Design of mechanical band-pass filters with large frequency bands for energy scavenging

Mechatronics ◽  
2006 ◽  
Vol 16 (9) ◽  
pp. 523-531 ◽  
Author(s):  
S.M. Shahruz
Keyword(s):  
Energy Scavenging ◽  
Frequency Bands ◽  
Band Pass ◽  
Large Frequency

scholarly journals Compact design of diplexer for base stations operating within frequency bands 2.3–2.4/2.49–2.69 GHz

2019 ◽  
Vol 30 ◽  
pp. 06002
Author(s):  
Konstantin Kobrin ◽  
Vyacheslav Rudakov ◽  
Mikhail Manuilov
Keyword(s):  
Reflection Coefficient ◽  
Insertion Loss ◽  
Wide Band ◽  
Base Station ◽  
Base Stations ◽  
Frequency Bands ◽  
Base Station Antennas ◽  
Band Pass ◽  
Compact Design ◽  
Narrow Bands

A new compact design of diplexer with high electrical performances is proposed for base station antennas operating within frequency bands 2.3–2.4/2.49–2.69 GHz. The diplexer consists of two interdigital band-pass filters and coaxial power divider. Proposed design has high potential from view poin of implementation of wide-band as well as medium and narrow bands filters. The fabricated diplexer shows the following measured characteristics: reflection coefficient is -18 dB within passbands, insertion loss is -0.28 dB, isolation of ports is -30 dB. Diplexer has the relatively simple easy to manufacture design and compact dimensions, so it may be directly integrated into the base station antennas.

Simulation of Cortex Visual Cells for Texture Segmentation: Foveal and Parafoveal Projections

Perception ◽  
1996 ◽  
Vol 25 (1_suppl) ◽  
pp. 120-120
Author(s):  
P M Palagi ◽  
A Guérin-Dugué
Keyword(s):  
Recognition Rate ◽  
Cortical Cell ◽  
Spatial Vision ◽  
Texture Segmentation ◽  
Cortical Cells ◽  
Frequency Bands ◽  
Visual Cells ◽  
Neurophysiological Data ◽  
Band Pass ◽  
Visual Cortical

The objective of this work is to simulate visual cortical cells, their sensitivities to frequencies and orientations, and their part in texture segmentation. The simulation of these cells is realised through band-pass, oriented filters (Gabor filters), and multiresolution image decomposition. By this means, the filter sensitivities represent cell sensitivities to preferred orientations according to their frequency and orientation bandwidths, and multiresolution represents the different band frequencies. For texture analysis and segmentation, overlaying of band-pass filters is necessary to completely cover the Fourier domain. A continuous sensitivity to frequency and orientation is achieved by the filters overlapping and consequently by their interpolation. We used here four octave frequency bands from 1 to 16 cycles deg−1 and six orientations per band. The results obtained for texture segmentation with these parameters are very promising (up to 97% recognition rate) [Guérin-Dugué and Palagi, 1994 Neural Processing Letters1(1) 25 – 29]. The images analysed cover a multitude of different domains such as psychophysical tests and natural textures of different roughness. In order to create a cortical cell representation closer to neurophysiological data, and to improve texture segmentation results, we represent cell sensitivities by their foveal and parafoveal projections [R L DeValois, K K DeValois, 1988 Spatial Vision (Oxford: Oxford Science Publications)]. Cells receiving projections from the foveal zone are modeled by five octave frequency bands (from 0.5 to 16 cycles deg−1) and six orientations. Cells receiving projections from the parafoveal zone have the same sensitivities but are modeled by four octave frequency bands (from 0.5 to 8 cycles deg−1). By using these two different resolutions, preliminary tests have shown the capability of detecting textured regions by the parafoveal projection and localisation of boundaries by the foveal projection.

Large frequency bands viscoelastic properties of honey

2008 ◽  
Vol 153 (1) ◽  
pp. 46-52 ◽  
Author(s):  
J. Gasparoux ◽  
D. Laux ◽  
J.Y. Ferrandis ◽  
J. Attal ◽  
Philippe Tordjeman
Keyword(s):  
Viscoelastic Properties ◽  
Frequency Bands ◽  
Large Frequency

scholarly journals Quad-Band Rectenna for Ambient Radio Frequency (RF) Energy Harvesting

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7838
Author(s):  
Sunanda Roy ◽  
Jun Jiat Tiang ◽  
Mardeni Bin Roslee ◽  
Md Tanvir Ahmed ◽  
Abbas Z. Kouzani ◽  
...  
Keyword(s):  
Power Density ◽  
Urban Areas ◽  
High Efficiency ◽  
Wireless Local Area Network ◽  
Local Area Network ◽  
Local Area ◽  
Energy Scavenging ◽  
Area Network ◽  
Rf Power ◽  
Frequency Bands

