scholarly journals Narrowband-to-Narrowband Frequency Reconfiguration with Harmonic Suppression Using Fractal Dipole Antenna

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
S. A. Hamzah ◽  
M. Esa ◽  
N. N. N. A. Malik ◽  
M. K. H. Ismail
Keyword(s):  
Dipole Antenna ◽  
Single Frequency ◽  
Harmonic Suppression ◽  
Frequency Range ◽  
Low Loss ◽  
Harmonic Frequency ◽  
Radiating Element ◽  
Measurement Results ◽  
Specific Frequency ◽  
Original Size

Harmonic suppressed fractal antenna with switches named TMFDB25 is developed to select desired frequency band from 400 MHz to 3.5 GHz. The radiating element length is changed to tune the operating frequency while the stub is used to eliminate the undesired harmonic frequency. The balun circuit is reduced by 75% from the original size. The antenna is built on a low loss material. It has the ability to select a single frequency out of fifteen different bands and maintain the omnidirectional radiation pattern properties. Furthermore, the antenna is designed, built, and tested. Simulation and measurement results show that the antenna operates well at the specific frequency range. Therefore, the antenna is suitable to be used for switching frequencies in the band of TV, GSM900/1800, 3G, ISM 2.4 GHz, and above.

scholarly journals Design of Broadband Compact Canonical Triple-Sleeve Antenna Operating in UHF Band

2021 ◽  
Vol 21 (4) ◽  
pp. 291-298
Author(s):  
Chandana SaiRam ◽  
Damera Vakula ◽  
Mada Chakravarthy
Keyword(s):  
Wireless Communication ◽  
Instantaneous Frequency ◽  
Dipole Antenna ◽  
Frequency Range ◽  
Broadband Antenna ◽  
Operating Frequency Range ◽  
Half Wave ◽  
Measurement Results ◽  
Antenna Configuration ◽  
Good Agreement

In this paper, a novel compact broadband antenna at UHF frequencies is presented with canonical shapes. Hemispherical, conical and cylindrical shapes have all been considered for antenna configuration. The designed antenna provides an instantaneous frequency range from 370 to 5,000 MHz with omnidirectional characteristics. The antenna was simulated in CST Microwave Studio, fabricated and evaluated; the results are presented. The simulated and measurement results are in good agreement. The antenna has voltage standing wave ratio (VSWR) ≤ 1.9:1 in 400–570 MHz, 2,530–3,740 MHz and 4,180–4,620 MHz; it has VSWR ≤ 3:1 over the operating frequency range 370–5,000 MHz and the measured gain varies from -0.6 to 4.5 dBi over the frequency band. The concept of canonical-shaped antenna elements and the incorporation of triple sleeves resulted in a reduction of the length of the antenna by 62% compared to the length of a half-wave dipole antenna designed at the lowest frequency. The antenna can be used for trans-receiving applications in wireless communication.

Mechanical-Condition Assessment of Power Transformer Using Vibroacoustic Analysis

2012 ◽  
Vol 500 ◽  
pp. 40-44 ◽  
Author(s):  
Eugeniusz Kornatowski
Keyword(s):  
Steady State ◽  
Vibration Frequency ◽  
Power Transformer ◽  
Wide Frequency Range ◽  
Analysis Method ◽  
Frequency Range ◽  
Harmonic Frequency ◽  
Measurement Results ◽  
Relative Coefficient ◽  
Vibration Frequency Spectrum

This paper presents a method for vibroacoustic analysis of a transformer in the steady state. The standard approach to this problem has been based on analysis of the vibration frequency spectrum recorded with an accelerometer mounted on the transformer’s tank. To improve legibility of measurement results, the paper suggests the analysis method for the relative coefficient of harmonic frequency contents hnorm(f). The conducted experiment showed that high values of hnorm within a wide frequency range testify to deformation of windings and degradation of solid insulation.

scholarly journals Investigation on Symmetric and Asymmetric Broadband Low-Loss W-Band Pillbox Windows

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2060
Author(s):  
Tongbin Yang ◽  
Xiaotong Guan ◽  
Wenjie Fu ◽  
Dun Lu ◽  
Chaoyang Zhang ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Wide Band ◽  
Simulation Software ◽  
Experimental Results ◽  
Frequency Range ◽  
Low Loss ◽  
W Band ◽  
Measurement Results ◽  
Vacuum Electronic Devices ◽  
Wave Region

