scholarly journals Study on the Relationships between Eigenmodes, Natural Modes, and Characteristic Modes of Perfectly Electric Conducting Bodies

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Shaode Huang ◽  
Jin Pan ◽  
Yuyue Luo
Keyword(s):  
Circular Cylinder ◽  
Rectangular Plate ◽  
Radiation Patterns ◽  
Resonant Frequencies ◽  
Natural Modes ◽  
Electric Conducting ◽  
Electromagnetic Power ◽  
Characteristic Modes ◽  
Conducting Bodies ◽  
Internal Resonant

We specify the corresponding relationships between eigenmodes, natural modes, and characteristic modes of perfectly electric conducting (PEC) bodies. The internal resonant frequencies, external resonant frequencies, current distributions, and radiation patterns of the three kinds of modes are compared to identify the relationships. Firstly, we review the definitions of the three kinds of modes and discuss their characteristics of the electromagnetic power. After that, we illustrate the relationships between these modes with three typical structures, that is, the infinite circular cylinder, sphere, and rectangular plate.

scholarly journals A Compact ACS-Fed Tri-band Microstrip Monopole Antenna for WLAN/WiMAX Applications

2018 ◽  
Vol 7 (5) ◽  
pp. 87-93 ◽  
Author(s):  
D. Kahina ◽  
C. Mouloud ◽  
D. Mokrane ◽  
M. Faiza ◽  
A. Rabia
Keyword(s):  
Radiation Pattern ◽  
Return Loss ◽  
Simple Structure ◽  
Ground Plane ◽  
Monopole Antenna ◽  
Radiation Patterns ◽  
Total Size ◽  
Resonant Frequencies ◽  
Compact Size ◽  
Microstrip Monopole Antenna

This paper proposes a novel small asymmetric coplanar strip (ACS) fed tri-band monopole antenna for WLAN and WiMAX applications. To tune and create multiple resonant frequencies, the exciting strip of monopole antenna is connected to two different arms which are a J-shaped directed toward the asymmetric ground plane and an open stub. The proposed monopole antenna with a total size of 14.6 x17.5 mm2 is fabricated and tested. The measured results indicate that the antenna has impedance bandwidths for 10-dB return loss reach about 500 MHz (2.01-2.52 GHz), 230 MHz (3.48-3.71 GHz) and 1.2GHz (5.59-6.72 GHz) which cover widely the 2.4/5.8 GHz WLAN bands and the 3.5GHz WiMAX band. The simulated radiation patterns of the proposed antenna at the three resonant frequencies have a dipole-like radiation pattern in both E-and H-Planes. The compact size, the simple structure and good radiation performances of the proposed antenna makes it well-suited forthe intended applications.

scholarly journals A Comparative Study of Compact Multiband Bio-Inspired Asymmetric Microstrip Fed Antennas (BioAs-MPAs) for Wireless Applications

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Jeremiah O. Abolade ◽  
Dominic B. O. Konditi ◽  
Vasant M. Dharmadhikary
Keyword(s):  
Carica Papaya ◽  
Aviation Industry ◽  
Radiation Patterns ◽  
Defected Ground Structure ◽  
Ground Structure ◽  
Resonant Frequencies ◽  
Wireless Applications ◽  
Monstera Deliciosa ◽  
Aerial Vehicle ◽  
First Time

A comparative analysis of compact multiband bio-inspired Asymmetric microstrip fed antennas (BioAs-MPAs) is presented in this paper for the first time. The proposed antennas are based on semi-Carica papaya-leaf shaped, semi-Monstera deliciosa-leaf shaped, semi-Vitis vinifera shaped, Defected Ground Structure (DGS) and L-slit techniques. The antennas are built on a 33 × 15 mm2 Rogers duroid 5880 substrate. The modelling equations for resonant frequencies of the proposed arbitrarily shaped radiating patch is based on modified circular patch modelling equations. The semi-Carica papaya-leaf antenna operates at 2.4 GHz and 4.4 GHz, Monstera deliciosa-leaf antenna operates at 2.6 GHz, 4.4 GHz and 5.5 GHz, while Vine-leaf antenna operates at 2.5 GHz and 5.4 GHz. The proposed BioAs-MPAs antennas radiation patterns at E-plane are Bi-directional in all the operating frequencies with suitable X-Pol purity and have Omnidirectional radiation patterns at H-Plane in all the operating frequencies. As a result of the analysis, it was found that each of the bio-inspired structures has its unique merit over the others. Owing to the small size, stable radiation pattern, acceptable gain and high radiation efficiency, the proposed BioAs-MPAs antennas are suitable for ISM band, Bluetooth, Wi-Fi, WiMAX, LTE, UMTS, Sub6 GHz 5 G band, ZigBee and RF-Altimeter used in unmanned aerial vehicle and Aviation industry.

