- 标题
- 摘要
- 关键词
- 实验方案
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Single-Layer Multi-Via Loaded CRLH Leaky-Wave Antennas for Wide-Angle Beam Scanning with Consistent Gain
摘要： Achieving continuous backward-to-forward wide-angle beam scanning with consistent gain by employing composite right/left-handed leaky-wave antennas (LWAs) is reported. For structural and design simplicity, a single-layer 1-D structure is considered in which each unit cell consists of a patch shorted centrally to the ground plane. It was found that, when using only one via at the center of a unit cell, a continuous beam scan requires a large diameter via when all other parameters remain unchanged. To eliminate this limitation while maintaining a single-layer structure, novel unit cells are proposed using multiple vias in each unit cell. An LWA design for continuous beam scan with three vias in each unit cell is investigated and the results show good performance and design flexibility. A prototype antenna has been realized, and the measured results show that the antenna can scan the radiation beam continuously in a wide range, from ?60° to +66° with a consistent gain. The measured gain variation within the scan range is only 2.9 dB, and the 3dB gain bandwidth is 58.6%.
关键词： single-layer,leaky-wave antenna (LWA),backward and forward,consistent gain,composite right/left-handed (CRLH),Beam scanning
更新于2025-09-23 15:23:52
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X/Ku Dual-Band Single-Layer Reflectarray Antenna
摘要： X/Ku dual-band single-layer reflectarray antenna is presented. The proposed reflectarray antenna operates in two separated bands with separate feeds. The reflectarray element is composed of a split ring with two phase delay lines and a phoenix patch. The split ring and phoenix patch are designed for operation at X- and Ku- bands, respectively. The split ring is selected as the lower frequency element because of the large enough internal space. The phase shift of these two elements does not depend on variation of external size, which provides a feasible method for designing dual-band elements. The lower-band phase shift is obtained by changing the rotation angle of the phase delay lines. The movement of the inner loop of phoenix patch provides the required phase shift for the higher band. The proposed element realizes 360° phase shift range in both bands. The reflectarray is fabricated and measured to validate the design. The measured gains are 22.9 dBi at 8.5GHz with aperture efficiency of 40%, and 28.8 dBi at 16GHz with aperture efficiency of 44.8%. Besides, the 1 dB gain bandwidths are 20.5%(7.9GHz-9.7GHz) at lower band and 13.3 %(14.7GHz-16.8GHz) at higher band.
关键词： reflectarray antenna,single layer,dual band
更新于2025-09-23 15:23:52
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Chemical Vapor Deposition for Nanotechnology || Atmospheric Pressure Chemical Vapor Deposition of Graphene
摘要： Recently, graphene has gained significant interest owing to its outstanding conductivity, mechanical strength, thermal stability, etc. Among various graphene synthesis methods, atmospheric pressure chemical vapor deposition (APCVD) is one of the best syntheses due to very low diffusivity coefficient and a critical step for graphene-based device fabrication. High-temperature APCVD processes for thin film productions are being recognized in many diversity technologies such as solid state electronic devices, in particular, high quality epitaxial semiconductor films for silicon bipolar and metal oxide semiconductor (MOS) transistors. Graphene-based devices exhibit high potential for applications in flexible electronics, optoelectronics, and energy harvesting. In this chapter, recent advances of APCVD-based graphene synthesis and their related applications will be addressed.
关键词： large-scale,atmospheric pressure chemical vapor deposition (APCVD),graphene,bilayer graphene (BLG),single-layer graphene (SLG),atmosphere pressure
更新于2025-09-23 15:22:29
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Low Voltage Graphene-Based Amplitude Modulator for High Efficiency Terahertz Modulation
摘要： In this paper, a high-e?ciency terahertz amplitude modulation device based on a ?eld-e?ect transistor has been proposed. The polarization insensitive modulator is designed to achieve a maximum experimental modulation depth of about 53% within 5 V of gate voltages using monolayer graphene. Moreover, the manufacturing processes are inexpensive. Two methods are adopted to improve modulation performance. For one thing, the metal metamaterial designed can e?ectively enhance the electromagnetic ?eld near single-layer graphene and therefore greatly promote the graphene’s modulation ability in terahertz. For another, polyethylene oxide-based electrolytes (PEO:LiClO4) acts as a high-capacity donor, which makes it possible to dope single-layer graphene at a relatively low voltage.
关键词： solid electrolyte,terahertz,single-layer graphene,transmittance,metamaterial,amplitude modulation,?eld-e?ect transistor
更新于2025-09-23 15:21:01
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Single-Layer Dual-Band Balanced Substrate- Integrated Waveguide Filtering Power Divider for 5G Millimeter-Wave Applications
摘要： A single-layer substrate-integrated waveguide (SIW) filtering power divider (FPD) with fully differential operation at 28 and 39 GHz is proposed in this letter. This FPD consists of three SIW cavities where the differential and common modes of each cavity were properly designed to form three-pole dual passbands, facilitate deployment of isolation resistors, and introduce transmission zeros while attaining high in-band common-mode rejection. To improve the output return loss and isolation in dual bands, a novel and simple approach to find the proper location of isolation resistors is presented. At operating frequencies, the measured differential-mode input or output return loss, minimum insertion loss, isolation, and common-mode suppression are >14.1 dB, <(3 + 2.2) dB, >14.9 dB, and >30.3 dB, respectively. The amplitude and phase imbalances between outputs are <0.48 dB and <4.2?, respectively.
