A SIW Horn Antenna without Broad Wall Loaded with Trapezoidal Air Slot

2020 ◽  
Vol 35 (9) ◽  
pp. 1047-1052
Author(s):  
Mingxi Zhang ◽  
Wei Li ◽  
Shaobin Liu ◽  
Xiaochun Liu ◽  
Chen Wu ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Surface Waves ◽  
Free Space ◽  
Impedance Matching ◽  
Horn Antenna ◽  
Dielectric Substrate ◽  
Actual Measurement ◽  
Relative Bandwidth ◽  
Measurement Results ◽  
Wide Wall

In this paper, a SIW horn antenna without broad wall loaded with trapezoidal air slot is proposed, processed, and tested. Based on the SIW horn antenna, this antenna strips off the wide wall at the horn diameter, introduces surface waves on the surface of the dielectric substrate, and improves the impedance matching between the antenna and free space. Further, trapezoidal air slots are loaded on the exposed dielectric substrate, gradually changes the dielectric constant of the dielectric substrate, so that the dielectric constant of the dielectric substrate can get closer to which of air, and the working bandwidth can be further expanded. The actual measurement results show that the working bandwidth of the antenna is 15.2-38GHz, the relative bandwidth reaches to 85.7%, and the maximum gain in the band is 9.1dBi.

scholarly journals A Compact Wideband Dielectric Loaded H-plane Sectoral Ridged SIW Horn Antenna

2020 ◽  
Vol 9 (2) ◽  
pp. 1-6
Author(s):  
M. Reshadatmand ◽  
H. R. Hassani ◽  
S. Mohammad Ali Nezhad
Keyword(s):  
Reflection Coefficient ◽  
Free Space ◽  
Horn Antenna ◽  
Dielectric Substrate ◽  
Substrate Integrated Waveguide ◽  
Ridge Structure ◽  
Software Packages

In this paper a compact and wideband ridged substrate integrated waveguide (RSIW) horn antenna is proposed. Unlike the previous works, the ridge structure in the proposed antenna is tapered only along the width allowing the antenna to be designed on just two-layer dielectric substrate. The tapered ridge is created by simple, different diameter size vias just in one layer. The antenna designed has dimension of 14 × 33 × 3 mm3 (1.4λo × 3.3λo × 0.3λo, where λo is the free space wavelength at 30 GHz) and a has a bandwidth of 41.32% covering 24 - 36.5 GHz with the reflection coefficient, S11, under -10 dB. The antenna is simulated through two software packages CST and HFSS and results are compared.

A MoS2-based broadband and multiband metamaterial absorber in the visible band

2020 ◽  
Vol 34 (34) ◽  
pp. 2050397
Author(s):  
Shitong Song ◽  
Fanyi Liu ◽  
Limei Qi ◽  
Zhao Zhang ◽  
Haodong Wang ◽  
...  
Keyword(s):  
Physical Mechanism ◽  
Impedance Matching ◽  
Dielectric Substrate ◽  
Metamaterial Absorber ◽  
Matching Theory ◽  
Broadband Absorber ◽  
Broadband Absorption ◽  
Visible Band ◽  
Relative Bandwidth ◽  
New Perspective

A broadband MoS2-based absorber composed of Ag rod/MoS2/dielectric/Ag is proposed in the visible band. The relative bandwidth is 65% for the absorption above 80%. The absorber also has the properties of polarization-independence and wide-angle absorption. Impedance matching theory is used to analyze the physical mechanism of the broadband absorption. By investigating the absorption property of each part of the absorber, it is found that the absorption is enhanced by introducing the two-dimensional material MoS2. The broadband absorber can be changed to be multiband absorber by changing the thickness of dielectric substrate. This structure provides a new perspective to enhance absorption in the visible band and has promising applications in solar cells.

scholarly journals A Polyimide-Based Flexible Monopole Antenna Fed by a Coplanar Waveguide

