Theory of Unequally Spaced Arrays PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Theory of Unequally Spaced Arrays PDF full book. Access full book title Theory of Unequally Spaced Arrays by Akira Ishimaru. Download full books in PDF and EPUB format.
Author: Akira Ishimaru
Publisher:
ISBN:
Category : Antenna arrays
Languages : en
Pages : 36
Get Book Here
Book Description
A new approach to the array problem is shown which is particularly suited for unequally spaced arrays with a large number of elements which may be located on a line or on a curve. It is shown that an unequally spaced array of uniform amplitude with any desired sidelobe level may be designed using our method. Also, the secondary beam suppression and the azimuth frequency scanning circular array was discussed to show the effectiveness of the method. Other applications including unequally spaced array on a travelling wave waveguide, the amplitude modulated antennas, the leaky-wave antennas, and the frequency scanning linear antennas are discussed. (Author).
Author: Akira Ishimaru
Publisher:
ISBN:
Category : Antenna arrays
Languages : en
Pages : 36
Get Book Here
Book Description
A new approach to the array problem is shown which is particularly suited for unequally spaced arrays with a large number of elements which may be located on a line or on a curve. It is shown that an unequally spaced array of uniform amplitude with any desired sidelobe level may be designed using our method. Also, the secondary beam suppression and the azimuth frequency scanning circular array was discussed to show the effectiveness of the method. Other applications including unequally spaced array on a travelling wave waveguide, the amplitude modulated antennas, the leaky-wave antennas, and the frequency scanning linear antennas are discussed. (Author).
Author: Marc I. Spellman
Publisher:
ISBN:
Category : Antenna arrays
Languages : en
Pages : 24
Get Book Here
Book Description
It is shown that under certain conditions, Z-transform theory can be applied to simplify analysis and synthesis of unequally spaced antenna arrays. The approach provides significant advantages over other techniques since the method yields closed-form expressions for array factors that are otherwise often cumbersome and difficult to work with analytically. The method is useful for both broadside and endfire arrays and allows many of the result originally derived for equally spaced arrays to be applied.
Author: Jack Niilo Lahti
Publisher:
ISBN:
Category : Antenna arrays
Languages : en
Pages : 40
Get Book Here
Book Description
The paper deals with the problems encountered when one wishes to synthesize a specified radiation pattern with a unequally spaced array which utilizes a traveling wave feed system. A differential equation is developed which relates the amplitude distribution to the source position function of such an array. Solutions of this equation are found which allow the synthesis of a broad class of radiation fields. The theory is used to design a traveling wave fed unequally spaced array to produce the 'cosecant squared' pattern. Theoretical and experimental results are observed to be in good agreement. (Author).
Author: Harvey K. Schuman
Publisher:
ISBN:
Category : Antenna arrays
Languages : en
Pages : 156
Get Book Here
Book Description
Analytical techniques presented thus far for treatment of unequally spaced antenna arrays have pointed out that desirable radiation characteristics can be achieved using only the interelement spacings as design parameters. The advantage is that the excitation amplitudes required can be either uniform or nearly uniform across the array, thereby allowing use of a simple feed system for excitation of the array elements and minimizing adverse mutual coupling effects. The design methods have found only limited applications, however, since results are not always reliable due to the approximations necessary to simplify the analytical work. Various computational methods have been presented to circumvent this problem, but these in turn suffer disadvantage in that they provide no control over the ultimate positions of the array elements, giving rise to unrealistic spacing configurations and severe realization problems through mutual coupling. In this work a new computational technique is presented for designing unequally spaced arrays. The method is particularly suitable for use with modern high-speed electronic computers, and allows certain practical restrictions or constraints to be included in the design procedure by allowing use of a limited number of different excitation amplitude levels. The result in any given example is an unequally spaced linear array designed for a specified sidelobe level, with a number of amplitude levels appropriate for insuring that prespecified spacing restrictions are met. Thus, the practical difficulties encountered with the results of other computational schemes are largely avoided. Several examples are given, and both theoretical and experimental results are included. (Author).
Author: Raymond Henry West
Publisher:
ISBN:
Category : Arrays
Languages : en
Pages : 110
Get Book Here
Book Description
Author: Andrew K. Chan
Publisher:
ISBN:
Category : Antenna arrays
Languages : en
Pages : 45
Get Book Here
Book Description
The report presents a new method of analyzing the radiation characteristics of a spherical array. The existing method of finding the characteristics of an array on a curved surface using computers does not provide a means of predicting the sidelobe level and beamwidth of the pattern. In this report, the theory of unequally spaced arrays developed by Ishimaru is applied to this problem and the radiation characteristic is found to behave as sin(u)/u. The elements of the array are arranged as a series of circular arrays of different radii on the spherical surface. The resulting radiation pattern for constant amplitude and element spacing of one wave length is discussed in detail. The validity of the theory is demonstrated by an experimental spherical array which employs half-wavelength dipole elements on an Eccoform sphere. Due to the difficulty of exciting each element of the array a plane wave is used to excite the array. Scattered wave is measured and compared with the theory. (Author).
Author: Akira Ishimaru
Publisher:
ISBN:
Category : Antenna arrays
Languages : en
Pages : 42
Get Book Here
Book Description
The paper presents a theory for, and a method of designing a thinned or broadband antenna array by means of unequal spacings. Using the theory of unequally spaced arrays developed by one of the authors, an antenna array can be designed to produce a desired beamwidth and sidelobe level with the average spacing many wavelengths apart. The patterns are expressed in a series of the Anger functions and its sidelobe level is shown to decrease approximately as N to the minus 0.4th power where N is the total number of elements, and the gain is approximately equal to N. It is also shown that the sidelobe level can be improved by varying the amplitude distribution. Numerical examples are given to illustrate the method. (Author).
Author: Peter Paul Ilacqua
Publisher:
ISBN:
Category : Antenna arrays
Languages : en
Pages : 178
Get Book Here
Book Description
Author: Richard Paul Dooley
Publisher:
ISBN:
Category :
Languages : en
Pages : 192
Get Book Here
Book Description
Author: Hema Singh
Publisher: Cambridge University Press
ISBN: 1107092612
Category : History
Languages : en
Pages : 354
Get Book Here
Book Description
This book discusses the active and passive radar cross section (RCS) estimation and techniques to examine the low observable aerospace platforms. It begins with the fundamentals of RCS, followed by the dielectric, magnetic and metamaterials parameters of the constituent materials and then explains various methods and the emerging trends followed in this area of study. The RCS estimation of phased array including the mutual coupling effect is also presented in detail in the book. The active RCS reduction is carefully touched upon through the performance of phased arrays, sidelobe cancellers and mitigation of multipath effect. Providing information on various adaptive algorithms like least mean square (LMS), recursive least square (RLS) and weighted least square algorithms, the authors also mention the recent developments in the area of embedded antennas, conformal load bearing antenna, metamaterials and frequency selective surface (FSS) based RCS reduction.
