Statistical Analysis for Time Modulation-Based Frequency Diverse Array Beampattern

Abstract

Frequency diverse array (FDA) has received much attention due to its both range-and angledependent beampatterns. However, the range-angle coupling and time-variant beampattern in FDA may affect its applicability. In order to address the beampattern range-angle coupling problem and time variance, many existing algorithms, by using the time-modulated optimized frequency offset (TMOFO) scheme, are presented to obtain the spatial-focusing time-invariant transmit beampattern synthesis for the FDA. To discuss their irrationality, we first give a time-modulated optimized weight vector (TMOWV) scheme with frequency offset optimization, which is a more general time-modulated scheme for the FDA beampattern synthesis and more convenient for the statistical analysis of the designed FDA transmit beampattern characteristics. Then, the statistical analysis of the designed FDA transmit beampattern is investigated through both theoretical derivations and numerical examples. The extensive simulation results demonstrate that the time-modulated approach for the time-invariant FDA transmit beampattern is invalid. INDEX TERMS Frequency diverse array, transmit beamforming, time-modulated array, time-variant, beampattern synthesis.

Nonlinear Frequency Offset Beam Design for FDA-MIMO Radar

“…Since the first introduction of FDA radars in [ 1 ], the important property that their beam patterns are range-dimension dependent and can vary with time has been discovered, which has attracted extensive attention from scholars home and abroad. When the time and frequency offsets are fixed, the emission direction pattern of the frequency-controlled array has a range–angle-dependent property, which is more flexible compared with the conventional phased array and has a very high potential in practical applications [ 2 , 3 , 4 , 5 , 6 ]. However, the conventional fixed-frequency offsets FDA emission direction diagram is “S” shaped, with range–angle coupling characteristics, and is time-varying, which is unfavorable for the practical application of radar.…”

Analysis of beampattern dwell time for planar frequency diverse array

“…To address this problem, a quasi-static beampattern is obtained by solving a convex optimization problem [15] or adding a constraint to alleviate the time-variant beampattern [16]. Besides, several time-invariant beampattern design schemes have been proposed [17,18] by using timemodulated frequency offset, which has been proved impossible by the studies [19][20][21][22]. What is more, only qualitative analysis is studied for the time-varying FDA beampattern in the latest relevant research.…”

FDA-MIMO Beampattern Synthesis with Hamming Window Weighted Linear Frequency Increments

“…Owing to its ability of range-angle-dependent, the FDA has exceptional application potential in radar and navigation [5][6][7]. Many studies about FDA have been presented in recent years [8][9][10][11][12][13][14][15][16][17]. Many researchers take their exploration in getting rid of the disadvantages of FDA beampattern such as range-angle coupling [18][19][20] and time-variant [21,22].…”