Conference (OGC) - Non-volatile Optical Switch Based on a GST-Loaded Directional Coupler
摘要： We present a non-volatile optical switch based on a directional coupler comprising a silicon-Ge2Sb2Te5 (GST) hybrid waveguide. The non-volatility of GST makes it attractive for reducing static power consumption in optical switching. Experimental results show that the optical switch has an extinction ratio of >20 dB in the bar state and >25 dB in the cross state around 1578 nm wavelength. The insertion loss is 2 dB and 7 dB for the bar and cross states, respectively.
关键词： directional coupler,silicon photonics,phase change material
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Chengdu, China (2018.3.26-2018.3.28)] 2018 IEEE International Conference on Computational Electromagnetics (ICCEM) - Dielectric Coupler with Bandpass Filtering Response
摘要： The conventional rectangular dielectric resonator usually can only support single mode operation. Additional conductor is loaded to introduce new mode and control the higher order modes for multi-mode operation. Based on this conductor-loaded resonator, a new quadrature coupler is proposed with bandpass filtering response. For validation, a 3 dB dielectric coupler operating at 3. 5 GHz was designed, fabricated and measured. Besides the desired equal power quadrature power division, additional bandpass filtering functionality has been implemented. Two transmission zeros have been generated for good selectivity. Good agreement between simulation and measurement has been achieved.
关键词： arbitrary coupling coefficients,Dielectric resonator,filtering,coupler
更新于2025-09-10 09:29:36
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Wavelength-Flattened Directional Coupler Based Mid-Infrared Chemical Sensor Using Bragg Wavelength in Subwavelength Grating Structure
摘要： In this paper, we report a compact wavelength-flattened directional coupler (WFDC) based chemical sensor featuring an incorporated subwavelength grating (SWG) structure for the mid-infrared (MIR). By incorporating a SWG structure into directional coupler (DC), the dispersion in DC can be engineered to allow broadband operation which is advantageous to extract spectroscopic information for MIR sensing analysis. Meanwhile, the Bragg reflection introduced by the SWG structure produces a sharp trough at the Bragg wavelength. This sharp trough is sensitive to the surrounding refractive index (RI) change caused by the existence of analytes. Therefore, high sensitivity can be achieved in a small footprint. Around fivefold enhancement in the operation bandwidth compared to conventional DC is achieved for 100% coupling efficiency in a 40 μm long WFDC experimentally. Detection of dichloromethane (CH2Cl2) in ethanol (C2H5OH) is investigated in a SWG-based WFDC sensor 136.8 μm long. Sensing performance is studied by 3D finite-difference time domain (FDTD) simulation while sensitivity is derived by computation. Both RI sensing and absorption sensing are examined. RI sensing reveals a sensitivity of ?0.47% self-normalized transmitted power change per percentage of CH2Cl2 concentration while 0.12% change in the normalized total integrated output power is realized in the absorption sensing. As the first demonstration of the DC based sensor in the MIR, our device has the potential for tertiary mixture sensing by utilizing both changes in the real and imaginary part of RI. It can also be used as a broadband building block for MIR application such as spectroscopic sensing system.
关键词： subwavelength grating,waveguide coupler,nanophotonics,photonics sensors,mid-infrared
更新于2025-09-10 09:29:36
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Shape-optimized multi-mode interference for a wideband visible light coupler
摘要： We developed a wideband visible light coupler based on multi-mode interference (MMI) using silica planar lightwave circuit (PLC) technology. The MMI shape was designed by using analytical and numerical optimization techniques to expand the transmission range around the target wavelength. We used this method for green (G) and blue (B) coupler to expand G and B transmission range. The transmittances of the fabricated coupler designed by the hybrid design method were ?1.5 to ?1.0 dB at wavelengths of 430 to 465 nm and ?0.5 to ?0.1 dB at wavelengths of 508 to 625 nm, respectively. The coupler length is about 1 mm without an input/output circuit. The coupler can be used for the whole wavelength range of G and B as a GB coupler.
关键词： Displays,Multimode interference,Wavelength division multiplexing,RGB coupler,Optical waveguides
更新于2025-09-10 09:29:36
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Three-mode multiplexer and demultiplexer utilizing trident and multimode couplers
摘要： In this paper, a simultaneous three-mode silicon (de)multiplexer using a trident coupler and a 3×3 multimode interference (MMI) is presented. The fundamental (TE0), first-order (TE1), and second-order (TE2) modes at the input are successfully demultiplexed and converted to three uniform fundamental modes (TE0) at the output ports. The device is designed and optimized by numerical simulation using three-dimensional beam propagation method together with effective index method. The three-mode (de)multiplexing is achieved over the whole C-band with small insertion loss (<0.9 dB) and crosstalk (<?17 dB). The proposed device also features with a small footprint (5 μm×400 μm) and a large fabrication tolerance against chip-size variations while maintaining the desired optical performance.
