Novel Multifunctional Dual-band Coupled-Line Coupler with Reuse of Low-Frequency Trans-Directional and High-Frequency Contra-Directional Functions

2020 ◽  
pp. 1-1
Author(s):  
Yifan Zhang ◽  
Yongle Wu ◽  
Weimin Wang ◽  
Yuhao Yang ◽  
Li Ma
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Dual Band ◽  
Coupled Line

Dual-band low-profile planar antenna for mobile communication application

2015 ◽  
Vol 9 (2) ◽  
pp. 447-452 ◽  
Author(s):  
Xi-Wang Dai ◽  
Tao Zhou ◽  
Bo-Ran Guan
Keyword(s):  
Frequency Band ◽  
Mobile Communication ◽  
High Frequency ◽  
Microstrip Line ◽  
Low Frequency ◽  
Dual Band ◽  
Planar Antenna ◽  
Frequency Resonance ◽  
Low Profile ◽  
High Frequency Resonance

A novel dual-band planar antenna with a low profile for mobile communication system is proposed in this paper. The antenna is composed of one shorted patch with two radiating notches for low frequency resonance and one square patch for high frequency resonance. The low profile is achieved via the shorting patch, which introduces the parallel electrical field between the reflector and antenna. A step-impedance microstrip line is used to feed the antenna. The coupling between the square patch and microstrip line cancels out the inductance of shorting probe, which increases the working bandwidth of proposed antenna. A prototype with a low profile of 0.0286λ is fabricated and measured. The antenna achieves dual impedance bandwidths of 1.6% for the low frequency band and 60% for the high frequency band, covering the frequency range 851–865 MHz and 1.97–3.65 GHz, respectively. The measured results show good agreements with the simulated ones.

FREQUENCY-TUNABLE DUAL-BAND PRINTED ANTENNA EQUIPPED WITH COAXIALSPLIT BALANCING UNIT

2019 ◽  
pp. 60-64
Author(s):  
S. A. Alekseytsev ◽  
A. P. Gorbachev
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Dipole Antenna ◽  
Dual Band ◽  
Radiation Characteristics ◽  
High Frequency Response ◽  
Maximum Value ◽  
Linear Behavior ◽  
Lumped Elements ◽  
Frequency Tunable

In this paper, we present initial design of dual-band dipole antenna which able to perform when shifting high frequency band by inserting of inductive element between high-, and low-frequency dipole arms. Responses of high frequency and bandwidth at –10 dB level on the inductivity are presented in the paper. The maximum value of inductivity to be inserted is about hundreds of nH, hence, it can be implemented by microstrip lines. It is also possible to use lumped elements. Approximations of such responses with polynomials power two and lower are presented in the paper. It is shown, that the bandwidth of the S11 below –10 dB high frequency response has approximately linear behavior, so that can be used when carrying out experimental verifying of the numerical simulations. When simulating radiation characteristics the Russian standard FAF‑4D substrate was used, which can operate at frequencies up to 8–10 GHz.

Dual-band slot microstrip patch antennas with dual-radiation modes for wireless communication

2019 ◽  
Vol 12 (2) ◽  
pp. 155-162
Author(s):  
Guangwei Yang ◽  
Jianying Li ◽  
Jiangjun Yang ◽  
Zijian Xing
Keyword(s):  
Wireless Communication ◽  
Frequency Band ◽  
High Frequency ◽  
Communication Systems ◽  
Low Frequency ◽  
Dual Band ◽  
High Frequency Band ◽  
Radiation Beam ◽  
Microstrip Patch ◽  
Dual Band Antenna

AbstractIn this paper, a novel compact dual-band microstrip patch antenna with dual-radiation modes is investigated. The proposed antenna consists of a rectangular ground plane, a U-shaped feed probe, and an H-shaped slot radiating patch. By adjusting the size of these structures, a dual-band antenna can be obtained. In the low-frequency band, the antenna can radiate one radiation beam with high gain. In the high-frequency band, the antenna can achieve monopole-like radiation pattern. Therefore, an antenna prototype is fabricated and measured for validation. Good agreement between the simulated and measured results is observed in this paper. The antenna's operating frequency ranges are 3.6–3.85 GHz in the low-frequency band and 5.1–6.1 GHz in the high-frequency band with the reflection coefficient less than −10 dB. At 3.7 GHz, the antenna radiate one beam with 8.8 dBi realized gain. At 5.5 GHz, it exhibits dual-radiation beams directed to −48 and 48° with 5.6 and 5.5 dBi realized gain in the xoz-plane and −48 and 48° with 2.9 and 3.0 dBi realized gain in the yoz-plane. Therefore, the proposed antenna is a good candidate for wireless communication systems.

