scholarly journals Tunable microstrip liquid crystals patch antennas

2021 ◽  
Vol 1198 (1) ◽  
pp. 012010
Author(s):  
N A Romanov ◽  
T A Chimytov ◽  
A V Nomoev ◽  
E Ch Khartaeva ◽  
E A Gurvitz
Keyword(s):  
Dielectric Constant ◽  
Liquid Crystals ◽  
Magnetic Nanoparticles ◽  
Phase Shift ◽  
Patch Antenna ◽  
High Frequency ◽  
Dielectric Anisotropy ◽  
Slight Variation ◽  
Patch Antennas ◽  
Frequency Range

Abstract A patch antenna based on liquid crystals for the5G GHz range was simulated. The variation of the antenna frequency range after doping magnetic nanoparticles was verified. The high-frequency patch antenna parameters are calculated considering the dependence of the reflectivity of the antenna 11 on the dielectric anisotropy, gain, directivity and phase shift. The ability to control the frequency range of the patch antenna is shown. The phase distributions were demonstrated for 5CB crystals with a slight variation in the dielectric constant tensor and crystals with magnetic permeability.

scholarly journals Dielectric Spectroscopy Analysis of Liquid Crystals Recovered from End-of-Life Liquid Crystal Displays

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2873
Author(s):  
Ana Barrera ◽  
Corinne Binet ◽  
Frédéric Dubois ◽  
Pierre-Alexandre Hébert ◽  
Philippe Supiot ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
End Of Life ◽  
Room Temperature ◽  
Liquid Crystal Displays ◽  
Dielectric Anisotropy ◽  
Frequency Range ◽  
Spectroscopy Analysis ◽  
Diamond Nanoparticles ◽  
Nematic Phases ◽  
Universal Law

In the present work, the dielectric properties of recycled liquid crystals (LCs) (non-purified, purified, and doped with diamond nanoparticles at 0.05, 0.1, and 0.2 wt%) were investigated. The studied LC mixtures were obtained from industrial recycling of end-of-life LC displays presenting mainly nematic phases. Dielectric measurements were carried out at room temperature on a frequency range from 0.1 to 106 Hz using an impedance analyzer. The amplitude of the oscillating voltage was fixed at 1 V using cells with homogeneous and homeotropic alignments. Results show that the dielectric anisotropy of all purified samples presents positive values and decreases after the addition of diamond nanoparticles to the LC mixtures. DC conductivity values were obtained by applying the universal law of dielectric response proposed by Jonscher. In addition, conductivity of the doped LC mixtures is lower than that of the undoped and non-purified LC.

scholarly journals Iterative Analysis of Dielectric Constant of Patch Antenna Substrate at UHF Band

2018 ◽  
Vol 7 (2.16) ◽  
pp. 7
Author(s):  
Amish Kumar Jha ◽  
Bharti Gupta Gupta ◽  
Preety D Swami
Keyword(s):  
Dielectric Constant ◽  
Material Properties ◽  
Patch Antenna ◽  
Dielectric Materials ◽  
Substrate Material ◽  
Frequency Range ◽  
Shape Model ◽  
Iterative Analysis ◽  
Working Frequency ◽  
Simulation Results

This paper presents an investigation of effect of substrate material properties on the performance of antenna. The simulations are tested for 30 different dielectric materials on the basic RPA antenna model as well as on the most common U shape model using CST Microwave Studio. Two designs are proposed. On the basis of simulation results it has been concluded that for the first design the best material is which has a dielectric constant of 2.7 (𝜀r = 2.7) with bandwidth improvements of around 69.33% to 88.6% as compared to the most frequently used materials at present. For the second design the best result is obtained for the material that has dielectric constant in the range 2.0 to 2.7.  For a material having dielectric constant of 2.1 (𝜀r = 2.1) bandwidth improvement of around 11.74% with respect to RT Duroid was observed. For the second design, radiations from all other materials were not available in the working frequency range of 1GHz to 6GHz.  