关键词： silicon photonics,Mode-division multiplexing,Y-junction coupler,planar lightwave circuits,mode conversion,multimode interference coupler
更新于2025-09-09 09:28:46
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Surface grafting modification of titanium dioxide by silane coupler KH570 and its influences on the application of blue light curing ink
摘要： A series of reactive TiO2 pigments with olefinic double-bonds were prepared by grafting modification of silane coupler KH570 to be covalently anchored in the blue-light curing film, which improved the color fastness to crocking of the printed fabrics significantly. Effects of KH570 concentrations on particle size, surface wettability and dispersing stability of KH570-TiO2 pigments, photo-polymerization of KH570-TiO2 bule-light curing inks and tensile properties of curing films were investigated. Color fastness to crocking of KH570-TiO2 pigment on cotton fabric was explored. Results showed that compared to the native TiO2, all the properties of KH570-TiO2 improved. With the increases of KH570 concentrations, the grafting degrees of KH570-TiO2 had gradual increase. The surface hydrophobicity and dispersion stability of KH570-TiO2 pigments, photo-polymerization of KH570-TiO2 blue-light curing ink and tensile properties of curing films enhanced, especially those of 12KH570-TiO2~20KH570-TiO2 the best. Within the concentrations of KH570 12～20 wt %, the printed fabrics had dry/wet color fastness to crocking no less than 4 grades.
关键词： printing ink,grafting,blue-light curing,Titanium dioxide,silane coupler
更新于2025-09-09 09:28:46
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Theory and Design of a Retrodirective Rat-Race-Based RFID Tag
摘要： Movement towards mm-wave backscatter communications in radio-frequency identification (RFID) systems necessitates seeking designs that compensate for the path loss introduced by the radio channel. A viable, simple, and power-efficient solution is to equip RFID tags with retrodirective arrays, which guarantee reflection with maximal gain in the direction of incidence. In this paper, we build upon a previous work to design and implement an original retrodirective tag in which its feeding network is a properly-terminated rat-race coupler. We start by deriving the required terminations that ensure retrodirectivity. Then, we build a retrodirective tag and experimentally compare its radar cross section to that of a single-antenna tag. The measurements reveal that the radar cross section of the proposed retrodirective tag is, on average, approximately 6 dB more than that of a single-antenna tag while both tags have the same field-of-view. From the promising results in this paper, the proposed design is a potential candidate for next-generation microwave and mm-wave RFID tags because it is compatible with low-power reflection amplifiers (e.g., tunnel diodes), it can implement multiple modulation schemes without changing the circuit layout, and it can be implemented using only a single RF switch.
关键词： multi-modulation RFID tags,Retrodirective arrays,rat-race coupler
更新于2025-09-09 09:28:46
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Uneven-to-Even Power Distribution for Maintaining High Efficiency of Dual-Linearly Polarized Rectenna
摘要： The RF-to-dc power conversion ef?ciency (PCE) of the conventional dual-linearly polarized (DLP) rectenna often suffers from uneven RF power received by two ports of the DLP antenna, which is caused by a tilt angle between the linearly polarized incidence and the two polarizations of the antenna. In this letter, a hybrid coupler is employed to redistribute the uneven power from the DLP antenna to two even power distributions for a successive modi?ed Greinacher charge pump (GCP). Thus, a high RF-to-dc PCE of the modi?ed GCP can be maintained. Both theoretical analysis and experiment validate the proposed power distribution scheme, which maintains a stable high PCE of a DLP rectenna irrespective of polarization tilt angle. The proposed scheme is, thus, suitable for high-ef?ciency wireless power transfer.
关键词： wireless power transfer (WPT),hybrid coupler,Dual-linearly polarized (DLP) rectenna
更新于2025-09-09 09:28:46
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A NEW EQUAL POWER QUADRATURE BRANCH LINE COUPLER FOR DUAL-BAND APPLICATIONS
摘要： We present a new equal power quadrature branch line coupler (BLC) for dual-band applications in this paper. A new topology of the dual-band quarter wavelength transmission lines (TL) with the derivation of design equations is also introduced. The proposed BLC is designed using Advanced Design System (ADS) and fabricated on Rogers 5870 at 0.9 GHz and 2.4 GHz center frequencies. The design approach for the proposed dual-band BLC is endorsed by the simulated and measured results. A comparative analysis of this BLC with the previous BLCs is also carried out.
关键词： Advanced Design System,quarter wavelength transmission lines,equal power quadrature branch line coupler,Rogers 5870,dual-band applications
更新于2025-09-09 09:28:46