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 334
Author(s):  
Dingyong Cang ◽  
Zhiliang Wang ◽  
Huiwen Qu
Keyword(s):  
Ion Exchange ◽  
Resonance Frequency ◽  
Coplanar Waveguide ◽  
Dielectric Substrate ◽  
Reduction Reaction ◽  
Monopole Antenna ◽  
Prepared Film ◽  
Relative Bandwidth ◽  
Measurement Results

A 2.4 GHz flexible monopole antenna fed by a coplanar waveguide (CPW) was presented on polyimide (PI) as the dielectric substrate, which was fabricated by in situ self-metallization. The technology does not depend on expensive equipment or complex experimental environments, including hydrolysis, ion exchange, and reduction reaction. The measurement results show that the resonance frequency of the proposed antenna is 2.28 GHz, the bandwidth is 2.06–2.74 GHz, and the relative bandwidth is 28.33% under the flat state. The bending and folding test was also carried out. Whether it was flat, bent, or folded, the measured results met the requirements of the antenna. A fatigue test was carried out to illustrate that the prepared film has high mechanical flexibility, which expands the application field of antenna.

scholarly journals Design of Ultrawide Bandwidth Electromagnetic Wave Absorbers with Square Patch Frequency Selective Surfaces with Different Geometries

2020 ◽  
Vol 58 (5) ◽  
pp. 326-333
Author(s):  
Tian Liu ◽  
Sung-Soo Kim
Keyword(s):  
Electromagnetic Wave ◽  
Free Space ◽  
Impedance Matching ◽  
Test Sample ◽  
Dielectric Substrate ◽  
Frequency Selective Surfaces ◽  
Total Thickness ◽  
Wide Bandwidth ◽  
Wire Conductor ◽  
Frequency Selective

A reliable and efficient numerical method is presented for the design of broadband absorbers, fabricated by layering two square patch-frequency selective surfaces (SP-FSS) with different geometries on a grounded dielectric substrate. The circuit parameters of the inductance and capacitance of the SP-FSS were retrieved using the strip wire conductor model. Due to the high capacitance and low inductance of the SPFSS, a nearly constant resonance frequency (<i>f</i><sub>0</sub> = 37 GHz) is observed, irrespective of patch size at a given unit cell periodicity of 7.5 mm. For the SP-FSS, the circuit is capacitive below <i>f</i><sub>0</sub> and inductive above <i>f</i><sub>0</sub>. For a grounded substrate with a quarter wavelength thickness, however, the input impedance is inductive below <i>f</i><sub>0</sub>, resulting in impedance matching over a wide frequency range, with the controlled FSS resistance matched to the free-space impedance. The double-layer absorber was designed by optimizing the surface resistance and layer thickness of two SP-FSSs with different geometries, and demonstrated a 10 dB absorption bandwidth of 6.1−41.4 GHz with a total thickness of 5 mm, which is equal to the theoretical limit. A test sample was prepared by screen printing method, and the free space measurement demonstrated a wide-bandwidth absorption result (4.7−40.0 GHz for −10 dB reflection loss) with a small total thickness (5.4 mm). The simulation and experimental results strongly validated the SP-FSS for the design of wide bandwidth electromagnetic wave absorbers.

scholarly journals REASERCH ON A WATER-IMMERSED WIDE BAND HORN ANTENNA WITH WATER-FILLED COAXIAL IMPEDANCE MATCHING STRUCTURE

2019 ◽  
Vol 77 ◽  
pp. 115-123 ◽  
Author(s):  
Yang Yang ◽  
Lianghao Guo ◽  
Qing Zhou ◽  
Zhe Wu ◽  
Haibo Jiang ◽  
...  
Keyword(s):  
Impedance Matching ◽  
Wide Band ◽  
Horn Antenna ◽  
Matching Structure

scholarly journals Development of Three-Phase Permanent-Magnet Synchronous Motor Drive with Strategy to Suppress Harmonic Current

