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oe1(光电查) - 科学论文

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  • A Low-Profile, Directional, Ultrawideband Antenna

    摘要： A compact low pro?le, ultrawideband (UWB) antenna providing directional radiation pattern is proposed. The antenna is based on a modi?ed Vivaldi antenna, and is characterized by a three-dimensionally (3-D) bended structure. Each of the two radiation ?ns is capacitively loaded with an invert trapezoidal metallic plate at the end. In order to conveniently mount the antenna on the metal surface, a corrugated plate is added as a ground. Owing to the bended structure and capacitively loaded scheme, the antenna has a low pro?le of 0.216λm, where λm is the wavelength at the minimum operating frequency. The prototype of the antenna is fabricated and measured. The measured and simulated results show good agreement. The measured results show that the antenna has VSMR < 2.5 from 0.9 to 10 GHz and measured gain from 3.6 to 8.2 dBi.

    关键词： low pro?le antenna,directional radiation,ultrawide-band (UWB) antenna,three-dimensionally (3-D) structure

    更新于2025-09-04 15:30:14

  • [IEEE 2018 IEEE International Workshop on Electromagnetics: Applications and Student Innovation Competition (iWEM) - Nagoya, Japan (2018.8.29-2018.8.31)] 2018 IEEE International Workshop on Electromagnetics:Applications and Student Innovation Competition (iWEM) - A Compact Design of Reconfigurable Dual Band-Notched UWB Antenna

    摘要： This paper presents a compact design of UWB antenna with reconfigurable dual notch bands is proposed. The UWB antenna with a notch filter consists of a circular antenna and two-pairs of L-shaped resonators. To realize the notch characteristics in WLAN at 5.2 GHz and 5.8 GHz bands, a half wavelength of L-resonator is introduced in the radiating patch. A small T-shaped notch is etched in the partial ground plane to enhance the UWB bandwidth up to 7.513 GHz, which covers the frequency range from 3.048 - 10.561 GHz. An experimental proposed structure shows a good agreement with the simulated results. Furthermore, the proposed UWB antenna with notch filter has a compact size of 37.6 x 28 mm2. This proposed design can give an alternative solution for eliminating WLAN interferes in the UWB bands by designing the notch filter with a good tuning capability.

    关键词： band-notched,resonant frequency,Ultra-wideband (UWB),L-resonator

    更新于2025-09-04 15:30:14

  • WIDEBAND FREQUENCY SELECTIVE SURFACE WITH A SHARP BAND EDGE BASED ON MUSHROOM-LIKE CAVITY

    摘要： A wideband frequency selective surface (FSS) with a sharp band edge is proposed. The periodic cell includes a mushroom-like cavity and four L-type slots etched on the top and bottom conductor claddings of the cavity. The measured results show that the proposed FSS operates at X band with a 12.5% bandwidth (7.85–8.90 GHz), in which the insertion loss is less than 3 dB. Comparing with the FSSs based on substrate integrated waveguide cavity, the proposed FSS not only realizes high selectivity, but also realizes a 55.8% reduction in cell size.

    关键词： mushroom-like cavity,sharp band edge,frequency selective surface,wideband

    更新于2025-09-04 15:30:14

  • DESIGNING PLANE WAVE MODULATORS USING 1DPC NANOSTRUCTURE WITH R-GRIN DEFECT LAYER

    摘要： In this paper, we introduce plane wave modulators that are designed using one-dimensional photonic crystals (1DPC) containing radial gradient refractive index (r-GRIN) defect layers. Three kinds of r-GRIN materials with di?erent refractive index distribution functions are applied in numerical analysis. The properties of the phase and intensity of the transmitted plane wave beam through proposed structures are studied using the transfer matrix method. Radially-dependent defect modes, modulated phase and intensity are obtained according to the refractive index distribution functions. The results are predictable by regarding the Bragg condition and destructive interference, which are the origins of the photonic band gap (PBG). Due to the radial-dependency of the defect layer’s refractive index, the rays passing through di?erent transverse positions experience di?erent optical pathways. Therefore, the defect modes and transmitted spectrum (phase and amplitude) vary transversely. This study demonstrates another ability of the arti?cial PC structures to design plane wave modulators and manipulate its phase and intensity.

    关键词： radial gradient refractive index,transfer matrix method,one-dimensional photonic crystals,plane wave modulators,photonic band gap

    更新于2025-09-04 15:30:14

  • NUMERICAL INVESTIGATION ON THE SPECTRAL PROPERTIES OF ONE-DIMENSIONAL TRIADIC-CANTOR QUASI-PERIODIC STRUCTURE

    摘要： We numerically investigate the optical spectra of a photonic band gap material realized by one-dimensional Triadic-Cantor quasi-periodic structure. The studied system is composed of two elementary layers H and L with refractive indices nL = 1.45 (SiO2) and nH = 2.3 (T iO2), respectively. Analytical calculations using a trace and antitrace maps approach have been used to ?nd the re?ection and transmission theoretical expressions in visible range under quarter wavelength condition. In our results we present the e?ect of iteration order of Triadic-Cantor sequence on the optical properties of these multilayer systems, namely the photonic band gap behavior and the optical windows presence, which makes this type of structures good candidates for interesting applications in the ?eld of the nano-optical Engineering.

