EQUIVALENCE BETWEEN CONTINUOUS AND DISCRETE RADIATING ARRAYS

1961 ◽  
Vol 39 (2) ◽  
pp. 335-349 ◽  
Author(s):  
A. Ksienski
Keyword(s):  
The Other ◽  
Radiation Patterns ◽  
Continuous Excitation

The radiation patterns produced by continuous excitation distributions and discrete arrays are compared and the conditions are derived under which one type of source may be substituted for the other with negligible errors. It is shown that the aperture lengths in both cases should be the same but the element spacing is dependent on the type of pattern desired. Examples are computed to demonstrate these relations for both directive patterns and shaped beams.

scholarly journals Research on Resistor-Loaded Half-Ellipse Antenna System for GPR Application

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Xueping Li ◽  
Jinjin Shao ◽  
Yu Zhang
Keyword(s):  
Ground Surface ◽  
Antenna System ◽  
The Other ◽  
Radiation Patterns ◽  
Resistive Loading

A resistor-loaded half-ellipse antenna system mounted on a vehicle as a candidate for the exploration of the lunar subsurface is investigated. The antenna system includes two identical half-ellipse antennas, one is used for transmission, and the other is for reception. A resistive loading technique for broadening the bandwidth and improving impulse radiation is introduced. The performance of the proposed antenna with different height above ground surface is studied, and the influence of the vehicle on the antenna is analyzed. Then the antenna is manufactured and mounted on a vehicle as some tests are done. The simulated and measured antenna VSWR and radiation patterns are compared together, and good agreements between them are achieved.

scholarly journals Design and analysis of stepped reconfigurable rectangular patch antenna for LTE, vehicular and ultra wideband applications

2017 ◽  
Vol 7 (1.1) ◽  
pp. 548
Author(s):  
M Ajay Babu ◽  
B T P Madhav ◽  
G Bhargavi ◽  
V Sai Krishna ◽  
Y Hemanth Kumar Reddy ◽  
...  
Keyword(s):  
Current Distribution ◽  
Patch Antenna ◽  
Single Band ◽  
The Other ◽  
Ultra Wideband ◽  
Radiation Patterns ◽  
Average Gain ◽  
Parasitic Element ◽  
Maximum Gain ◽  
Rectangular Patch

A stepped rectangular patch antenna having partial ground loaded with parasitic element is analyzed in this article. The Proposed antenna is connected to a diode on the flip side of the structure that is in between the parasitic element and the partial ground, the two cases ON, OFF are studied and analyzed. In OFF case the antenna got rejected at 3 bands (2 to 2.3 GHz, 2.6 to 3 GHz and 5.8 to 7.9 GHz). On the other hand, in ON case antenna got rejected at single band (3.6 to 4.4 GHz). The maximum gain of 5.5 dB is observed at 7.8 GHz frequency in ON case and the maximum gain of 4.4 dB is observed at 9 GHz frequency in OFF case with an average gain of 3.3dB in ON case and 2.9dB in OFF case. The proposed antenna works in almost at all ultra wideband applications having single rejection at 3.6GHz-4GHZ.The proposed antenna E-Field, Current distribution and radiation patterns have been analyzed using CST microwave studio in this article.

Generation of Radiation Patterns Equivalent to In-Flight Measurements

2021 ◽  
Vol 35 (11) ◽  
pp. 1298-1299
Author(s):  
Ruben Ortega ◽  
Lauren Jugler ◽  
Yaseman Shiri ◽  
Saad Tabet
Keyword(s):  
Great Circle ◽  
The Other ◽  
Post Processing ◽  
Radiation Patterns ◽  
Bank Angle ◽  
Antenna Radiation ◽  
Other Hand ◽  
Flight Measurements ◽  
Generation Of Radiation

