Second Iteration of Slotted Fractal Log Periodic Dipole Antenna for UHF Digital TV Band Application

2021 ◽  
Vol 20 (3) ◽  
pp. 48-52
Author(s):  
Muhammad Hafeez Rosmin ◽  
Mohamad Kamal A Rahim ◽  
Nur Syahirah Yaziz ◽  
Muhammad Naeem Iqbal ◽  
Osman Ayop ◽  
...  
Keyword(s):  
Reflection Coefficient ◽  
Radiation Pattern ◽  
High Frequency ◽  
Dipole Antenna ◽  
Digital Tv ◽  
Wet Etching ◽  
Tangent Loss ◽  
Frequency Range ◽  
Etching Technique ◽  
Good Agreement

This paper discusses the simulations and measurements of the antenna with and without slot implementation in terms of reflection coefficient (S11) and radiation pattern. The slot implementation on each of the radiating elements on the 2nd iteration log periodic fractal Koch antenna (LPFKA) was described in this paper. This method is utilised to reduce the antenna's size while also preventing the lower designated frequencies from shifting to the higher band as the iteration increases. The antenna is designed to test and observe performance in the Ultra High Frequency (UHF) band, which ranges from 0.5 GHz to 3.0 GHz. Computer Simulation Technology (CST) software is used to design and model the antenna, which was then built using the wet etching technique. The antenna's substrate is made of FR-4 laminated board with a dielectric constant of 4.6, tangent loss of 0.019, and a thickness of 1.6mm. The results demonstrate good agreement, with a steady radiation pattern over the operational bandwidth and a reflection coefficient of less than -10 dB for the frequency range of interest. The antenna is being tested with Digital TV decoder and the result is observed towards the picture of the Digital TV.

scholarly journals The Improvement of first Iteration Log Periodic Fractal Koch Antenna with Slot Implementation

2018 ◽  
Vol 8 (4) ◽  
pp. 2564
Author(s):  
N. S. M. Yaziz ◽  
M. K. A. Rahim ◽  
F. Zubir ◽  
N. S. Nadzir ◽  
R. Dewan ◽  
...  
Keyword(s):  
Reflection Coefficient ◽  
Radiation Pattern ◽  
Digital Television ◽  
Frequency Range ◽  
Operating Bandwidth ◽  
Good Agreement

<span>In this paper, a slotted is introduced at each of the radiating elements on the 1<sup>st</sup> iteration log periodic fractal Koch antenna (LPFKA). The antenna is designed to testify the appropriate performance at UHF Digital television which operates from 4.0 GHz to 1.0 GHz. The dimension of the conventional 0<sup>th</sup> iteration LPKFA is successfully reduced by 17% with the implementation of slotted. The results show a good agreement with a stable radiation pattern across the operating bandwidth, stable gain more than 5 dBi and reflection coefficient of below -10 dB over the desired frequency range.</span>

Hypersonic Velocity, Absorption and Relaxation in Molten CSNO3

1977 ◽  
Vol 32 (1) ◽  
pp. 57-60 ◽  
Author(s):  
H. E. Gunilla Knape ◽  
Lena M. Torell
Keyword(s):  
Relaxation Time ◽  
High Frequency ◽  
Viscosity Coefficient ◽  
Sound Waves ◽  
Frequency Range ◽  
Ultrasonic Velocities ◽  
Hypersonic Velocity ◽  
Frequency Shifts ◽  
Bulk Viscosity Coefficient ◽  
Good Agreement

Abstract Brillouin spectra of molten CSNO3 were investigated for scattering angles between 40 and 140° and in a temperature interval of 420-520 °C. An Ar+ singlemode laser was used for excitation and the total instrumental width was ~265 MHz. The measured frequency shifts and linewidths of the Brillouin components were used to determine velocities and attenuations of thermal sound waves in the frequency range 2.3-7.0 GHz. A dispersion of 4-5% was found between the present hyper­ sonic velocities and reported ultrasonic velocities. A considerable decrease in attenuation with frequency was observed in the investigated frequency range, with the value at high frequency ap­ proaching the classical attenuation. The results are in good agreement with Mountain's theory of a single relaxation time. The relaxation time of the bulk viscosity coefficient was calculated to 1.2×10-10S.

