Taylor Patterns Research Articles

Measurement distance effects on -symmetric Taylor patterns with optimal transition integer and with reduced inner sidelobes

The following paper presents the findings of a study conducted on the distances at which the field generated by a -symmetric circular Taylor aperture distribution can be classified as far-field, and also the efficiency across various study parameters. The transition integers that produce a monotonic distribution, which have been traditionally used and analyzed, are compared with those that yield a peaked distribution, and offer greater efficiency. Additionally, modified circular Taylor distributions featuring synthesized patterns with one or two depressed inner sidelobes, which have not been previously explored, are also examined.

An Improved Pattern Synthesis Iterative Method in Planar Arrays for Obtaining Efficient Footprints with Arbitrary Boundaries.

In the present paper, an iterative technique devoted to reproducing efficient footprints with arbitrary boundaries for planar arrays is addressed. The methodology here depicted is based on exploiting the nature of the continuous aperture distribution by expressing it as a Fourier series of moderately high orders. In this manner, the resulting illumination boundary is defined by a target three-dimensional flat-topped pattern composed of stretching and shrinking modified circular Taylor patterns and the maximum order of the series to obtain a good reconstruction is determined by means of the iterative process. Examples and comparisons with the previous literature were conducted by analyzing square and rectangular contoured beams as test cases. Additionally, interesting potentials regarding space applications from a geostationary satellite are outlined by means of the EuTELSAT (European Telecommunications Satellite Organization) European coverage case study. In such a way, its numerical approach was analyzed by including subarray architectures and discussing improvements about dynamic range ratio of the excitations without critical power losses within the illumination region.

Synthesis of Nonuniformly Spaced Linear Arrays With Frequency-Invariant Patterns by the Generalized Matrix Pencil Methods

This work extends the matrix pencil method (MPM)-based synthesis technique to the case of nonuniformly spaced linear arrays with wideband frequency-invariant (FI) patterns. A new sampling strategy is proposed to obtain multiple pattern data of different frequencies having the same poles that correspond to the FI element positions. The obtained multiple pattern sequences have the same shape for the FI pattern requirement, but with different lengths. The generalized MPM (GMPM) and its forward-backward version (GFBMPM) are developed to estimate the best common element positions for different frequencies, which can significantly reduce the number of elements required for the specified wideband pattern shape. The element excitations are solved by the regularized least-square (LS) method at each frequency. Then, an efficient method by utilizing the FFT is presented to obtain real-coefficient finite-impulse-response (FIR) filters for implementing the frequency-varying excitations. A set of numerical examples for the FI synthesis of pencil-beams, shaped patterns, scannable patterns, and Taylor patterns with low SLLs are presented to validate the effectiveness and advantages of the proposed methods. The element saving is about 11.2%-49.4% for usual cases.

Rapid method for obtaining footprint patterns for very large antenna arrays

A new antenna pattern synthesis technique that allows the design of large planar antenna array radiating footprint patterns of a specified boundary with controlled ripple and sidelobe levels is presented. The method synthesises the desired footprint as a composition of a set of circular Taylor patterns appropriately weighted with the samples of the pattern obtained after stretching or shrinking a continuous circular aperture distribution developed by the Elliott-Stern method. A footprint of continental Europe radiated by a planar array with a large number of elements shows the technique's performance. The synthesis procedures were completed in about 1 s using a desktop computer.

Quasi-Analytical Synthesis of Moderate and Large Arrays Radiating Arbitrary "Star-Shaped" Footprint Patterns [Antenna Designer's Notebook

The proposed quasi-analytical method undertakes the shaping of a desired footprint as a composition of several phi-symmetric circular Taylor patterns exhibiting flat-topped beams. The final pattern is obtained after sampling the circular aperture that is obtained for rectangular-grid planar arrays. A triangular-shaped footprint and a footprint of continental Europe, radiated by planar arrays with moderate and large numbers of elements, show the technique's performance.

Arbitrary footprint patterns obtained by circular apertures

The proposed quasi-analytical method undertakes the shaping of a desired footprint as a composition of several /spl phi/-symmetric circular Taylor patterns exhibiting flat-topped beams. The final pattern is obtained after sampling the obtained circular aperture for circular grid planar arrays. A square and a rectangular footprint pattern, both radiated by a planar array with 1246 elements, demonstrate the performance of the technique.