关键词： balanced,dual-band,isolation resistor,common-mode rejection,substrate-integrated waveguide (SIW),differential,single-layer,mixed-mode,filtering power divider (FPD),5G
更新于2025-09-23 15:21:01
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Low-profile wideband circularly polarised single-layer metasurface antenna
摘要： A novel low-pro?le single-fed circularly polarised single-layer metasurface antenna for wideband operation is proposed in this Letter. The metasurface antenna consists of nine unit cells arranged in a 3 × 3 layout. Four slits are incorporated into four of them, respectively, to form two orthogonal currents with 90° phase difference; hence, circularly polarised ?elds are excited. Moreover, a modi?ed L-type slot is etched on the middle lattice to improve impedance bandwidth and axial ratio performance. The proposed dielectric-?lled (?r = 3.5, tan δ = 0.001) antenna with a low pro?le of 0.038λ0 (λ0 is the working wavelength at 5.7 GHz in free space) achieves about 18.0% measured ?10 dB impedance bandwidth. The measured 3-dB axial ratio bandwidth of the proposed antenna is about 12.8% (5.35–6.08 GHz) with a broadside gain of more than 6.9 dBi.
关键词： low-profile,metasurface antenna,wideband,circularly polarised,single-layer
更新于2025-09-23 15:21:01
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First Principles Study on Magnetic and Optical Properties of Single Layer CrSi<sub>2</sub>
摘要： According to first-principle based on the density functional theory, the magnetic and optical properties of single layer CrSi2 are calculated and analyzed by plane wave pseudo potential method. The band structure, density of state, optical absorption spectra, reflectivity and energy loss function of single layer CrSi2 are obtained. The results show that single layer CrSi2 has the properties of metal and magnetism. The calculations of optical properties of single layer CrSi2 material deduce that it can absorb photons which belong to visible to ultraviolet region, even in far-infrared and far-ultraviolet regions. Single layer CrSi2 has a good optical permeability to photon (with energy from 13 to 40eV), which shows that single layer CrSi2 is suitable for optoelectronic devices, especially in infrared and vacuum ultraviolet detection applications.
关键词： single layer CrSi2,first-principles,electronic structure,optical properties
更新于2025-09-19 17:15:36
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Configuration Examples of the <scp>EM</scp> ‐wave Absorber
摘要： In recent years, along with increase in various kinds of demands on the communication environment has become communication systems, more complicated. As a result, the introduction of electromagnetic (EM)-wave absorbers is required in each technical field, especially from the viewpoint of preventing interference and mutual interaction. Regarding the pyramid-type absorber, it is widely used and popularized in anechoic chambers; these technologies have reached a high completion degree. For this reason, in this chapter, EM-wave absorber characteristics are addressed, such as those of the quarter-wavelength absorber, single-layer absorber, and two-layer absorber, while touching upon the implementation principle.
关键词： anechoic chambers,single-layer absorber,EM-wave absorber,two-layer absorber,quarter-wavelength absorber
更新于2025-09-19 17:13:59
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An X-band single-layer waveguide directional filter with compact size and low insertion loss
摘要： A novel waveguide directional ?lter with compact-size and low insertion loss is proposed in this letter. The basic structure consists of a pair of rectangular waveguides placed parallel to each other along their narrow side and two identical band-pass ?lters connect them via two coupling slots. For easy of fabrication and assembling, all the band-pass ?lters and wave-guides have a uniform height, that is all the components of the directional ?lter are in a single-layer waveguide. It is easy machining by standard computer numerical controlled (CNC) techniques to match the requirement for low cost. For veri?cation purpose, an X-band single-layer waveguide directional ?lter has been manufactured and measured. The measured results show a insertion loss better than 0.1 dB, a return loss lower than ?17.5 dB and a isolation better than ?22.5 dB, good band-pass and band-elimination responses are also obtained over the frequency range from 7.25 GHz to 9.75 GHz. The good agreement has been found between the simulated and measured results.
关键词： waveguide directional ?lter,X-band,compact-size,low insertion loss,single-layer
更新于2025-09-19 17:13:59
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Electromagnetic Wave Absorbers (Detailed Theories and Applications) || Methods of Absorber Analysis
摘要： The pyramidal absorbers described in Chapter 1 in the classification of electromagnetic (EM)-wave absorber appearance have been extensively used in anechoic chambers and have already reached sufficient technical achievement levels. In addition, various design methods have been proposed so far regarding these pyramidal absorbers, and their design methods have already been broadly established from aspects of both analysis and actual measurement, as discussed in Chapter 1 [1–5]. On the other hand, various application fields have been expected for flat-type absorbers along with the rapid progress of future communication environments. In view of these situations, in this book we mainly focus on single-layer plate-type absorbers and a multilayer-type absorber composed of flat plate absorbers.
关键词： anechoic chambers,single-layer plate-type absorbers,electromagnetic wave absorbers,flat-type absorbers,multilayer-type absorber
更新于2025-09-19 17:13:59