RF power is broadly available in both urban and semi-urban areas and thus exhibits as a promising candidate for ambient energy scavenging sources. In this research, a high-efficiency quad-band rectenna is designed for ambient RF wireless energy scavenging over the frequency range from 0.8 to 2.5 GHz. Firstly, the detailed characteristics (i.e., available frequency bands and associated power density levels) of the ambient RF power are studied and analyzed. The data (i.e., RF survey results) are then applied to aid the design of a new quad-band RF harvester. A newly designed impedance matching network (IMN) with an additional L-network in a third-branch of dual-port rectifier circuit is familiarized to increase the performance and RF-to-DC conversion efficiency of the harvester with comparatively very low input RF power density levels. A dual-polarized multi-frequency bow-tie antenna is designed, which has a wide bandwidth (BW) and is miniature in size. The dual cross planer structure internal triangular shape and co-axial feeding are used to decrease the size and enhance the antenna performance. Consequently, the suggested RF harvester is designed to cover all available frequency bands, including part of most mobile phone and wireless local area network (WLAN) bands in Malaysia, while the optimum resistance value for maximum dc rectification efficiency (up to 48%) is from 1 to 10 kΩ. The measurement result in the ambient environment (i.e., both indoor and outdoor) depicts that the new harvester is able to harvest dc voltage of 124.3 and 191.0 mV, respectively, which can be used for low power sensors and wireless applications.

A frequency-approximated approach to Kirchhoff migration

Geophysics ◽  
2010 ◽  
Vol 75 (6) ◽  
pp. S211-S218 ◽  
Author(s):  
Mark E. Vardy ◽  
Timothy J. Henstock
Keyword(s):  
Time Domain ◽  
Narrow Band ◽  
Frequency Bands ◽  
Kirchhoff Migration ◽  
Frequency Decomposition ◽  
Band Pass ◽  
Band Limited ◽  
The Time Domain ◽  
Ultimate Control ◽  
Kirchhoff Integral

The integral solution of the wave equation has long been one of the most popular methods for imaging (Kirchhoff migration) and inverting (Kirchhoff inversion) seismic data. For efficiency, this process is commonly formulated as a time-domain operation on each trace, applying antialiasing through high-cut filtering of the operator or pre-/postmigration dip filtering. Migration in the time domain, however, does not allow for velocity dispersion; standard antialiasing methods assume a flat reflector and tend to overfilter the data. We have recast the Kirchhoff integral in the frequency domain, enabling robust antialias filtering through appropriate dip limiting of each frequency and implicit accommodation of true dispersion. Full frequency decomposition of the input seismogram can be approximated by band-pass filtering (or correlation with band-limited source sweeps for Chirp/Vibroseisdata) into a few narrow-band traces that cumulatively retain the full source bandwidth. From prior knowledge of the source waveform, we have defined suitable bandwidths to describe broadband (3.0 octaves) data using just six frequency bands. Kirchhoff migration of these narrow-band traces using coefficients determined at their central frequencies significantly improves the preservation of higher frequencies and cancellation of steeply dipping aliased energy over traditional time-domain antialiasing methods. If, however, two bands per octave cease to be a robust approach, our frequency-approximated approach provides the processor with ultimate control over the frequency decimation, balancing increased resolution afforded by more bands against computing cost, whereas the number of frequency bands is few enough to permit detailed control over frequency-dependent antialias filtering parameters.

scholarly journals RESULTS OF MODELING, DESIGNING AND DEVELOPMENT OF BAND-PASS ELECTRIC FILTER WITH CROSS-LINKS IN WIDE RANGE OF ULTRA HIGH FREQUENCY BANDS

2020 ◽  
pp. 7-13
Author(s):  
T.M. NARYTNYK ◽  
Keyword(s):  
Reflection Coefficient ◽  
Frequency Response ◽  
Pass Band ◽  
Band Frequency ◽  
High Slope ◽  
Frequency Bands ◽  
Wide Range ◽  
Radio Technology ◽  
Cross Links ◽  
Band Pass

The provided analysis shows the need to ensure non-interference operation of radio electronic facilities (REFs) by eliminating the incompatible radio technologies in the adjacent frequency bands or by minimizing interference as far as possible. A presented example based on the cellular communication systems suggests that one of the factors influencing the size of a guard interval is the need to ‘filter-out’ nearby radio technologies operating in opposite directions of transmission. In such instances, filters shall be used to avoid interference. Filters will allow, in the first place, to create necessary attenuation in the reception band of BS of nearby radio technology to suppress out- of-band and spurious emissions, furnishing by BS own transmitter; and in the second place, to create attenuation in the transmission band of nearby radio technology in order to reduce signals coming from BS transmitters of nearby radio technology at the input of own BS receiver. Additional high slope AFR filters may be required for both the BS transmitters and BS receivers in some frequency ranges in Ukraine. There is one more precondition for usage of high slope AFR filters having the ability to suppress main emission of transmitters by values of 30-40 dB as follows: appropriate radio frequency control and regulatory authorities are required to apply the measuring equipment within dynamic range of 80 dB. The simplified 3D filter models on 9 coaxial resonators with high Q factor which are described in the article are prepared with the help of AWR Microwave office and CST Studio Suite software tools. The simulation of AFR and frequency response for such parameter as filter reflection coefficient is also described in the article. The results of design and research concerning band-pass electric filters that have been obtained on the basis of application of the low-frequency filter prototype method are presented in the article. Prototype models of band-pass electric filters with cross-links in wide range of UHF bands (820–843 MHz and 890–915 MHz, 1920–1980 MHz and 2510–2570 MHz) are designed and produced. As a result of measurements of AFR and frequency response for the filter reflection coefficient, the attenuation within the pass-band frequency range of these filters equals to 1.5–2.0 dB; the attenuation of input signals referring to out-of-band emissions equals to 30–75 dB; the filter reflection coefficient is within minus 13 dB.

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