JP7025596B2 - Double polarization dipole antenna for wide-angle scanning - Google Patents

Description

The present invention relates to the field of antenna technology, specifically to a dual polarization dipole antenna for wide-angle scanning.

Antennas are one of the most important components in radio broadcasting, radio communication and radio detection systems, and their structure and characteristics greatly influence the performance of the entire system. Phased array antennas have become an important development direction for modern antennas due to their excellent beam scanning and beamforming capabilities. Radar, communications and other systems often require phased array antennas with wide operating frequency bands, large scan angles, and low return loss. Some special purpose antennas need to be highly environmentally adaptable in order to adapt to harsh working conditions.

The dual polarization antenna consists of two antennas whose polarizations are orthogonal to each other and is widely used in modern radars and communication systems. Commonly used dual polarization antennas include microstrip antennas, dipole antennas, Vivaldi antennas and the like. A cross-section type double-polarized antenna consisting of two dipole antennas orthogonal to each other has advantages such as wide bandwidth, low processing difficulty, and high reliability. Therefore, a double-polarized phased array is used. It is often used as an array unit.

In a conventional dual polarization dipole antenna, when scanning at a large angle, the impedance changes abruptly, causing impedance mismatch and causing serious return loss. When scanning up to ± 60 °, the return loss of the antenna unit often reaches -6 dB. On the other hand, in some special applications, antennas often face complex work environments such as heavy rains and snow and extreme weather. Since the conventional double-polarized dipole antenna has a wide cross-sectional area, snow easily accumulates, which greatly affects the operating time of the antenna.

The problem to be solved by the present invention is to provide a dual polarization dipole antenna for wide-angle scanning in order to realize wide-angle scanning with low return loss and to meet work demand in extreme weather such as heavy rain and heavy snowfall. That is.

The present invention solves the above problem by the following technical solutions. According to the present invention, it is a double polarization dipole antenna for wide-angle scanning including a first metal arm, an antenna support, a second metal arm, and a feeding balun, and the first metal arm is located at the top of the antenna. The purpose is to improve the impedance fluctuation when the antenna scans at a large angle, and the power supply balun is located at the bottom of the antenna and is used to convert the unbalanced power supply input from the coaxial cable into a balanced power supply. The antenna support is located between the feeding balun and the first metal arm to support the first metal arm, and the second metal arm is provided on the feeding balun. The first metal arm is a vertical cross blade-shaped metal arm, the second metal arm is a vertical blade-shaped metal dipole arm, and the first metal arm and the second metal arm are any of them. Also includes a horizontal portion and a bent portion, and the horizontal portion and the bent portion are integrally molded to provide a double polarization dipole antenna for wide-angle scanning.
Since the metal arm having the above shape has a small cross-sectional area and is resistant to rain and snow, it has a strong resistance to wind, rain and snow of the entire antenna, and can be adapted to extreme weather and complicated work environments. By adopting the vertical cross blade-shaped metal arm, the impedance fluctuation when the antenna scans at a large angle is improved.

Preferably, there are two sets of the second metal arms, for a total of four, and the two sets of the second metal arms are symmetrically distributed.

Preferably, the antenna has a structurally symmetrical structure, and its two polarization directions are orthogonal to each other.

Preferably, there are two sets of the feeding baluns, and the two sets of the feeding baluns are orthogonal to each other, so that it is convenient to feed the two sets of dipole arms whose polarization directions are orthogonal to each other.

Preferably, the feeding balun of each set includes a coaxial cable, a grounded metal column, a metal bridge and a medium base, the metal bridge is provided on the medium base, and the medium base is on the upper end of the coaxial cable and the grounded metal column. The metal bridge provided is for connecting a coaxial cable and a grounding metal column.

Preferably, the feeding balun of each set further comprises a plurality of medium struts, the coaxial cable comprises a coaxial inner conductor and a coaxial outer conductor, the coaxial inner conductor being located inside the coaxial outer conductor and the plurality. The medium columns are provided outside the coaxial internal conductors, and the coaxial internal conductors are fixed by the medium columns.