Gain enhancement of microstrip patch antenna using Sierpinski fractal-shaped EBG

2015 ◽  
Vol 8 (6) ◽  
pp. 915-919 ◽  
Author(s):  
Neeraj Rao ◽  
Dinesh Kumar Vishwakarma
Keyword(s):  
Patch Antenna ◽  
High Frequency ◽  
Microstrip Patch Antenna ◽  
Patch Antennas ◽  
Electromagnetic Band Gap ◽  
Gain Enhancement ◽  
Microstrip Patch Antennas ◽  
Microstrip Patch ◽  
Rectangular Patch ◽  
Frequency Components

This is the first report on novel mushroom-type electromagnetic band gap (EBG) structures, consisting of fractal periodic elements, used for enhancing the gain of microstrip patch antennas. Using CST Microwave studio the performance of rectangular patch antenna has been examined on proposed fractal EBG substrates. It is found that fractal EBGs are more effective in suppressing surface wave thus resulting in higher gain. The gain of rectangular patch has been improved from 6.88 to 10.67 dBi. The proposed fractal EBG will open new avenues for the design and development of variety of high-frequency components and devices with enhanced performance.

Low Loss LTCC Ag System for 5G Applications

2021 ◽  
Vol 2021 (HiTEC) ◽  
pp. 000105-000111
Author(s):  
Ellen Tormey ◽  
Chao Ma ◽  
John Maloney ◽  
Bradford Smith ◽  
Sid Sridharan ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
High Frequency ◽  
Lower Cost ◽  
Low Dielectric Constant ◽  
Low Latency ◽  
Frequency Range ◽  
Low Loss ◽  
Green Tape ◽  
Low Dielectric ◽  
Wireless Telecommunications

Abstract Low dielectric constant/low loss LTCC materials have drawn much attention with the emergence of 5G wireless telecommunications. LTCC offers unique properties in the millimeter wave frequency range. The low dielectric constant and dielectric loss enable low latency devices with enhanced performance. To meet the market demands of higher performance and lower cost, Ferro has developed a new M7 LTCC/Ag cofireable system suitable for antenna in 5G and other high frequency applications. M7 LTCC ceramic green tape and cofireable Ag conductors have been developed and tested. Properties of the LTCC/Ag system are included herein including high frequency dielectric properties.

scholarly journals A Passive Wireless Crack Sensor Based on Patch Antenna with Overlapping Sub-Patch

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4327 ◽  
Author(s):  
Songtao Xue ◽  
Zhuoran Yi ◽  
Liyu Xie ◽  
Guochun Wan ◽  
Tao Ding
Keyword(s):  
Patch Antenna ◽  
High Frequency ◽  
Crack Width ◽  
Patch Antennas ◽  
Cavity Model ◽  
Measuring Range ◽  
Resonant Frequencies ◽  
Frequency Shifts ◽  
Strain Transfer ◽  
High Frequency Structure Simulator

Monolithic patch antennas for deformation measurements are designed to be stressed. To avoid the issues of incomplete strain transfer ratio and insufficient bonding strength of stressed antennas, this paper presents a passive wireless crack sensor based on an unstressed patch antenna. The rectangular radiation patch of the proposed sensor is partially covered by a radiation sub-patch, and the overlapped length between them will induce the resonate frequency shift representing the crack width. First, the cavity model theory is adopted to show how the resonant frequencies of the crack sensor are related to the overlapped length between the patch antenna and the sub-patch. This phenomenon is further verified by numerical simulation using the Ansoft high-frequency structure simulator (HFSS), and results show a sensitivity of 120.24 MHz/mm on average within an effective measuring range of 1.5 mm. One prototype of proposed sensor was fabricated. The experiments validated that the resonant frequency shifts are linearly proportional to the applied crack width, and the resolution is suitable for crack width measuring.

Dielectric Properties of PMN/CB/CIIR Composites

2009 ◽  
Vol 66 ◽  
pp. 234-237 ◽  
Author(s):  
Hao Yan ◽  
Zhi Xiong Huang ◽  
Yan Bing Wang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Carbon Black ◽  
Lead Titanate ◽  
High Frequency ◽  
Dielectric Constants ◽  
Frequency Range ◽  
Magnesium Niobate ◽  
Chlorobutyl Rubber

The Magnesium Niobate-Lead Titanate (PMN) / conductive carbon black (CB)/ chlorobutyl rubber(CIIR) composites were prepared by blending-vulcanization method, and the dielectric properties were studied. The results showed that the dielectric constant and dielectric loss of composites increased nonlinearly when increasing the content of PMN or CB. From the curve of dielectric constant vs frequency, it is obtained that in the frequency range from 103 to 106 Hz, the dielectric constant of PMN/CB/CIIR composites decreased with the frequency increasing and the dielectric constants are more stable under high frequency.