In order to develop wide-band low-loss windows for W-band vacuum electronic devices and easily fabricate them, symmetric and asymmetric pillbox windows are investigated and reported in this paper. A symmetric pillbox window and an asymmetric pillow-box window were designed, simulation optimized, fabricated, and tested. The initial parameters for the two pillbox windows were designed by equivalent circuit theory. Computer simulation technology (CST) three-dimensional (3D) electromagnetic simulation software was used to verify and optimize the design. Because of the uncontrollability of welding during the experiment, this article provides two solutions. One is to measure and reprocess the symmetrical pillbox window with the dielectric sheet welded to reduce the influence of welding on the measurement results; the other is an asymmetrical box window which is designed to avoid the error caused by the welding of the box window. The best experimental results for the symmetric pillbox window were |S21| close to 1 dB and reflection parameter |S11| close to 10 dB in the frequency range of 77–110 GHz. The experimental results for the asymmetric pillbox window were |S21| < 1 dB nearly in the frequency range of 76–109.5 GHz. The experimental results show that both solutions efficiently complete the design of broadband pillbox windows and would potentially be operated in the gigahertz millimeter-wave region.

Design and Characterization of an Ultra Low Loss, Dispersion-Flattened Slotted Photonic Crystal Fiber for Terahertz Application

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohammad Rakibul Islam ◽  
Md. Arif Hossain ◽  
Syed Iftekhar Ali ◽  
Jakeya Sultana ◽  
Md. Saiful Islam
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystal Fiber ◽  
Single Mode ◽  
Confinement Loss ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Low Loss ◽  
Material Loss ◽  
Crystal Fiber

AbstractA novel photonic crystal fiber (PCF) based on TOPAS, consisting only rectangular slots is presented and analyzed in this paper. The PCF promises not only an extremely low effective material loss (EML) but also a flattened dispersion over a broad frequency range. The modal characteristics of the proposed fiber have been thoroughly investigated using finite element method. The fiber confirms a low EML of 0.009 to 0.01 cm−1 in the frequency range of 0.77–1.05 THz and a flattened dispersion of 0.22±0.01 ps/THz/cm. Besides, some other significant characteristics like birefringence, single mode operation and confinement loss have also been inspected. The simplicity of the fiber makes it easily realizable using the existing fabrication technologies. Thus it is anticipated that the new fiber has the potential to ensure polarization preserving transmission of terahertz signals and to serve as an efficient medium in the terahertz frequency range.

scholarly journals Printed dipole antenna and its arrays for wireless applications

2018 ◽  
Vol 7 (2.7) ◽  
pp. 952
Author(s):  
V Teju ◽  
P V. P. S Nikhil ◽  
A Pranusha ◽  
Ch Divya ◽  
G Bhanuprakash
Keyword(s):  
Reflection Loss ◽  
Mutual Coupling ◽  
Dipole Antenna ◽  
Wide Frequency Range ◽  
Single Element ◽  
Frequency Range ◽  
Scanning Angle ◽  
Wireless Applications ◽  
Element Array

This paper proposes single element of micro-stripe antenna having wider bandwidth and also its arrays which are implemented for wire-less applications. In contemplation of wide frequency range of operation, antenna is fed with integrated balun. The single element antenna works under frequency range of 34GHz to 46GHz where reflection loss is less than -10dB and the obtained gain is 2.1 dBi. The linear 8-element array of antenna has been implemented and to obtain low mutual coupling between the elements of antenna a rectangular stub has been implemented. By enforcing the array methodology the not only the overall gain of the antenna has increased but also results in wider scanning angle.  

scholarly journals A Novel Frequency Reconfigurable Microstrip Patch Antenna using Pin Diode

2020 ◽  
Vol 9 (5) ◽  
pp. 2013-2017
Keyword(s):  
Patch Antenna ◽  
Return Loss ◽  
Microstrip Patch Antenna ◽  
Pin Diode ◽  
Optimum Level ◽  
Frequency Range ◽  
Microstrip Patch ◽  
Single Antenna ◽  
Specific Frequency ◽  
Switching State

In recent study, in the growth of wireless technology single antenna that works with a specific frequency is becoming outdated. The antenna which is capable to work dynamically is encouraged. To make an antenna to work dynamically, modification in any of the antenna characteristics can be applied. In this proposed work, the antenna which can reconfigure its frequency is designed and analyzed. Microstrip patch antenna is most popular printed type antenna which is suitable for diverse applications. The antenna design consists of three PIN diodes which are placed in different positions on the patch. Depending upon the switching state of PIN diode the antenna can operate in different frequency ranges. The frequency range obtained ranges from 1.38 GHz to 3.24 GHz. Return loss value, VSWR obtained is of optimum level. The various gain of antenna is obtained in simulation. The analysis of the antenna is done in ANSYS HFSS software.