Preferably, the coaxial outer conductor and the ground metal column form a parallel two-wire structure, and the two sets of the second metal arms are fixed to the coaxial outer conductor and the ground metal column by welding, respectively, and power is supplied by the parallel two-wire structure. do.

Preferably, the bent portion is bent downward, and the angle of the second metal arm at the bent portion coincides with that of the first metal arm. By bending downward, it can act as a guide for rain and snow.

The present invention has the following advantages over the prior art.
According to this double polarization dipole antenna for wide-angle scanning, the impedance matching when the antenna scans at a large angle is greatly improved, the wide-angle scanning performance of the antenna is effectively improved, and within the range of 208 MHz-260 MHz. Wide angle scanning of ± 60 ° is achieved, and the voltage standing wave ratio during operation is less than 1.5, which is better than the voltage standing wave ratio when a conventional dipole antenna scans at a wide angle of ± 60 °. It is suppressed. Also, the antenna has good cross polarization performance and the cross polarization level is less than -25 dB. Finally, the metal dipole arm and the metal arm at the top both adopt a vertical blade-like bending structure with an extremely small cross-sectional area, which makes it difficult for snow and rain to collect, and for antenna performance and life such as snow and rain. The impact is reduced, especially in bad weather conditions such as heavy rain and snow.

It is a schematic diagram of the whole structure of this invention. It is a local exploded view of this invention. It is a side sectional view of FIG. 1 of this invention. It is a top view of FIG. 1 of the present invention. It is a schematic diagram of the voltage standing wave ratio when an antenna scans. It is a cross-polarization direction diagram on the 230MHz frequency point of the antenna.

1: 1st metal arm, 2: Antenna strut, 3: 2nd metal arm, 4: Feeding balun, 41: Coaxial inner conductor, 42: Coaxial outer conductor, 43: Ground metal column, 44: Medium strut, 45: Metal Screw, 46: metal bridge, 47: medium base.

Hereinafter, embodiments of the present invention will be described in detail. This embodiment is carried out on the premise of the technical solution of the present invention and shows a detailed embodiment and a specific operation process, but the scope of protection of the present invention is not limited to the following examples.

As shown in FIG. 1, in this embodiment, it is a double polarization dipole antenna for wide-angle scanning including a first metal arm 1, an antenna support 2, a second metal arm 3, and a feeding balun 4.
The first metal arm 1 is located at the top of the antenna and improves the impedance fluctuation when the antenna scans at a large angle.
The power supply balun 4 is located at the bottom of the antenna and converts the unbalanced power supply input from the coaxial cable into a balanced power supply.
The antenna support 2 is located between the feeding balun 4 and the first metal arm 1 and supports the first metal arm 1.
The second metal arm 3 is located at the upper end of the outside of the feeding balun 4, and is fed by the feeding balun 4.
The first metal arm 1 is a vertical cross blade-shaped metal arm, the first metal arm 1 is a parasitic element and does not form a palace, and the second metal arm 3 is a vertical blade-shaped metal dipole arm and a first metal arm. The first and second metal arms 3 both include a horizontal portion and a bent portion, the horizontal portion and the bent portion have an integrally molded structure, and the bent portion is provided with a double polarization dipole antenna for wide-angle scanning that bends downward. ..
The angle of the second metal arm at the bending point coincides with that of the first metal arm, and by bending downward, it is possible to play an action of guiding rain or snow. Since the metal arm having the above shape has a small cross-sectional area and is resistant to rain and snow, it has a strong resistance to wind, rain and snow of the entire antenna, and can be adapted to extreme weather and complicated work environments. By adopting the vertical cross blade-shaped metal arm, the impedance fluctuation when the antenna scans at a large angle is improved.

The operating frequency of the antenna is 208 MHz to 260 MHz, and the polarization method is horizontal polarization and vertical polarization. The antenna units are arranged in a triangular grid. The distance between the antenna units in the horizontally polarized direction is 740 mm, and the distance between the antenna units in the vertically polarized direction is 640 mm. When the antennas are actually arranged in a triangular grid, the number of horizontal and vertical units thereof can be expanded as needed in practice. Similarly, the antennas can be arranged in a rectangular grid arrangement, ring arrangement or other type of arrangement as needed in practice.

