Bidirectional beam forming method based on time modulation linear array

Abstract

The invention discloses a bidirectional beam forming method based on a time modulation linear array. The method comprises the following steps: constructing an array factor of a time modulation lineararray capable of forming a bidirectional beam; calculating the switching time of each array element in the time modulation linear array according to the required sidelobe, beam pointing and null direction; carrying out modulation by switching time to form a bidirectional wave beam. According to a traditional beam forming method of a time modulation linear array, a single sequence is adopted for successive scanning, and the mode is low in efficiency and can only control a single beam. Based on time sequence offset, a plurality of sequences are adopted for simultaneous scanning, so that bidirectional +1 harmonic waves are generated, a hardware structure does not need to be improved, and the available harmonic wave direction is increased while the cost is saved. In addition, fundamental wavesare added, beams in three directions can be generated at most, and the purpose of efficient and low-cost multi-beam forming is achieved.

Description

technical field [0001] The invention belongs to the field of array signal processing, in particular to a two-way beam forming method based on a time-modulated linear array. Background technique [0002] The time-modulated array uses radio frequency switches instead of phase shifters to change the phase of the beam to complete beamforming. Compared with the phased array, its hardware structure is simpler and has been extensively studied at present. Time modulated arrays can achieve low sidelobe beam patterns by optimizing the time sequence. [0003] Harmonic multibeams generated by time-modulated arrays can be used in many fields, including communications, detection, and target location. At present, there are many researches on harmonic multi-beams, such as using the fundamental wave and +1, +2 harmonics to form multi-beams, or using ±1 harmonics and fundamental waves to generate multi-beams. [0004] According to the characteristics of the Fourier series, as the order of t...

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Problems solved by technology

[0004] According to the characteristics of the Fourier series, as the order of the harmonic becomes higher, its energy becomes smaller and smaller, so in practice only the +1 harmonic can be used, which makes a large number of applications based on high-order harmonics extremely difficult. difficulty

By improving the hardware structure, the energy of harmonics can be increased, but this will increase the cost of the system; and by optimizing the time series, only the energy of a certain harmonic can be increased

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