Comparison of in-situ measured antenna radiation patterns (RPs) to modeled ones is vital for validation of both. Inflight measured RPs do not always produce a standard conic or elevation cut (constant θ or ϕ angle, respectively), but rather Great Circle (GC) cuts at the aircraft bank angle of interest. WIPL-D’s post-processing routines, on the other hand, do not produce GC cuts in normal setups. A manipulation of the aircraft orientation in xyz-coordinates is required to accomplish this task. Under standard conditions in WIPL-D, the fuselage is positioned parallel to the x-axis and the wings parallel to the y-axis. A model rotation of 90° with respect to the y-axis allows for the generation of GC cuts, where θ and ϕ swap roles. This makes comparison between in-flight measurements and computed data cumbersome. This paper investigates several options to produce non-standard RPs in WIPL-D and MATLAB (using WIPL-D results) that are equivalent to those of in-flight measurements.

scholarly journals A Novel Design of Parasitically Gap Coupled Patches Forming an Elliptical Patch Antenna for Broadband Performance

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Vijay Sharma
Keyword(s):  
Patch Antenna ◽  
Single Layer ◽  
The Other ◽  
Impedance Bandwidth ◽  
Radiation Patterns ◽  
Central Frequency ◽  
Elliptical Shape ◽  
Resonant Modes ◽  
Novel Design ◽  
Layer Assembly

A novel single layer assembly of gap coupled elements in elliptical shape is proposed in this communication to achieve broadband performance. Among the five patches considered in the present assembly, two pairs of patches having different patch areas are arranged around an edge truncated elliptical patch. The central edge truncated elliptical patch is fed through an inset feed arrangement and the other patches are parasitically gap coupled to the central patch. With such an arrangement, an enhanced impedance bandwidth of 2.45 GHz (or 36.2%) with respect to central frequency 6.1 GHz is achieved. Three resonant modes are excited with this arrangement giving improved bandwidth and gain in comparison to a conventional elliptical patch antenna. The simulated radiation patterns of proposed arrangement of patches suggest that these are identical in shape and direction of maximum radiations is directed normally to assembly of patches.

scholarly journals Metamaterial Loaded Elliptical Ring Structured Mimo Antenna

2019 ◽  
Vol 8 (6) ◽  
pp. 1798-1801
Keyword(s):  
Dielectric Constant ◽  
Return Loss ◽  
The Other ◽  
Radiation Patterns ◽  
Mimo Antenna ◽  
Elliptical Ring

The article proposes a MIMO isolation enhanced MIMO antenna for LTE bands, Bluetooth and Wi-Fi. The antenna is consisting of two radiating elements, where two are similar radiating elements separated by a distance. Another patch element is also added to create the peaks in the return loss. The antenna designed is working in the bands 1.29GHz-3.98GHz, 7.12GHz-8.09GHz, 14.01GHz-15.82GHz and 17.64GHz-20GHz. It has achieved good gain in the working bands of the antenna. The antenna is fabricated on 50×60×1.6 mm^3 FR-4 substrate with dielectric constant of 4.4. The antenna is analyzed and simulated using Ansys electromagnetic desktop 18. The other parameters such as gain, radiation patterns etc. are also discuss

scholarly journals Coplanar Stripline Loaded Reconfigurable Loop Antenna for WLAN and WiMAX Applications

2018 ◽  
Vol 8 (5) ◽  
pp. 3479-3483
Author(s):  
S. P. R. Shastri ◽  
R. R. Singh ◽  
K. V. Ajetrao
Keyword(s):  
Size Reduction ◽  
The Other ◽  
Loop Antenna ◽  
Dual Band ◽  
Radiation Patterns ◽  
Multiband Antenna ◽  
Coplanar Stripline ◽  
Stationary Radiation ◽  
Loop Antennas ◽  
Good Agreement

In this paper, a loop antenna loaded with coplanar strip (CPS) line is proposed as a multiband antenna. The CPS line is added with two switches to vary the antenna perimeter to cover seven different bands. The CPS line introduced into the loop is not only useful in reconfiguring antenna dimensions but also provides stationary radiation patterns for the all the covered bands. The proposed antenna works in single and dual-band modes. When the proposed antenna works as a single band antenna, it produces a band from 4.2GHz to 5.7GHz. Under dual-band operation, it produces bands from 3.75GHz to 4.7GHz and from 6.4GHz to 7.8GHz. The other dual-band mode ranges from 3.5GHz to 3.8GHz and from 5.58GHz to 7.4 GHz. The simulated and measured results are in good agreement and the proposed antenna can be used satisfactorily for W-LAN and WiMax applications. The proposed technique can also be used for size reduction of loop antennas.