The first metal arm 1 includes two vertical blade-shaped metal arms orthogonal to each other, and the vertical blade-shaped metal arm has a horizontal length of 370 mm, a vertical height of 106 mm, and a thickness of 3 mm, and an antenna. It is provided at the upper end of the support column 2. The metal arm 1 and the antenna support 2 are fixed by screws or the like. The antenna support 2 uses a polytetrafluoroethylene material having a dielectric constant Dk = 2.1. The antenna support 2 has a maximum diameter of 95 mm and a height of 45 mm, and is provided on the feeding balun 4. The antenna support 2 and the power supply balun 4 are fixed by a method such as a screw.

As shown in FIG. 2-4, there are two sets of feeding baluns 4, and the two sets of feeding baluns 4 are orthogonal to each other. This makes it convenient to supply power to each of the two sets of dipole arms whose polarization directions are orthogonal to each other. The feeding balun 4 of each set includes a coaxial cable, a grounded metal column 43, a metal bridge 46 and a medium base 47. The metal bridge 46 is provided on the medium base 47 and is fixed by four metal screws 45, respectively. The medium base 47 is provided at the upper end of the coaxial cable and the ground metal column 43. The metal bridge 46 connects the coaxial cable and the grounding metal pillar 43. Each set of feed baluns 4 further includes a plurality of medium struts 44. The coaxial cable includes a coaxial inner conductor 41 and a coaxial outer conductor 42. The coaxial inner conductor 41 is located inside the coaxial outer conductor 42, and the plurality of medium columns 44 are provided outside the coaxial inner conductor 41, respectively. The coaxial outer conductor 42 and the grounding metal column 43 form a parallel two-wire structure. The two sets of the second metal arms 3 are welded and fixed to the coaxial outer conductor 42 and the ground metal column 43, respectively, and are fed by a parallel two-wire structure.

The coaxial outer conductor 42 and the ground metal pillar 43 are symmetrical in position, have the same size, have a diameter (outer diameter of the coaxial outer conductor 42) of 28.08 mm, and have a height of 423.7 mm. Is 25.86 mm. The coaxial outer conductor 42 is a hollow metal cylinder having an inner diameter of 24 mm. The coaxial inner conductor 41 is located at the center of the coaxial outer conductor 42, has the same height as the coaxial outer conductor 42, and is fixed by a medium column 44 made of a polytetrafluoroethylene material. The diameter of the coaxial internal conductor 41 is determined by the need for impedance conversion and whether the internal conductor penetrates the medium column 44, with a maximum diameter of 10 mm and a minimum diameter of 4.774 mm, and the bottom of the coaxial internal conductor 41 is , Connected to a coaxial RF connector to supply power.

The total length of the metal bridge 46 is 64 mm and the width is 10 mm. The minimum distance between the metal bridge 46, the coaxial outer conductor 42 and the grounded metal column 43 is 9 mm. Both arms of the vertical blade-shaped metal dipole arm are welded to the outer apex of the coaxial outer conductor 42 and the ground metal column 43, respectively, and are fed by the coaxial outer conductor 42 and the coaxial inner conductor 41-metal bridge 46-ground metal column 43 structure in order. Will be done. Each dipole arm has a horizontal length of 190 mm, a vertical height of 238 mm, and a thickness of 3 mm.

The antenna support 2, the medium support 44, and the medium base 47 are made of a polytetrafluoroethylene material, and the other structures are made of a metal material. The vertical cross bladed metal arm greatly improves impedance matching as the antenna scans. The addition of the cross-blade metal arm essentially changes the resonance point and impedance when scanning at a large angle by introducing capacitance and inductance into the equivalent circuit of the antenna, and the structure of the blade-shaped metal arm. Is applied in extreme weather environments because it provides the ability to resist relatively strong winds and snow.

As shown in FIG. 5, when the horizontal and vertical polarizations are operated at E-plane / H-plane ± 60 °, the voltage standing wave ratio in the range of 208 MHz-260 MHz is less than 1.5. Therefore, a wide-angle scanning process with low return loss is realized.

