Читать книгу Spatial Multidimensional Cooperative Transmission Theories And Key Technologies - Lin Bai - Страница 37

In 1953, T.T. Taylor presented a pattern synthesis method derived from the uniform excitation array pattern sin(πu)/πu. The zero interval of the pattern is an integer, and the descent velocity of sidelobe envelope is 1/u. Therefore, it is necessary to control the height of the first sidelobe level, which is realized by adjusting the zero point of the pattern function. The zero point of the array pattern is given by .

B is an undetermined parameter and then the description of the antenna pattern becomes

when u = B, the pattern changes from a hyperbolic function to a sinc function.

SLR is the ratio of peak to sinc, and it is expressed in dB by

The method determines all parameters of the pattern by a single parameter B, including sidelobe level, beamwidth, and beam efficiency. The aperture distribution of the array is the inverse of the pattern, i.e.

where p is the distance from the center of the aperture to one end and I₀ is the modified Bessel function. The excitation efficiency is

where is the list integration.

When using this method, B is calculated from Eq. (2.86) according to the SLR of the designed pattern, and the excitation value of the array is obtained from the aperture distribution equation. The characteristic parameters of the Taylor single-parameter pattern synthesis are shown in Table 2.1.

In addition to the two methods described above, the analytical methods for antenna pattern synthesis also include Taylor n, Villenenve n, and so on. The analytical methods for planar array pattern synthesis include Hansen single-parameter circle distribution, Taylor n circle distribution, and so on.