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.

scholarly journals Design and Development of a Wideband Planar Yagi Antenna Using Tightly Coupled Directive Element

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 975
Author(s):  
Muhammad A. Ashraf ◽  
Khalid Jamil ◽  
Ahmed Telba ◽  
Mohammed A. Alzabidi ◽  
Abdel Razik Sebak
Keyword(s):  
Reflection Coefficient ◽  
Wireless Communication ◽  
Radiation Pattern ◽  
Excellent Agreement ◽  
Frequency Range ◽  
Fractional Bandwidth ◽  
Yagi Antenna ◽  
Tightly Coupled ◽  
Simulation Results ◽  
Novel Concept

In this paper, a novel concept on the design of a broadband printed Yagi antenna for S-band wireless communication applications is presented. The proposed antenna exhibits a wide bandwidth (more than 48% fractional bandwidth) operating in the frequency range 2.6 GHz–4.3 GHz. This is achieved by employing an elliptically shaped coupled-directive element, which is wider compared with other elements. Compared with the conventional printed Yagi design, the tightly coupled directive element is placed very close (0.019λ to 0.0299λ) to the microstrip-fed dipole arms. The gain performance is enhanced by placing four additional elliptically shaped directive elements towards the electromagnetic field’s direction of propagation. The overall size of the proposed antenna is 60 mm × 140 mm × 1.6 mm. The proposed antenna is fabricated and its characteristics, such as reflection coefficient, radiation pattern, and gain, are compared with simulation results. Excellent agreement between measured and simulation results is observed.

scholarly journals Low-Profile Spidron Fractal Dipole Antenna with a Ferrite-Loaded Artificial Magnetic Conductor for Manpack Applications

2020 ◽  
Vol 10 (24) ◽  
pp. 8843
Author(s):  
Oh Heon Kwon ◽  
Keum Cheol Hwang
Keyword(s):  
High Frequency ◽  
Dipole Antenna ◽  
Magnetic Conductor ◽  
Very High Frequency ◽  
Artificial Magnetic Conductor ◽  
Received Power ◽  
Low Profile ◽  
Profile Characteristics ◽  
Very High ◽  
Good Agreement

In this paper, a Spidron fractal dipole antenna with a ferrite-loaded artificial magnetic conductor (AMC) is presented. By applying ferrite composed of nickel–zinc with a high permeability value, a compact AMC that operates in the broadband frequency range within the high-frequency/very-high-frequency/ultra-high-frequency (HF/VHF/UHF) bands was designed. A Spidron fractal-shaped dipole antenna with a quasi-self-complementary structure was designed and combined with a miniaturized ferrite-loaded AMC. This allowed the designed AMC-integrated dipole antenna to operate in a wide frequency band, covering the HF/VHF/UHF bands, with low-profile characteristics. A prototype of the proposed Spidron fractal dipole antenna with the AMC was manufactured and measured and found to meet low VSWR (voltage standing wave radios) specifications of <3.5 within the 20–500 MHz bandwidth range. The simulated and measured results are in good agreement. The size of the Spidron fractal dipole antenna with the AMC is 0.03×0.026×0.001λ3 relative to the wavelength of the lowest operating frequency. The received power of the Spidron fractal dipole antenna with the AMC was also measured when it was applied to relatively small applications, such as a manpack in this case.

Approaches to Predicting the Vertical Transmissibility of a Suspension Seat With a Seated Subject

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Jun Wu ◽  
Meihuan Wang ◽  
Yi Qiu
Keyword(s):  
High Frequency ◽  
Dynamic Stiffness ◽  
The Other ◽  
Human Model ◽  
Apparent Mass ◽  
Frequency Range ◽  
Air Suspension ◽  
In Series ◽  
Inert Mass ◽  
Good Agreement

Abstract In this paper, four methods were put forward to predict the transmissibility of an air suspension seat with a seated subject. For characterizing the dynamics of the suspension seat, two of the methods were based on developing a model of the air suspension seat and calibrating the parameters using the transmissibilities of the suspension and complete seat respectively with an inert mass from the experiment. The other two methods substituted the detailed modeling of the seat by two dynamic stiffness connecting in series calculated from two same transmissibilities measured in the experiment. For characterizing the biodynamics of the human body, two of the methods took advantage of the normalized apparent mass from published papers to take the place of the human model, while the other two methods made use of one measured seat transmissibility with a subject to deduce the apparent masses of all the subjects. Good agreement was illustrated between the experiment and model prediction for all the four methods. In addition, it also exhibited that a large discrepancy can be resulted in, especially in the high-frequency range, if the seat model was substituted by one integrated dynamic stiffness.

MULTIBAND CPW-FED SLOT ANTENNA FOR WLAN/WIMAX APPLICATIONS

2015 ◽  
Vol 77 (10) ◽  
Author(s):  
Igbafe Orikumhi ◽  
Mohamad Rijal Hamid ◽  
Ali Nyangwarimam Obadiah
Keyword(s):  
Radiation Pattern ◽  
Return Loss ◽  
Coplanar Waveguide ◽  
Ground Plane ◽  
Slot Antenna ◽  
Frequency Range ◽  
Resonant Frequencies ◽  
Good Agreement

A square slot antenna fed by a coplanar waveguide (CPW) is presented in this paper. The design consist of two pairs of “F” shaped planar strips placed within a square slotted ground. The strips are used to excite multiple resonant frequencies, the strips are connected to the ground plane by means of ideal switches. The proposed antenna has achieved multiple resonant frequencies of 2.4/5.2/5.8 GHz for WLAN and 3.5/5.5 for WiMAX applications. The measured results shows a good agreement with the simulated results in terms of return loss, radiation pattern and gain. The proposed antenna is designed for the frequency range of 2 GHz to 7 GHz which makes it suitable for Bluetooth, WLAN and WiMAX applications. 

