Radiation of a line source mounted between two dielectric substrates

1990 ◽  
Vol 68 (12) ◽  
pp. 1486-1491 ◽  
Author(s):  
Ioanna Diamandi ◽  
Costas Mertzianidis ◽  
John N. Sahalos
Keyword(s):  
Remote Sensing ◽  
Antenna Arrays ◽  
Line Source ◽  
Finite Thickness ◽  
Dielectric Substrate ◽  
Microstrip Antennas ◽  
The Other ◽  
Bottom Surface ◽  
Radiation Characteristics ◽  
Dielectric Substrates

The radiation characteristics of a line source lying on the bottom surface of a dielectric substrate that is mounted on the top of another one are presented. The pattern is calculated for two different cases. One is for infinite thickness of the second substrate and the other is for finite thickness. Some interesting considerations useful for applications in remote sensing, microstrip antennas, and antenna arrays are made.

Far-field patterns of line sources mounted between four-dielectric substrates

1992 ◽  
Vol 70 (2-3) ◽  
pp. 173-178 ◽  
Author(s):  
Ioanna Diamandi ◽  
Costas Mertzianidis ◽  
John N. Sahalos
Keyword(s):  
Remote Sensing ◽  
Line Source ◽  
Dielectric Substrate ◽  
Microstrip Antennas ◽  
Field Pattern ◽  
Substrate Thickness ◽  
Far Field ◽  
Dielectric Substrates ◽  
Field Patterns ◽  
Far Field Pattern

The far-field pattern characteristics of line sources lying between the slabs of a four-dielectric substrate configuration are presented. The patterns are calculated for several cases of the substrate thickness as well as for several line-source locations. The considerations that are made give useful applications in remote sensing and microstrip antennas.

RADIATION FROM ELEMENTARY FLUID-MECHANICAL SOURCES IN AN UNBOUNDED ELECTRON PLASMA

1964 ◽  
Vol 42 (8) ◽  
pp. 1573-1586 ◽  
Author(s):  
S. R. Seshadri
Keyword(s):  
Line Source ◽  
Uniform Magnetic Field ◽  
Electron Plasma ◽  
The Other ◽  
Frequency Range ◽  
Entire Frequency Range ◽  
Fluid Flux ◽  
Radiation Characteristics ◽  
Transverse Waves ◽  
Infinite Extent

The radiation characteristics of a line source of fluid flux and a line source of force, embedded in a homogeneous electron plasma of infinite extent, are investigated for the case in which a uniform magnetic field is impressed externally throughout the medium in the direction of the source. It is found that there are two propagating modes which are strictly coupled longitudinal and transverse waves. However, one of the modes is predominantly transverse in the entire frequency range of propagation and the other is predominantly transverse in the lower, and predominantly longitudinal in the higher ranges of frequency of propagation. It is shown that the elementary fluid-mechanical sources considered in this paper radiate significant amounts of power only in the longitudinal-type waves.

New Analytical Model for the Dielectric Loss of Microstrip Lines on Multilayer Dielectric Substrates: Effect of Conductor-Dielectric Interphase

2006 ◽  
Vol 3 (2) ◽  
pp. 61-66
Author(s):  
Hung T. Vo ◽  
Frank G. Shi
Keyword(s):  
Dielectric Loss ◽  
Closed Form ◽  
Finite Thickness ◽  
Dielectric Substrate ◽  
Thickness Effect ◽  
Closed Form Expression ◽  
High Frequencies ◽  
Dielectric Substrates ◽  
Microstrip Lines ◽  
Multilayer Dielectric

The existing CAD formulae for dielectric loss of microstrip lines on substrate are complicated and inaccurate at high frequencies. In particular, no closed-form expression has been obtained for the dielectric loss of microstrip lines on multi-layer dielectric substrate by including the conductor-substrate interphase effect, although attempts have been made to study the finite thickness effect of the conductor and dielectric substrate. The present work represents the first attempt to obtain a closed-form CAD formula for the dielectric loss of microstrip lines on dielectric substrates by considering the effect of conductor-substrate interphase. Our simple and accurate model systematically considers the effect of the interphase between the microstrip line and substrate by using a quasi-TEM approach and is shown to be supported by the available experimental data.