Wideband and Low-Loss Magneto-Electric Dipole Antenna Fed by Printed Ridge-Gap Waveguide Technology

2021 ◽  
Author(s):  
Zahra Mousavirazi ◽  
Vahid Rafiei ◽  
Mohamed Mamdouh M. Ali ◽  
Tayeb A. Denidni
Keyword(s):  
Electric Dipole ◽  
Dipole Antenna ◽  
Low Loss

scholarly journals Low-loss Cd-substituted Mg ferrites with matching impedance for high-frequency-range antennas

2020 ◽  
Author(s):  
Gongwen Gan ◽  
Dainan Zhang ◽  
Jie Li ◽  
Gang Wang ◽  
Xin Huang ◽  
...  
Keyword(s):  
High Frequency ◽  
High Frequency Range ◽  
Frequency Range ◽  
Low Loss

A novel Ka-band MMIC coupled filter with harmonic suppression

Circuit World ◽  
2020 ◽  
Vol 46 (3) ◽  
pp. 169-173
Author(s):  
Jin Guan ◽  
Min Gong ◽  
Bo Gao
Keyword(s):  
Pass Band ◽  
Wave System ◽  
Harmonic Suppression ◽  
Low Loss ◽  
Coupled Line ◽  
Ka Band ◽  
Content Type ◽  
Harmonic Frequencies ◽  
Full Wave ◽  
On Chip

Purpose A novel Ka-band compact parallel-coupled microstrip bandpass filter with harmonic suppression performance has been designed, implemented and tested on GaAs MMIC. Design/methodology/approach This proposed filter consists of modified coupled-line units with T-shaped open-stubs. Findings The proposed filter with T-shaped open-stubs is valuable in performance with low loss at fundamental frequency, suppression at harmonic frequencies and small size. The simulation is based on full-wave electromagnetic analysis and the measurement is based on chip test. It shows an insertion loss below 1.2 dB, return loss better than 20 dB in the pass band and high than 28 dB suppression at harmonic frequencies. Originality/value This Ka-band MMIC filter with harmonic suppression is attractive for the millimeter-wave system.

scholarly journals Measurements of acoustic scattering from zooplankton and oceanic microstructure using a broadband echosounder

2009 ◽  
Vol 67 (2) ◽  
pp. 379-394 ◽  
Author(s):  
Andone C. Lavery ◽  
Dezhang Chu ◽  
James N. Moum
Keyword(s):  
High Frequency ◽  
System Performance ◽  
Pulse Compression ◽  
Acoustic Scattering ◽  
Single Frequency ◽  
Frequency Range ◽  
Range Resolution ◽  
Continuous Frequency ◽  
Processing Techniques ◽  
Signal Processing Techniques

Abstract Lavery, A. C., Chu, D., and Moum, J. N. 2010. Measurements of acoustic scattering from zooplankton and oceanic microstructure using a broadband echosounder. – ICES Journal of Marine Science, 67: 379–394. In principle, measurements of high-frequency acoustic scattering from oceanic microstructure and zooplankton across a broad range of frequencies can reduce the ambiguities typically associated with the interpretation of acoustic scattering at a single frequency or a limited number of discrete narrowband frequencies. With this motivation, a high-frequency broadband scattering system has been developed for investigating zooplankton and microstructure, involving custom modifications of a commercially available system, with almost complete acoustic coverage spanning the frequency range 150–600 kHz. This frequency range spans the Rayleigh-to-geometric scattering transition for some zooplankton, as well as the diffusive roll-off in the spectrum for scattering from turbulent temperature microstructure. The system has been used to measure scattering from zooplankton and microstructure in regions of non-linear internal waves. The broadband capabilities of the system provide a continuous frequency response of the scattering over a wide frequency band, and improved range resolution and signal-to-noise ratios through pulse-compression signal-processing techniques. System specifications and calibration procedures are outlined and the system performance is assessed. The results point to the utility of high-frequency broadband scattering techniques in the detection, classification, and under certain circumstances, quantification of zooplankton and microstructure.

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