THE EFFECTS OF STRUCTURAL-INDUCED DEFORMATION ON THE RESONANCE OF PATCH ANTENNAS

2021 ◽  
Author(s):  
KELVIN NICHOLSON ◽  
JOHN WANG ◽  
ROWAN HEALEY ◽  
TAYLOR LYNCH ◽  
JOEL PATNIOTIS ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Patch Antenna ◽  
High Frequency ◽  
Aerodynamic Performance ◽  
Patch Antennas ◽  
Direct Integration ◽  
Structural Efficiency ◽  
High Frequency Structure Simulator ◽  
Resonant Behavior ◽  
Structural Loading

Conformal Loadbearing Antenna Structures (CLAS) take advantage of a combination of structural and electromagnetic functions. CLAS have been developed as an advanced replacement for conventional antennas (such as blades, wires and dishes) to improve the structural efficiency, as well as the electromagnetic and aerodynamic performance of a platform. The CLAS concept permits the direct integration of microwave radiating elements in the structural skin of a platform. Therefore, the antenna will be subjected to structural loading and will deform accordingly. The effects of these structural-induced deformations on the resonant frequency of the antenna will be reported in this paper. This paper will investigate the performance of a carbon veil patch antenna when it is subject to static in-plane. The work presented will include the effects of in-plane loading on the resonant behavior of the patch antenna when the carbon veil is fully bonded and when it is disbonded by the parent structure. This paper will also discuss the effects of substrate delamination on the RF response of the patch antenna. The RF characteristics of the antenna will be modelled using ANSYS High Frequency Structure Simulator (HFSS).

Dielectric Studies of Binary Mixtures of 1-Propanol and Fluorobenzene

2013 ◽  
Vol 209 ◽  
pp. 203-206 ◽  
Author(s):  
Ashvin N. Prajapati ◽  
Vipinchandra A. Rana ◽  
A.D. Vyas ◽  
S.P. Bhatanagar ◽  
D.H. Gadani
Keyword(s):  
Dielectric Constant ◽  
Binary Mixtures ◽  
Complex Permittivity ◽  
High Frequency ◽  
Low Frequency ◽  
Microwave Frequency ◽  
Static Dielectric Constant ◽  
Frequency Range ◽  
Optical Dielectric Constant ◽  
Optical Dielectric

Complex permittivity spectra of 1-Propanol (1-PrOH), Fluorobenzene (FB) and their binary mixtures are obtained in radio and microwave frequency range using Vector network analyzer (VNA) operating in the frequency range 0.3 MHz to 3.0 GHz and standard microwave benches operated at 9.1 GHz and 19.61 GHz. Static dielectric constant (ε0) and high frequency limiting dielectric constant (ε∞1) for binary mixtures of 1-PrOH and FB are obtained by extrapolating the complex permittivity data towards low frequency side and high frequency side on complex plane plots. Optical dielectric constant (ε∞ = n2) for binary mixtures are measured using Abbe's refractometer. Excess static dielectric constant (ε0)E, Kirkwood correlation parameters (g, geff and gf) and Bruggeman factor (fB) are determined from the values of static dielectric constant (ε0) and optical dielectric constant (ε∞). These parameters have been discussed to explore the molecular interaction between the molecular species.

Thermally stabilized bismaleimide–triazine resin composites for 10-GHz level high-frequency application

2017 ◽  
Vol 30 (7) ◽  
pp. 833-839 ◽  
Author(s):  
Jie Yang ◽  
Xin Mao ◽  
Lirong Du ◽  
Bo Wu ◽  
Fangfang Zhang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Frequency ◽  
Decomposition Temperature ◽  
Resin Composites ◽  
Frequency Range ◽  
Initial Decomposition Temperature ◽  
Curing Reaction ◽  
High Frequency Application ◽  
The Stability

A hybrid cured resin with excellent dielectric and thermal properties was prepared with bismaleimide–triazine (BT) resin modified with 2,2′-diallylbisphenol A (DBA). The thermal and dielectric properties of the resin were investigated, and the effect of DBA concentration on the curing reaction was determined. Results indicated that DBA significantly influenced the curing reaction and the properties of the cured product. The modified BT resins exhibited outstanding thermal stability (initial decomposition temperature was over 400°C), although the stability was slightly lower than that of pure BT resins. The dielectric constant and dielectric loss of the cured resin decreased when DBA was introduced into the BT resins. Moreover, the fabricated resins showed dielectric constant of 2.91–3.07 and dielectric loss lower than 0.0057 under the testing high-frequency range of 1 GHz to 15 GHz. Overall, the BT resins modified by DBA display great potential to be applied in high frequency field.

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