A compact CPW-fed monopole antenna for multi-band application

2021 ◽  
pp. 1-7
Author(s):  
YunYan Zhou ◽  
NianShun Zhao ◽  
RenXia Ning ◽  
Jie Bao
Keyword(s):  
Mobile Communications ◽  
Radio Frequency Identification ◽  
Communication Systems ◽  
Satellite Communication ◽  
Coplanar Waveguide ◽  
Dielectric Substrate ◽  
Monopole Antenna ◽  
Radiation Characteristics ◽  
Frequency Bands ◽  
Compact Size

Abstract A compact coplanar waveguide-fed monopole antenna is presented in this paper. The proposed antenna is composed of three monopole branches. In order to achieve the miniaturization, the longest branch was bent. The antenna is printed on an FR4 dielectric substrate, having a compact size of 0.144λ0 × 0.105λ0 × 0.003λ0 at its lowest resonant frequency of 900 MHz. The multiband antenna covers five frequency bands: 820–990 MHz, 1.87–2.08 GHz, 2.37–2.93 GHz, 3.98–4.27 GHz, and 5.47–8.9 GHz, which covers the entire radio frequency identification bands (860–960 MHz, 2.4–2.48 GHz, and 5.725–5.875 GHz), Global System for Mobile Communications (GSM) bands (890–960 MHz and 1.850–1.990 GHz), WLAN bands (2.4–2.484 GHz and 5.725–5.825 GHz), WiMAX band (2.5–2.69 GHz), X-band satellite communication systems (7.25–7.75 GHz and 7.9–8.4 GHz), and sub 6 GHz in 5G mobile communication system (3.3–4.2 GHz and 4.4–5.0 GHz). Also, the antenna has good radiation characteristics in the operating band, which is nearly omnidirectional. Both the simulated and experimental results are presented and compared and a good agreement is established. The proposed antenna operates in five frequency bands with high gain and good radiation characteristics, which make it a suitable candidate in terminal devices with multiple communication standards.

scholarly journals Mapping the Unseen: Exploiting Super-Resolution for Semantic Segmentation in Low-Resolution Images

2020 ◽  
Author(s):  
Matheus B. Pereira ◽  
Jefersson Alex Dos Santos
Keyword(s):  
Remote Sensing ◽  
Pattern Recognition ◽  
Super Resolution ◽  
Remote Sensing Data ◽  
Semantic Segmentation ◽  
The Other ◽  
Aerial Imagery ◽  
Aerial Images ◽  
Remote Sensing Images ◽  
Low Resolution

High-resolution aerial images are usually not accessible or affordable. On the other hand, low-resolution remote sensing data is easily found in public open repositories. The problem is that the low-resolution representation can compromise pattern recognition algorithms, especially semantic segmentation. In this M.Sc. dissertation1 , we design two frameworks in order to evaluate the effectiveness of super-resolution in the semantic segmentation of low-resolution remote sensing images. We carried out an extensive set of experiments on different remote sensing datasets. The results show that super-resolution is effective to improve semantic segmentation performance on low-resolution aerial imagery, outperforming unsupervised interpolation and achieving semantic segmentation results comparable to highresolution data.

scholarly journals Development of Electromagnetic Band Gap Structures in the Perspective of Microstrip Antenna Design

2013 ◽  
Vol 2013 ◽  
pp. 1-22 ◽  
Author(s):  
Md. Shahidul Alam ◽  
Norbahiah Misran ◽  
Baharudin Yatim ◽  
Mohammad Tariqul Islam
Keyword(s):  
Band Gap ◽  
Antenna Arrays ◽  
Communication Systems ◽  
Performance Enhancement ◽  
Microstrip Antennas ◽  
Microwave Devices ◽  
Electromagnetic Band Gap ◽  
Wide Range ◽  
High Efficient ◽  
Gap Characteristics