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1583
Author(s):  
Wei-Tse Kao ◽  
Jonq-Chin Hwang ◽  
Jia-En Liu
Keyword(s):  
Permanent Magnet ◽  
Electromotive Force ◽  
Permanent Magnet Synchronous Motor ◽  
Synchronous Motor ◽  
Motor Drive ◽  
Actual Measurement ◽  
Current Harmonic ◽  
Three Phase ◽  
Measurement Results ◽  
Harmonic Components

This study aimed to develop a three-phase permanent-magnet synchronous motor drive system with improvement in current harmonics. Considering the harmonic components in the induced electromotive force of a permanent-magnet synchronous motor, the offline response of the induced electromotive force (EMF) was measured for fast Fourier analysis, the main harmonic components were obtained, and the voltage required to reduce the current harmonic components in the corresponding direct (d-axis) and quadrature (q-axis) axes was calculated. In the closed-loop control of the direct axis and quadrature axis current in the rotor reference frame, the compensation amount of the induced EMF with harmonic components was added. Compared with the online adjustment of current harmonic injection, this simplifies the control strategy. The drive system used a 32-bit digital signal processor (DSP) TMS320F28069 as the control core, the control strategies were implemented in software, and a resolver with a resolver-to-digital converter (RDC) was used for the feedback of angular position and speed. The actual measurement results of the current harmonic improvement control show that the total harmonic distortion of the three-phase current was reduced from 5.30% to 2.31%, and the electromagnetic torque ripple was reduced from 15.28% to 5.98%. The actual measurement results verify the feasibility of this method.

MEASUREMENT OF THE COMPLEX DIELECTRIC CONSTANT OF LIQUIDS AT CENTIMETER AND MILLIMETER WAVELENGTHS

1957 ◽  
Vol 35 (9) ◽  
pp. 995-1003 ◽  
Author(s):  
A. G. Mungall ◽  
John Hart
Keyword(s):  
Dielectric Constant ◽  
Methyl Alcohol ◽  
Free Space ◽  
Normal Incidence ◽  
Complex Dielectric Constant ◽  
Families Of Curves ◽  
Millimeter Wavelengths ◽  
Centimeter Wave ◽  
Space Technique ◽  
Wave Region

The measurement of the complex dielectric constant of lossy liquids in the millimeter and centimeter wave region by a free-space technique is described. The method involves the measurement of absorption per wavelength and of reflectance at normal incidence. Families of curves are given for the relations between these two quantities and the real and imaginary parts of the complex dielectric constant. Results for ethyl and methyl alcohol at 9 and 13 mm. wavelength are compared with those obtained by waveguide techniques.

scholarly journals Parameter Modeling Analysis and Experimental Verification on Magnetic Shielding Cylinder of All-Optical Atomic Spin Magnetometer

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Hong Zhang ◽  
Sheng Zou ◽  
Xi-Yuan Chen ◽  
Wei Quan
Keyword(s):  
Magnetic Measurement ◽  
Magnetic Shielding ◽  
Key Factors ◽  
Actual Measurement ◽  
Atomic Spin ◽  
Modeling Analysis ◽  
Measurement Results ◽  
All Optical ◽  
Ultrahigh Sensitivity ◽  
Shielding Effects

The ultrahigh sensitivity atomic spin magnetometer as the magnetic measurement sensor has received much concern. The performance of the magnetic shielding cylinder is one of the key factors constraining the atomic spin magnetometer’s sensitivity. In order to effectively improve the performances of the magnetic shielding, the parameter optimization models of the magnetic shielding cylinder were established in this paper. Under the condition of changing only one parameter while the others keeping constant, the effects of various parameters influencing the axial shielding coefficient were comprehensively analyzed, and the results showed that the smaller the innermost length, the innermost radius, and the radial spacing were, and the greater the axial spacing was, the better the shielding performance could be obtained. According to these results and the actual needs, the magnetic shielding cylinder was optimally designed, and then the shielding effects were simulated via the software Ansoft. The simulation results showed that the optimized magnetic shielding cylinder had the advantages of small size, high shielding performance, and lager uniformity than that of the nonoptimized one. The actual measurement results showed that the residual magnetism in the optimized magnetic shielding cylinder was below 0.1 nT, which was 2~4 times lower than the nonoptimized one.

