A device for generating millimeter-wave Bessel beams using dual feeds

Abstract

The invention discloses an apparatus for generating a Bessel beam using a double feed source. The apparatus comprises two identical feeds and a lens located on a plane. The geometrical centers of theexit surfaces of the two feeds are equal to the distance from the focal point of the lens, and the two feeds are dielectric rod antennas for incident the generated two Gaussian beams onto the lens foroutputting the Bessel beams. The device of the invention utilizes two identical feed sources, solves the problem of beam splitting in the traditional method, directly utilizes two beams for coherentmodulation to obtain a Bessel beam, the whole device is simple and practical, and the length thereof is shortened by 20% compared with the existing device.

Description

technical field [0001] The invention belongs to the technical field of millimeter wave applications, and in particular relates to a device for generating Bessel beams by using double feed sources. Background technique [0002] In the visible and infrared fields, Gaussian beams are often used for collimation and cutting operations. At the same time, Gaussian beams are expected to have the characteristics of small diffraction angle and small beam radius. However, in practical applications, the beam divergence angle and diffraction angle show an anti-correlation relationship. Therefore, people have been looking for a way to make the laser beam not diffracted or not diffracted within a certain transmission distance. In 1987, American scientists first introduced the concept of "non-diffraction beam" and obtained it in theory and experiments. Verification, it has been proved theoretically that the non-diffraction beam in the absolute sense is impossible to exist, but in the relati...

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Problems solved by technology

[0002] In the visible and infrared fields, Gaussian beams are often used for collimation and cutting operations. At the same time, Gaussian beams are expected to have the characteristics of small diffraction angle and small beam radius. However, in practical applications, the beam divergence angle and diffraction angle show an anti-correlation relationship. Therefore, people have been looking for a way to make the laser beam not diffracted or not diffracted within a certain transmission distance. In 1987, American scientists first introduced the concept of "non-diffraction beam" and obtained it in theory and experiments. Verification, it has been proved theoretically that the non-diffraction beam in the absolute sense is impossible to exist, but in the relative sense, the light beam with limited energy can still realize the non-diffraction transmission over a limited distance, so the previous research work focused on how to Simple and effective generation of Bessel beams, how can Bessel beams achieve no diffraction at longer distances, and whether the conversion efficiency of Bessel beams can be improved

[0003] In the millimeter wave band, the method of generating Bessel beams is similar to the visible light and infrared bands, but the difficulty is different. The beam alignment in the millimeter wave band is not as easy as infrared and visible light. Many methods cannot be used, such as inversion The reason for the telescope method is that the beam spot of the Bessel beam produced by this method is too large and the energy concentration is not enough. Therefore, considering its collimation, a metamaterial lens antenna is often used, but the processing of the metamaterial lens antenna is difficult and the accuracy is relatively high. The requirements are quite high and the frequency band used is narrow, which has always limited its use

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