Electromagnetic band gap (EBG) technology has become a significant breakthrough in the radio frequency (RF) and microwave applications due to their unique band gap characteristics at certain frequency ranges. Since 1999, the EBG structures have been investigated for improving performances of numerous RF and microwave devices utilizing the surface wave suppression and the artificial magnetic conductor (AMC) properties of these special type metamaterial. Issues such as compactness, wide bandwidth with low attenuation level, tunability, and suitability with planar circuitry all play an important role in the design of EBG structures. Remarkable efforts have been undertaken for the development of EBG structures to be compatible with a wide range of wireless communication systems. This paper provides a comprehensive review on various EBG structures such as three-, two-, and one-dimensional (3D, 2D, and 1D) EBG, mushroom and uniplanar EBG, and their successive advancement. Considering the related fabrication complexities, implementation of vialess EBG is an attractive topic for microwave engineers. For microstrip antennas, EBG structures are used in diversified ways, which of course found to be effective except in some cases. The EBG structures are also successfully utilized in antenna arrays for reducing the mutual coupling between elements of the array. Current challenges and limitations of the typical microstrip antennas and different EBG structures are discussed in details with some possible suggestions. Hopefully, this survey will guide to increasing efforts towards the development of more compact, wideband, and high-efficient uniplanar EBG structures for performance enhancement of antenna and other microwave devices.

Calculation of the impedance characteristics of a microstrip loop antenna with a metallized dielectric substrate

2021 ◽  
Author(s):  
S.A. Korshunov
Keyword(s):  
Mathematical Models ◽  
Current Density ◽  
Mathematical Problem ◽  
Current Density Distribution ◽  
Dielectric Substrate ◽  
Microstrip Antennas ◽  
Radial Component ◽  
Method Of Integral Equations ◽  
Electrodynamic Modeling ◽  
Rigorous Model

In connection with the intensive development of electronic technology, an urgent task is the development of antennas in a microstrip way, the advantages of which are small dimensions, a relatively simple manufacturing technology, and the ability to control their characteristics by using various materials and forms of radiators in their design. Currently, there are many mathematical models of microstrip antennas with vibrator radiators located on dielectric substrates, while models of microstrip antennas with other radiator shapes are presented much less often. As a rule, the calculation of the characteristics of such antennas is performed in electrodynamic modeling systems based on the use of «closed» algorithms. In this regard, there is a need to develop rigorous mathematical models of microstrip antennas with radiators of various shapes. This work is dedicated to the development of a rigorous model of a microstrip antenna with a frame radiator located on a dielectric substrate, based on the use of the method of integral equations. An integral equation is obtained for the unknown distribution function of the radial component of the current density over a frame radiator, the numerical solution of which is a correct mathematical problem. In addition, the numerical results of calculating the current density distribution, as well as the input impedance of such an antenna for various parameters of the radiator and substrate, are presented.

scholarly journals Estimating Subsurface Thermohaline Structure of the Global Ocean Using Surface Remote Sensing Observations

2019 ◽  
Vol 11 (13) ◽  
pp. 1598 ◽  
Author(s):  
Hua Su ◽  
Xin Yang ◽  
Wenfang Lu ◽  
Xiao-Hai Yan
Keyword(s):  
Remote Sensing ◽  
Root Mean Square Error ◽  
Mean Square Error ◽  
Estimation Error ◽  
Satellite Observations ◽  
The Other ◽  
Global Ocean ◽  
Gradient Boosting ◽  
Mean Square ◽  
Thermohaline Structure