As shown in FIG. 6, the E-plane / H-plane orientation view of the antenna shows no significant deterioration within the bandwidth and the cross-polarization level is less than -25 dB.

From the above, according to the double polarization dipole antenna for wide-angle scanning of this embodiment, the impedance matching when the antenna scans at a large angle is greatly improved, and the wide-angle scanning performance of the antenna is effectively improved. Wide angle scanning of ± 60 ° is achieved within the range of 208MHz-260MHz, the voltage standing wave ratio during operation is less than 1.5, and the voltage constant when a conventional dipole antenna scans at a wide angle of ± 60 °. It is suppressed better than the current wave ratio. Also, the antenna has good cross-polarization performance and the cross-polarization level is less than -25 dB. Finally, the metal dipole arm and the metal arm at the top both adopt a vertical blade-like bending structure with an extremely small cross-sectional area, which makes it difficult for snow and rain to collect, and for antenna performance and life such as snow and rain. The impact is reduced, especially in bad weather conditions such as heavy rain and snow.

The above description merely describes a preferred embodiment of the present invention and does not limit the present invention. Any modifications, equivalent substitutions and improvements made within the scope of the ideas and principles of the invention should be included within the scope of protection of the invention.

Claims (8)

A double-polarized dipole antenna for wide-angle scanning including a first metal arm, an antenna support, a second metal arm, and a feeding balun.
The first metal arm is located at the top of the antenna and is provided at the upper end of the antenna support column to improve impedance fluctuation when the antenna scans at a large angle.
The feeding balun is located at the bottom of the antenna and is for converting the unbalanced feeding input from the coaxial cable into the balanced feeding.
One end of the antenna support is connected to the feeding balun, and the other end is connected to the first metal arm to support the first metal arm.
The second metal arm is provided on the feeding balun and is fed by the feeding balun.
The first metal arm is a vertical cross blade-shaped metal arm, the second metal arm is a vertical blade-shaped metal dipole arm, and both the first metal arm and the second metal arm are horizontal portions and bent portions. A dual polarization dipole antenna for wide-angle scanning, characterized in that the horizontal portion and the bent portion have an integrally molded structure. There are two sets of the second metal arms, for a total of four.
The double polarization dipole antenna for wide-angle scanning according to claim 1, wherein the two sets of the second metal arms have polarization directions orthogonal to each other and are symmetrically distributed. The double-polarized dipole antenna for wide-angle scanning according to claim 1, wherein the antenna has a structurally symmetrical structure, and the two polarization directions thereof are orthogonal to each other. There are two sets of the power supply balun.
The double polarization dipole antenna for wide-angle scanning according to claim 2, wherein the two sets of the feeding baluns feed each other to two sets of metal dipole arms which are orthogonal to each other and whose polarization directions are orthogonal to each other. .. The feeding balun of each set includes coaxial cables, grounded metal columns, metal bridges and medium bases.
The metal bridge is provided on a medium base, the medium base is provided on the upper end of a coaxial cable and a grounded metal column, and the coaxial cable is connected to the grounded metal column by a metal bridge. Item 4. The double-polarized dipole antenna for wide-angle scanning according to Item 4. Each set of said feeding baluns further comprises a plurality of medium struts.
The coaxial cable includes a coaxial inner conductor and a coaxial outer conductor.
The coaxial inner conductor is located inside the coaxial outer conductor, the plurality of the medium struts are provided outside the coaxial inner conductor, respectively, and the coaxial inner conductor is fixed by the medium stanchion. The dual polarization dipole antenna for wide-angle scanning according to claim 5. The coaxial outer conductor and the grounded metal column form a parallel two-wire structure.
The double polarization dipole for wide-angle scanning according to claim 6, wherein the two sets of the second metal arms are fixed to a coaxial outer conductor and a ground metal column, respectively, and are fed by a parallel two-wire structure. antenna. The bent portion bends downward and
The double-polarized dipole antenna for wide-angle scanning according to claim 1, wherein the second metal arm has an angle at a bending point that matches that of the first metal arm.

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