    关键词： trace and antitrace maps,Triadic-Cantor,optical properties,quasi-periodic structure,photonic band gap

    更新于2025-09-04 15:30:14

  • Influência do Strain e da Intera??o Spin-órbita em um Ponto Quantico Cilíndrico

    摘要： In this work study how the strain and spin-orbit Rashba interaction type affect the energy levels of the conduction band in a cylindrical quantum dot, using the 2x2 method k●p. The results show that the spin-orbit interaction strongly influences the energy levels of lifting the degeneracy even in zero magnetic field, while the strain compressing the levels enhance the Rashba interaction effects. In this context, the intraband optic absorption becomes a useful tool to study the effects of spin-orbit interaction and the strain on the electron energy levels.

    关键词： k●p method,Conduction Band,Quantum dots,Strain,Spin-orbit Rashba interaction

    更新于2025-09-04 15:30:14

  • COMPACT HIGH-SELECTIVITY DUAL/TRI-BAND BANDPASS FILTERS FOR WLAN APPLICATIONS

    摘要： This paper presents compact dual/tri-band bandpass ?lters (BPFs) with controllable frequency and high selectivity for WLAN applications. A stepped impedance resonator with a shorting stub and a uniform impedance resonator with an open stub are applied in the designs. Several techniques that can generate transmission zeros are combined to improve the frequency selectivity. The resonators and the proposed ?lters are characterized by full-wave simulations. To validate the design strategies, a dual-band BPF centered at 2.4 GHz and 5.2 GHz was ?rst designed. With a minor modi?cation, a tri-band BPF centered at 2.4 GHz, 5.2 GHz and 5.8 GHz was then developed. Both simulations and measurements were carried out to demonstrate the e?ectiveness of the designs. Good agreements are achieved.

    关键词： Dual/Tri-Band,Bandpass Filters,WLAN Applications,Compact,High-Selectivity

    更新于2025-09-04 15:30:14

  • A NOVEL DUAL-BAND SIW FILTER WITH HIGH SELECTIVITY

    摘要： A novel dual-band substrate integrated waveguide (SIW) ?lter with multiple transmission zeros and good out-of-band rejection performance is presented in this paper. For this purpose, an orthogonal input/output (I/O) feeding structure directly connected to the substrate integrated waveguide (SIW) cavity is designed to split the resonant frequencies of the degenerate pair of mode. The ?lter can be modeled with a multi-path circuit formed by three modes (TE101, TE201 and TE102 modes) and weak cross coupling between I/O ports, thereby producing three transmission zeros which make the dual-band high selectivity. The o?set of the input/output ports shifts the second transmission zero to a lower frequency from the upper passband. Several ?lter prototypes are designed and fabricated for demonstration, and the measured results validate the new structure for high selectivity applications.

    关键词： high selectivity,substrate integrated waveguide (SIW),dual-band,orthogonal input/output feeding structure,transmission zeros

    更新于2025-09-04 15:30:14

  • ANALYSIS OF WIDE BAND SCATTERING FROM OBJECTS USING THE ADAPTIVE IMPROVED ULTRA-WIDE BAND CHARACTERISTIC BASIS FUNCTIONS

    摘要： The improved ultra-wide band characteristic basis function method (IUCBFM) is an efficient approach to analyze the wide-band scattering problems because the improved ultra-wide characteristic basis functions (IUCBFs) can be reused for any frequency sample in the range of interest. However, the number of the IUCBFs constructed at the highest frequency point is excessive, and the computational complexity will be increased when applying the same number of IUCBFs at the lower frequency points. To mitigate this problem, an adaptive IUCBFs construction method is presented which can decrease the computational complexity at the lower frequency points. In the proposed method, the given frequency band is adaptively divided into multiple sub-bands in consideration of the number of the IUCBFs. The adaptive IUCBFs are obtained at the highest frequency point in each sub-band, which leads to smaller number of IUCBFs and significant reduction of solver time at lower frequency band. The numerical results have demonstrated the accuracy and efficiency of the proposed method.

    关键词： characteristic basis function method,computational complexity,radar cross section,wide-band scattering,adaptive construction

    更新于2025-09-04 15:30:14

  • [Smart Innovation, Systems and Technologies] Information and Communication Technology for Intelligent Systems Volume 107 (Proceedings of ICTIS 2018, Volume 2) || Performance Booster Electrical Drain SiGe Nanowire TFET (EDD-SiGe-NW-TFET) with DC Analysis and Optimization

    摘要： In this paper, new concept for TFET nanowire is proposed to eliminate the issues aroused in MOSFET due to continuous scaling the device dimensions. Proposed device uses the concept of electrically doping as well as physically doping. Other than that low band gap material, silicon germanium (SiGe), is used at source region and high k dielectric is used at source–channel interface to improve the performance of the proposed structure. Simulation is done using 3D TCAD ATLAS simulator, and result validates that the proposed device is suitable for low power application. Furthermore, simulation is done for the different diameters and channel lengths for optimization.

    关键词： Electrical drain,Nanowire TFET,Low band gap,Hetero dielectric

    更新于2025-09-04 15:30:14