Retrieving multi-temporal and large-scale thermohaline structure information of the interior of the global ocean based on surface satellite observations is important for understanding the complex and multidimensional dynamic processes within the ocean. This study proposes a new ensemble learning algorithm, extreme gradient boosting (XGBoost), for retrieving subsurface thermohaline anomalies, including the subsurface temperature anomaly (STA) and the subsurface salinity anomaly (SSA), in the upper 2000 m of the global ocean. The model combines surface satellite observations and in situ Argo data for estimation, and uses root-mean-square error (RMSE), normalized root-mean-square error (NRMSE), and R2 as accuracy evaluations. The results show that the proposed XGBoost model can easily retrieve subsurface thermohaline anomalies and outperforms the gradient boosting decision tree (GBDT) model. The XGBoost model had good performance with average R2 values of 0.69 and 0.54, and average NRMSE values of 0.035 and 0.042, for STA and SSA estimations, respectively. The thermohaline anomaly patterns presented obvious seasonal variation signals in the upper layers (the upper 500 m); however, these signals became weaker as the depth increased. The model performance fluctuated, with the best performance in October (autumn) for both STA and SSA, and the lowest accuracy occurred in January (winter) for STA and April (spring) for SSA. The STA estimation error mainly occurred in the El Niño-Southern Oscillation (ENSO) region in the upper ocean and the boundary of the ocean basins in the deeper ocean; meanwhile, the SSA estimation error presented a relatively even distribution. The wind speed anomalies, including the u and v components, contributed more to the XGBoost model for both STA and SSA estimations than the other surface parameters; however, its importance at deeper layers decreased and the contributions of the other parameters increased. This study provides an effective remote sensing technique for subsurface thermohaline estimations and further promotes long-term remote sensing reconstructions of internal ocean parameters.

scholarly journals Analytic modelling of a planar Goubau line with circular conductor

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tobias Schaich ◽  
Daniel Molnar ◽  
Anas Al Rawi ◽  
Mike Payne
Keyword(s):  
Numerical Simulations ◽  
Propagation Constant ◽  
Finite Thickness ◽  
Approximate Equation ◽  
Dielectric Substrate ◽  
Transverse Magnetic ◽  
Wave Mode ◽  
Velocity Measurements ◽  
Low Loss ◽  
Transverse Magnetic Mode

AbstractPlanar Goubau lines show promise as high frequency, low-loss waveguides on a substrate. However, to date only numerical simulations and experimental measurements have been performed. This paper analytically investigates the surface wave mode propagating along a planar Goubau line consisting of a perfectly conducting circular wire on top of a dielectric substrate of finite thickness but infinite width. An approximate equation for the propagation constant is derived and solved through numerical integration. The dependence of the propagation constant on various system parameters is calculated and the results agree well with full numerical simulations. In addition, the spatial distribution of the longitudinal electric field is reported and excellent agreement with a numerical simulation and previous studies is found. Moreover, validation against experimental phase velocity measurements is also reported. Finally, insights gained from the model are considered for a Goubau line with a rectangular conductor. The analytic model reveals that the propagating mode of a planar Goubau line is hybrid in contrast to the transverse magnetic mode of a classic Goubau line.

scholarly journals Implementation of Simultaneous Multi-Parameter Monitoring Based in LC-Type Passive Wireless Sensing with Partial Overlapping and Decoupling Coils

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5183
Author(s):  
Juan Ignacio Sancho ◽  
Noemí Perez ◽  
Joaquin De Nó ◽  
Jaizki Mendizabal
Keyword(s):  
Remote Sensing ◽  
Wireless Sensors ◽  
Mutual Coupling ◽  
The Other ◽  
Wireless Sensing ◽  
Passive Wireless Sensors ◽  
Parameter Monitoring

Inductor–capacitor (LC) passive wireless sensors are widely used for remote sensing. These devices are limited in applications where multiparameter sensing is required, because of the mutual coupling between neighboring sensors. This article presents two effective decoupling techniques for multiparameter sensing, based on partially overlapped sensors and decoupling coils, which, when combined, reduce the mutual coupling between sensors to near zero. A multiparameter LC sensor prototype with these two decoupling mechanisms has been designed, simulated, and measured. This prototype is capable of simultaneously measuring four parameters. The measurements demonstrate that the changes in capacitance in one individual sensor do not affect the measurements of the other sensors. This principle has been applied to simultaneous wear sensing using four identical wear sensors.

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