scholarly journals Design of PCB Impedance Matching Inductors and Antennas for Single-Chip Communication Systems

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
J. Chung ◽  
S. Hamedi-Hagh
Keyword(s):  
Dielectric Constant ◽  
Resonance Frequency ◽  
Communication Systems ◽  
Return Loss ◽  
Impedance Matching ◽  
Portable Device ◽  
Single Chip ◽  
Matching Network

This paper presents the design of an inductor and an antenna for a portable device with GPS and FM capabilities. The inductor is designed to operate at the lower frequency FM band as part of a matching network and the antenna is designed to operate at the higher frequency GPS L1 band. The FR4 PCB used has a thickness of 1.6 mm with a dielectric constant of 3.8 and has two metallization layers. The inductor is designed with 1.5 mm trace width, 3.5 turns, and has a dimension of 14.5 mm × 14.5 mm. It has an inductance of 95 nH, a resistance of 2.9 Ω, a self-resonance frequency of 500 MHz, and a maximum Q of 51 from 100 MHz to 200 MHz (FM band). The antenna has a dimension of 49 mm × 36 mm and is designed to operate at 1.5754 GHz L1 band. It also has a return loss of −36 dB and a measured bandwidth of 250 MHz.

Microwave Nondestructive Sensing of Moisture Content and Water Activity of Almonds

2021 ◽  
Vol 64 (4) ◽  
pp. 1373-1379
Author(s):  
Samir Trabelsi
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Bulk Density ◽  
Water Activity ◽  
Free Space ◽  
Loss Factor ◽  
Dielectric Loss Factor ◽  
List Type

HighlightsMoisture and water activity were determined nondestructively and in real time from measurement of dielectric properties.Moisture and water activity calibration equations were established in terms of the dielectric properties.Situations in which bulk density was known or unknown were considered.SEC ranged from 0.41% to 0.68% for moisture and from 0.02 to 0.04 for water activity.Abstract. A method for rapid and nondestructive determination of moisture content and water activity of granular and particulate materials was developed. The method relies on measurement of the dielectric constant and dielectric loss factor at a single microwave frequency. For the purpose of illustration, the method was applied to predicting the moisture content and water activity of almond kernels. A free-space transmission technique was used for accurate measurement of the dielectric properties. Samples of Bute Padre almond kernels with moisture content ranging from 4.8% to 16.5%, wet basis (w.b.), and water activity ranging from 0.50 to 0.93 were loaded into a Styrofoam sample holder and placed between two horn-lens antennas connected to a vector network analyzer. The dielectric properties were calculated from measurement of the attenuation and phase shift at 8 GHz and 25°C. The dielectric properties increased linearly with moisture content, while they showed an exponential increase with water activity. Situations in which the bulk density was known and unknown were considered. Linear and exponential growth regressions provided equations correlating the dielectric properties with moisture content and water activity with coefficients of determination (r2) higher than 0.96. Analytical expressions of moisture content and water activity in terms of the dielectric properties measured at 8 GHz and 25°C are provided. The standard error of calibration (SEC) was calculated for each calibration equation. Results show that moisture content can be predicted with SECs ranging from 0.41% to 0.68% (w.b.) and water activity with SECs ranging from 0.02 to 0.04 for almond kernel samples with water activity ranging from 0.5 to 0.9 and moisture contents ranging from 4.8% to 16.5% (w.b.). Keywords: Bulk density, Dielectric constant, Dielectric loss factor, Free-space measurements, Loss tangent, Microwave frequencies, Moisture content, Water activity.

Sign in / Sign up

Export Citation Format

Share Document