The parabolic reflector is aaxial symmetryQuadric surfacereflector, when the light source is located atfocusThe light emitted by the light source is reflected by the reflector to obtain a parallel beam.Parabolic reflector can be used asXenon lampReflector of.Parabolic antenna reflector is one of the important tools for communication between stars and earth.
Parabolic reflector is an ideal xenon lamp reflector.When the xenon lamp light source is placed at the focal point of the parabolic reflector, most of the reflected beams are parallel to the optical axis, so that the reflected beams with small divergence angle can be obtained after being reflected by the reflector, thus obtaining higher illuminationpower density Therefore, the parabolic reflector is selected as the xenon lamp reflector.For a good reflector, the first thing is to collect as much radiation energy from the light source as possible and project it into the far field.Generally, the ability of the reflector to collect the radiant energy of the light source is related to the containment angle of the light source in the reflector. The larger the containment angle of the reflector, the higher the utilization rate of the light source, and the higher the energy projected to the far field.For parabolic reflector, due to the limitation of depth and focal length of parabolic reflector, the reflector can only reflect the radiation energy concentrated in the containment angle to form an effective radiation beam, and the rest of the radiation energy is emitted directly.The containment angle of the parabolic reflector is related to the focal length, diameter and center hole diameter of the reflector.literature[1]According to the characteristics of parabolic reflector, the relationship between the reflector's focal length, aperture, axial defocus, etc. and the reflector's containment angle is analyzed. At the same time, the influence of axial defocus on the reflector's containment angle and full luminous distance is analyzed. A xenon lamp parabolic reflector with aperture D=140 rnm, center hole diameter d=28mm, and focal length f=15.65mm is designed,The reflector can obtain xenon light beam with divergence angle better than 1 degree. At the same time, according to theParabolic reflectorThe defocusing analysis results show that, in order to increase the inclusion angle of the reflector and improve the utilization of the light source, the light source can be placed in front of the reflector focus, but at the same time, the full luminous distance becomes shorter.Therefore, in practical use, it is necessary to comprehensively consider the defocus position in order to obtain better results.
error analysis
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The actual reflector can not be completely consistent with the theoretical reflector, and there are certain errors.When designing reflectors, it should be specified that reasonable manufacturing error should be used to limit the error within a certain range. If the tolerance is set too small, it will cause heavy structure and manufacturing difficulties;If the tolerance is too large, the electrical performance will deteriorate.Therefore, it is necessary to study the influence of surface error on the reflector performance.Surface roughnessIt is a trace of unevenness with small spacing and peak valley composition formed after part surface processing.The value of surface roughness parameter has a direct impact on the service performance and life of parts.Ideally, the phase center of the feed should be completely coincident with the focus, but in fact there is always some deviation, which is caused by the deformation of the feed bracket and the inaccurate installation of the feed.In the radio frequency target simulation, the tracking error of the seeker is mainly affected by the mechanical movement of the target simulator and the mechanical error of the parabolic reflector (including the surface error and the installation and deformation error of the feed bracket).The mechanical error of parabolic reflector mainly affects the phase.literature[2]The relationship between various errors is analyzed, and the mathematical model of the relationship between mechanical error and phase is established according to the needs of engineering design.
Related patents
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Invention patent[3]A design method of a compact planar parabolic reflector antenna based on metamaterials is disclosed, which includes the following steps: a feed unit with a planar boundary is designed using the principle of transformation electromagnetism;The parabolic reflector with plane structure is used as the reflector of reflector antenna instead of the parabolic reflector with conventional curved surface structure;The plane reflector and feed unit are combined to design a compact plane reflector antenna.The reflective surface of the invention adopts a plane reflector, and its reflective characteristic is equivalent to that of a conventional parabolic reflector;The designed feed unit itself is "transparent" to the ray, that is, it does not block the ray, and the radiation characteristics of the feed placed in it are equivalent to the radiation characteristics of the feed placed far away from the reflector due to the virtual displacement caused by metamaterials;The reflector and feed unit in the reflector antenna are combined to form a compact structure, which avoids the separation of reflector and feed in conventional reflector antenna.