scholarly journals Technology of Ground Vibration Testing and its application in light aircraft prototyping

2019 ◽  
Vol 304 ◽  
pp. 01005
Author(s):  
Aleksander Olejnik ◽  
Stanisław Kachel ◽  
Robert Rogólski ◽  
Michał Szcześniak
Keyword(s):  
Early Stage ◽  
Ground Vibration ◽  
Measuring System ◽  
Vibration Measurement ◽  
Measurement Technology ◽  
Vibration Testing ◽  
Resonant Frequencies ◽  
Natural Modes ◽  
University Of Technology ◽  
The Military

The article describes the vibration measurement technology used for light aircraft and some results obtained during the prototyping process. The aim of researches was to determine the resonant frequencies and natural modes of an aircraft or its selected structural components. Ground Vibration Testing is an essential dynamic structural test necessary to carry out before the aircraft certification. This test should be performed on the aircraft example which is predicted to test in flight. The measuring system used in the Institute of Aviation Technology of the Military University of Technology consists of a multi-channel LMS SCADAS analyzer, a set of piezoelectric accelerometers, two vibration exciters equipped with impedance heads and a computer with the Test.Lab Software. The aim of the article is to present the methodology of performing GVT tests. Using the equipment applied to an aircraft or its airframe component, key vibration characteristics corresponding to resonant points can be determined. Not only completed aircraft can be tested, but also its isolated fragments (wings, stabilizers, tail units) or just empty airframe. Testing separately supported components allows to examine their aeroelastic properties at early stage of prototyping. As examples of the use of vibration measurements in various stages of the prototyping process, three examples are presented herein. The isolated strut-braced wing from of the light reconnaissance aircraft OSA, the airframe of a light jet FLARIS LAR, and the light drone ATD JET-2 intended to be an aerial target for some anti-aircraft artillery sets. Some exemplary results obtained from testing these objects were presented. At the end, some observations and conclusions were noted in the context of usefulness of conducted researches.

Vibration Isolation Characteristics of Euler Strut Spring Used in Low Frequency Vibration Isolation System

2012 ◽  
Vol 248 ◽  
pp. 475-480
Author(s):  
Guan Jun Zhang ◽  
Xiang Zhu ◽  
Ran Xu ◽  
Tian Yun Li
Keyword(s):  
Vibration Isolation ◽  
Structural Parameters ◽  
Low Frequency ◽  
Resonant Frequencies ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Low Frequency Vibration ◽  
Steel Material ◽  
Internal Resonant ◽  
Spring Maximum

Recently, the Euler strut is used as the supporting spring in the low frequency isolation. An Euler spring is a column or strut of steel material which is compressed elastically beyond its buckling load, which makes the ratio of the isolated mass to the mass of the supporting spring maximum, and greatly increasing the internal resonant frequencies of the isolator. In this research, the unique mechanical properties and the expressions of the displacement transmissibility of the Euler strut are deduced. The influences of structural parameters of the strut on the stiffness and vibration isolation characteristics are investigated in detail. The results show that the Euler strut has the potential in low frequency vibration isolation, and the length and breadth of the strut can influence the stiffness, transmissibility and critical loading mass respectively.

PATTERNS OF STUB ANTENNAS ON CYLINDRICAL STRUCTURES

1956 ◽  
Vol 34 (2) ◽  
pp. 190-202 ◽  
Author(s):  
James R. Wait ◽  
K. Okashimo
Keyword(s):  
Circular Cylinder ◽  
Half Plane ◽  
Experimental Results ◽  
Infinite Length ◽  
Radiation Patterns ◽  
Cylindrical Structures ◽  
Electric Dipoles ◽  
Perfect Conductivity

Theoretical radiation patterns are presented for radial electric dipoles located on an isolated circular cylinder, and a cylindrically tipped half-plane. These cylindrical structures are considered to be of infinite length and of perfect conductivity. The computed patterns for the isolated cylinder compare well with the experimental results reported by Bain.

Sign in / Sign up

Export Citation Format

Share Document