Shielded open-circuited probe for in-situ measurements of soil permittivity in Very high frequency (VHF) and Ultra high frequency (UHF) bands

2021 ◽  
pp. 014233122110377
Author(s):  
Konstantin Muzalevskiy ◽  
Andrey Karavaysky
Keyword(s):  
Reflection Coefficient ◽  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
High Frequency ◽  
Mean Square ◽  
Frequency Range ◽  
Frequency Spectra ◽  
Determination Coefficient ◽  
Error Determination

In this paper, the shielded open-circuited probe operating in the wide frequency range from 75MHz to 2GHz is proposed. The probe is made of an SubMiniature version A (SMA) flange connector. The central rod of the SMA connector emerges from a coaxial transition in the flange and shielded by four rods. The robe design allows us to calculate of the probe reflection coefficient S11 used simple analytical transmission line model (TEM wave mode), the parameters of which were calibrated on a set of substances with a known frequency spectrum of permittivity. The refractive index (RI) and normalized attenuation coefficient (NAC) retrieval technique is based on solving the inverse problem of minimizing the residual norm between measured and calculated frequency spectra of reflection coefficient S11. After calibration, the root-mean-square error (determination coefficient) between the measured and calculated module and phase of the reflection coefficient S11 for the sets of calibration media air, distilled water, butanol, pure ice, water solution with NaCl of salinity of 8.9% do not exceed 0.26dB (0.995) and 0.03 rad (0.999), respectively, in the frequency range from 75MHz to 2GHz. The root-mean-square error (determination coefficient) between the measured RI and NAC spectra for four soil cover samples (variation of the clay fraction from 10.5 g/g to 47.6 g/g) using the proposed probe and a precision coaxial cell not exceeds 0.109 (0.993) and 0.057 (0.986), respectively, in the frequency range from 75 MHz to 2 GHz. As a result, it is experimentally shown that RI и NAC can be measured by the proposed non-precision probe with an error comparable to the precision coaxial cell.

Elliptical Annular Slot Loaded Trapezoidal Dipole Antenna for Band-Notched UWB Applications

2016 ◽  
Vol 12 (1) ◽  
pp. 23-29
Author(s):  
Sarthak Singhal ◽  
Nand Verma ◽  
Amit Singh
Keyword(s):  
Impedance Matching ◽  
Dipole Antenna ◽  
Frequency Range ◽  
Entire Frequency Range ◽  
Antenna Structure ◽  
Annular Slot ◽  
Notched Band ◽  
Uwb Applications ◽  
Peak Gain ◽  
Good Agreement

In this paper, a semi-elliptical annular slot loaded trapezoidal dipole antenna with band-notched characteristics for UWB applications is designed. A microstrip feedline consisting of multiple feedline sections is used for improving the impedance matching. The band-notched characteristics for WLAN band are achieved by loading the trapezoidal dipole arms with semi-elliptical annular slots. The designed antenna structure has an operating range from 3.5-12.4 GHz(109%) with band-rejection in the frequency range of 5-6 GHz. Nearly omnidirectional patterns are achieved for the designed antenna structure. The designed antenna structure provided an average peak gain of 2.12 dB over the entire frequency range except in the notched band where it reduced to -2.4 dB. The experimental and simulation results are observed to be in good agreement. An improved bandwidth performance with miniaturized dimensions as compared to earlier reported antenna structures is achieved.

scholarly journals Rectangular Ring Antenna Excited by Circular Disc Monopole for WiMAX System

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Souphanna Vongsack ◽  
Chuwong Phongcharoenpanich ◽  
Sompol Kosulvit ◽  
Kazuhiko Hamamoto ◽  
Toshio Wakabayashi
Keyword(s):  
Radiation Pattern ◽  
Circular Disc ◽  
Impedance Bandwidth ◽  
Frequency Range ◽  
Compact Size ◽  
Ring Antenna ◽  
Parametric Studies ◽  
Simulation Results ◽  
Wimax System ◽  
Good Agreement

This research presents a rectangular ring antenna excited by a circular disc monopole (CDM) mounted in front of a square reflector. The proposed antenna is designed to cover a frequency range of 2.300–5.825 GHz and thereby is suitable for WiMAX applications. Multiple parametric studies were carried out using the CST Microwave Studio simulation program. A prototype antenna was fabricated and experimented. The measurements were taken and compared with the simulation results, which indicates good agreement between both results. The prototype antenna produces an impedance bandwidth (|S11|< −10 dB) that covers the WiMAX frequency range and a constant unidirectional radiation pattern (θ=0°and∅=90°). The minimum and maximum gains are 3.7 and 8.7 dBi, respectively. The proposed antenna is of compact size and has good unidirectional radiation performance. Thus, it is very suitable for a multitude of WiMAX applications.

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