Narrow-dual-band perfect absorption plasmonic sensor in metamaterials based on the coupling of two resonators

2016 ◽  
Vol 25 (03) ◽  
pp. 1650027 ◽  
Author(s):  
Ruiping Bai ◽  
Xing Ri Jin ◽  
Ying Qiao Zhang ◽  
Shou Zhang ◽  
Youngpak Lee
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Peak Position ◽  
Dual Band ◽  
Resonant Peak ◽  
Perfect Absorber ◽  
Plasmonic Sensor ◽  
Perfect Absorption ◽  
Metal Insulator Metal ◽  
Sensitive Sensor

We propose a narrow-dual-band metamaterial perfect absorber (MPA) made of metal-insulator-metal multilayer composite based on the coupling of two resonators. The absorptance of dual resonant peak all exceeding 95% at [Formula: see text][Formula: see text]nm and 98% at [Formula: see text][Formula: see text]nm ([Formula: see text] is the length of ‘left’–‘right’ pair), respectively, where the full absorption width at half-maximum is about 3% (low frequency) and 5% (high frequency). The narrow distance of dual resonant peak is 31.4[Formula: see text]THz together with 43.6[Formula: see text]THz when [Formula: see text][Formula: see text]nm and 290[Formula: see text]nm, respectively. In addition, we demonstrate that the MPA can work as a sensitive sensor for refractive index sensing. The figure of merit FOM* reaches 197.7 (low frequency) and 274.8 (high frequency) when [Formula: see text][Formula: see text]nm. The narrow-dual-band peak position can be controlled by changing [Formula: see text] as well.

scholarly journals Robust Watermarking through Dual Band IWT and Chinese Remainder Theorem

2018 ◽  
Vol 7 (4) ◽  
pp. 561-569
Author(s):  
Prajanto Wahyu Adi ◽  
Farah Zakiyah Rahmanti ◽  
Edy Winarno
Keyword(s):  
Image Quality ◽  
High Frequency ◽  
Chinese Remainder Theorem ◽  
Low Frequency ◽  
Dual Band ◽  
Gaussian Filter ◽  
Robust Watermarking ◽  
Good Image Quality ◽  
Jpeg2000 Compression ◽  
Watermarking Scheme

CRT was a widely used algorithm in the development of watermarking methods. The algorithm produced good image quality but it had low robustness against compression and filtering. This paper proposed a new watermarking scheme through dual band IWT to improve the robustness and preserving the image quality. The high frequency sub band was used to index the embedding location on the low frequency sub band. In robustness test, the CRT method resulted average NC value of 0.7129, 0.4846, and 0.6768 while the proposed method had higher NC value of 0.7902, 0.7473, and 0.8163 in corresponding Gaussian filter, JPEG, and JPEG2000 compression test. Meanwhile the both CRT and proposed method had similar average SSIM value of 0.9979 and 0.9960 respectively in term of image quality. The result showed that the proposed method was able to improve the robustness and maintaining the image quality.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

SEM image sharpness analysis

1996 ◽  
Vol 54 ◽  
pp. 142-143
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Quantitative Information ◽  
Primary Electron ◽  
Image Sharpness ◽  
Critical Dimensions ◽  
Sem Image ◽  
Frequency Changes ◽  
Electron Microscopes ◽  
Scanning Electron

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. The industry requires that an automated instrument must be routinely capable of 5 nm resolution (or better) at 1.0 kV accelerating voltage for the measurement of nominal 0.25-0.35 micrometer semiconductor critical dimensions. Testing and proving that the instrument is performing at this level on a day-by-day basis is an industry need and concern which has been the object of a study at NIST and the fundamentals and results are discussed in this paper.In scanning electron microscopy, two of the most important instrument parameters are the size and shape of the primary electron beam and any image taken in a scanning electron microscope is the result of the sample and electron probe interaction. The low frequency changes in the video signal, collected from the sample, contains information about the larger features and the high frequency changes carry information of finer details. The sharper the image, the larger the number of high frequency components making up that image. Fast Fourier Transform (FFT) analysis of an SEM image can be employed to provide qualitiative and ultimately quantitative information regarding the SEM image quality.

Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

1992 ◽  
Vol 1 (4) ◽  
pp. 52-55 ◽  
Author(s):  
Gail L. MacLean ◽  
Andrew Stuart ◽  
Robert Stenstrom
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Low Frequency ◽  
Test System ◽  
Output Frequency ◽  
Frequency Effects ◽  
Adult Men ◽  
Frequency Responses ◽  
Significant Difference ◽  
Sound Pressure Levels

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

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