Stromatoporoids from the Famennian (Devonian) Wabamun Formation, Normandville oilfield, north–central Alberta, Canada

1988 ◽  
Vol 62 (03) ◽  
pp. 411-419 ◽  
Author(s):  
Colin W. Stearn
Keyword(s):  
Patch Reef ◽  
Abundant Species ◽  
The Other ◽  
North Central ◽  
Biotic Crisis

Stromatoporoids are the principal framebuilding organisms in the patch reef that is part of the reservoir of the Normandville field. The reef is 10 m thick and 1.5 km2in area and demonstrates that stromatoporoids retained their ability to build reefal edifices into Famennian time despite the biotic crisis at the close of Frasnian time. The fauna is dominated by labechiids but includes three non-labechiid species. The most abundant species isStylostroma sinense(Dong) butLabechia palliseriStearn is also common. Both these species are highly variable and are described in terms of multiple phases that occur in a single skeleton. The other species described areClathrostromacf.C. jukkenseYavorsky,Gerronostromasp. (a columnar species), andStromatoporasp. The fauna belongs in Famennian/Strunian assemblage 2 as defined by Stearn et al. (1988).

D. The Line Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 207-244
Author(s):  
R. P. Kraft
Keyword(s):  
Variable Stars ◽  
The Other ◽  
Line Spectrum ◽  
Afternoon Session ◽  
Empirical Information ◽  
Pulsating Variable Stars ◽  
Almost Continuous ◽  
Informal Approach

(Ed. note:Encouraged by the success of the more informal approach in Christy's presentation, we tried an even more extreme experiment in this session, I-D. In essence, Kraft held the floor continuously all morning, and for the hour and a half afternoon session, serving as a combined Summary-Introductory speaker and a marathon-moderator of a running discussion on the line spectrum of cepheids. There was almost continuous interruption of his presentation; and most points raised from the floor were followed through in detail, no matter how digressive to the main presentation. This approach turned out to be much too extreme. It is wearing on the speaker, and the other members of the symposium feel more like an audience and less like participants in a dissective discussion. Because Kraft presented a compendious collection of empirical information, and, based on it, an exceedingly novel series of suggestions on the cepheid problem, these defects were probably aggravated by the first and alleviated by the second. I am much indebted to Kraft for working with me on a preliminary editing, to try to delete the side-excursions and to retain coherence about the main points. As usual, however, all responsibility for defects in final editing is wholly my own.)

C. The Continuous Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 177-206
Author(s):  
J. B. Oke ◽  
C. A. Whitney
Keyword(s):  
Continuous Spectrum ◽  
Variable Stars ◽  
Velocity Fields ◽  
The Other ◽  
Line Spectrum ◽  
Direct Information ◽  
Thermodynamic Structure ◽  
Diagnostic Interpretation ◽  
Pulsating Variable Stars ◽  
The Continuum

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.

Observing programme for the 24-inch/36-inch Schmidt telescope

1966 ◽  
Vol 24 ◽  
pp. 337
Author(s):  
W. Iwanowska
Keyword(s):  
The Other ◽  
Schmidt Telescope ◽  
Flint Glass

A new 24-inch/36-inch//3 Schmidt telescope, made by C. Zeiss, Jena, has been installed since 30 August 1962, at the N. Copernicus University Observatory in Toruń. It is equipped with two objective prisms, used separately, one of crown the other of flint glass, each of 5° refracting angle, giving dispersions of 560Å/mm and 250Å/ mm respectively.

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