Optimal Synthesis Of Circular Apertures Based On Ludwig Distributions

Ludwig distributions are a generalization of circular Taylor distributions that generate radiation patterns with wide-angle side lobe levels decaying faster than for Taylor patterns. In this paper we show that by means of an appropriate optimization technique the zeros of Ludwig patterns can be perturbed so as to improve or modify pattern and/or aperture distribution characteristics without altering the wide-angle decay behavior. The examples presented include footprint patterns, pencil beam patterns with individually controlled side lobe heights, footprint beams generated by real excitations, and pencil beam patterns with aperture distributions that are smoother than the original Ludwig distribution.

Asymmetric-shaped beam patterns from a continuous linear aperture distribution

A design method previously developed to give symmetrical shaped patterns from a continuous linear aperture, with individual control of the amplitude of ripples and the heights of unshaped side lobes up to any specified order, is shown to be applicable to asymmetric patterns as well. The method is based on the introduction of complex roots (to achieve null filling in the shaped region) in the technique previously developed by R. S. Elliott to obtain asymmetric Taylor patterns. Power synthesis, where the radiation pattern becomes complex, and real field synthesis, which yields a pure real pattern, are studied. The procedure is illustrated with two examples corresponding to a cosecant squared pattern, obtained by power and real field synthesis, respectively. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 15: 288–291, 1997

Taylor patterns for discrete arrays

The equivalent of a Taylor pattern for continuous apertures is developed for discrete arrays. This array factor can be realized exactly, since it belongs to the appropriate class of patterns. A method for determining the element excitations is also presented. As an example, the pattern and excitations are calculated for a 41-element array with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\bar{n} = 6</tex> and a 25 dB design sidelobe level. Comparison is made with the patterns obtained by applying root matching and sampling of a continuous Taylor aperture.

Design of array and line-source antennas for Taylor patterns with a null

An antenna pattern design technique which results in a generalized Taylor pattern, except in a narrow region where a deep null is formed, centered at a preassigned position is presented. It is shown how this technique can be applied effectively to both linear arrays and line sources. The approach is direct so that the technique does not use either iterative sampling or a perturbation procedure. It is particularly useful in the design of a large array with a prescribed deep null. Numerical results indicate that to steer such a null, adjustment of the excitation is necessary near the edges only.

Design of circular apertures for narrow beamwidth and asymmetric low sidelobes

Taylor's earlier work on circular apertures is enlarged to include a class of radiation patterns consisting of a narrow central beam and asymmetric sidelobes. A synthesis technique applicable to such problems, and using Taylor patterns as building blocks, is formulated. One special case is treated in detail: a sidelobe topography which is 25 dB down in the \phi = 0 half-plane, smoothly rising to 15 dB down in the \phi= \pi/2 half-plane, remaining at that level until the \phi = 3\pi/2 half-plane is reached, and then smoothly subsiding to 25 dB again as \phi increases from 3\pi/2 to 2\pi . The complex aperture distribution is derived generally, and exhibited specifically for this case.

Directive Gain of Circular Taylor Patterns

The directive gain of circular Taylor patterns is determined. It is shown that so‐called optimum patterns, i.e., uniform sidelobes in all planes, are severely limited for planar apertures because of excessive sidelobe power. The optimum directive gain of the circular Taylor pattern with a given sidelobe level can be obtained by appropriate design.

On the synthesis of concentric-ring arrays

It is shown that the radiation pattern of a circular aperture antenna can be closely approximated by a concentric ring array with sampled amplitudes. The maximum allowable inter-ring spacing is found to be about four-tenths of a wavelength if high side-lobes are to be avoided. Taylor patterns are used as examples.

A Technique for the Synthesis of Line-Source Antenna Patterns Having Specified Sidelobe Behavior

A new method for the synthesis of line.source antenna patterns having prescribed sidelobe envelope functions is discussed. The patterns obtained are inherently nonsupergained and, in the sense of Taylor patterns, approach the narrowest beamwidth for the given sidelobe behavior. Sample patterns and corresponding aperture distributions, together with required design parameters, are given. The sidelobe envelope functions for those patterns having maximum gain for a given maximum sidelobe level are also presented.