A composite ultra-wideband director and high-low frequency nested array

Abstract

The present invention discloses a composite ultra-wideband director, which is composed of a director vane and a magnetic current loop. The director vane is placed above the radiation surface of the oscillator, and the magnetic current loop is placed below the radiation surface of the oscillator with its vertical axis coinciding with that of the oscillator. In particular, by designing a double-layer director vane and a spiral magnetic current loop, the above-mentioned composite director realizes ultra-wideband plane wave conversion and gain improvement. The invention combines the plane wave conversion characteristic of the director vane with the characteristic of the magnetic current loop to improve the axial gain, providing a solution for a composite ultra-wideband and high-gain director, so as to better meet the requirements of current 5G ultra-wideband antennas. The present invention also provides a high-low frequency nested array.

Description

Technical Field

[0001] The present invention relates to the field of base station antennas, and particularly to a passive planar wave converter and a high-low frequency nested array for eliminating the distortion of the radiation pattern caused by boundary spurs. Background Art

[0002] The high-low frequency nested array reduces the antenna size and increases the multi-frequency array integration through spatial multiplexing, and is a technical solution widely adopted in the current base station antenna design. A typical high-low frequency nested spatial multiplexing array is as Figure 1 shown: the low-frequency radiation units are arranged in an equally spaced linear array, and the high-frequency radiation units are installed at intervals on the platform above the central axis of the low-frequency radiation units and at the middle positions between adjacent elements of the low-frequency linear array. By multiplexing the space of the low-frequency array with the high-frequency array, the integration of the high-low frequency arrays is achieved without increasing the physical size of the base station antenna.

[0003] Therefore, how to eliminate the interaction between the high-low frequency radiation units has become one of the key problems of the nested array: for the low-frequency radiation units, installing high-frequency radiation units near them, especially on their internal central axis, is equivalent to changing the boundary, which will inevitably affect the standing wave and radiation pattern; for the high-frequency radiation units, whether it is the nested high-frequency oscillator located on the central platform of the low-frequency radiation units or the external high-frequency oscillator located at the middle position between adjacent low-frequency radiation units, they are inevitably affected by the stray waves from the low-frequency radiation units. Especially for the external high-frequency oscillator, since it is in the projection area of the low-frequency radiation units, the low-frequency radiation units cause serious shielding and scattering of the electromagnetic waves radiated by it, and the reflected waves, stray waves and incident waves are superimposed, often resulting in the distortion of the radiation pattern and the decrease of the gain. If effective technical means cannot be found to counter the spurs caused by the above complex electromagnetic boundaries, it will be difficult to implement the miniaturization of the nested array and the antenna! Summary of the Invention

[0004] An object of the present invention is to provide a composite ultra-wideband director capable of countering complex boundary scattering.

[0005] Another object of the present invention is to provide a high-low frequency nested array with the above composite ultra-wideband director.

[0006] To achieve the above object, the present invention adopts the following technical solutions.

[0007] A composite ultra-wideband director, characterized in that it is composed of a director sheet located above the radiation surface of the oscillator and a magnetic current loop located directly below the radiation surface of the oscillator and perpendicular to the central axis of the radiation surface.

[0008] More preferably, the director sheet has a double-layer or multi-layer structure, and the upper director sheet has a larger area than the lower director sheet.

[0009] More preferably, the director is a double-layer metal sheet. The upper metal sheet of the double-layer metal sheet, which is farther from the top of the oscillator, is composed of four metal sheets, and the lower metal sheet, which is closer to the top of the oscillator, is composed of one metal sheet.

[0010] More preferably, the director is a double-layer printed circuit board. The upper printed circuit board and the copper-clad pattern form the upper director, and the lower printed circuit board and the copper-clad pattern form the lower director. The upper and lower printed circuit boards and the copper-clad patterns are exactly the same.

[0011] More preferably, the upper printed circuit board and the lower printed circuit board are connected into a whole through two side plates inserted up and down, and the two side plates are combined together through a mortise and tenon structure.

[0012] More preferably, the magnetic current loop is a closed ring or a spiral structure.

[0013] More preferably, the radius of the spiral structure increases as the spiral ascends.

[0014] A high-low frequency nested array includes: a reflector, a plurality of high-frequency radiation units and a plurality of low-frequency radiation units arranged on the reflector. The high-frequency radiation units are spacedly installed on a platform above the central axis of the low-frequency radiation units and at an intermediate position between two adjacent low-frequency radiation units. It is characterized in that the composite ultra-wideband director as described above is provided on the high-frequency radiation units.

[0015] More preferably, each of the low-frequency radiation units forms a linear array, and the composite ultra-wideband director is provided on the high-frequency radiation unit at an intermediate position between two adjacent low-frequency radiation units.

[0016] More preferably, the operating frequency band of the high-low frequency nested array is 1710 MHz - 2690 MHz.

[0017] A composite ultra-wideband director disclosed by the present invention is composed of a director sheet directly above the oscillator and a magnetic current loop whose vertical axis coincides with that of the oscillator and is placed below the radiation surface of the oscillator, and has the function of counteracting complex boundary scattering. Its working principle is as follows: The director sheet above the radiation surface and the magnetic current loop below the radiation surface together form a plane wave converter, which converts the spherical wave generated by the oscillator radiation into a plane wave with the beam converging upward, thereby reducing the distortion of the radiation pattern and the decrease in gain of the high-frequency oscillator caused by the low-frequency oscillator and boundary stray. In the above plane wave conversion process, the director sheet and the magnetic current loop have different functions: On the one hand, the electromagnetic wave generated by the oscillator radiation induces a current on the director sheet directly above. The electromagnetic wave generated by the radiation of the above current is superimposed on the incident wave to change the phase distribution of the electromagnetic field. By optimizing the shape, size, and height (the vertical distance from the high-frequency radiation surface) of the director sheet, the spherical wave generated by the oscillator radiation can be converted into a plane wave with the wave vector perpendicular to the radiation surface of the oscillator; on the other hand, by optimizing the size and height of the magnetic current loop, the scattering field generated by the magnetic current loop below the vertical axis of the oscillator has an enhancing effect on the electric field directly above, making the radiation field of the oscillator focus upward and the beam width narrower, thereby reducing the influence of the boundary and low-frequency oscillator occlusion and stray on the high-frequency radiation field.

[0018] Compared with the existing director technology, the composite ultra-wideband director of the present invention has the following characteristics:

[0019] 1) Combining the director sheet and the magnetic current loop makes the plane wave conversion efficiency higher, the radiation beam more convergent, and the effect of counteracting boundary stray excellent, especially suitable for directing high-frequency oscillators in high-low frequency nested arrays.

[0020] 2) Adopting a double-layer director sheet and a spiral magnetic current loop enables a larger bandwidth and better meets the requirements of 5G ultra-wideband antennas.

[0021] 3) The process is simple. Whether it is the director sheet or the magnetic current loop, only simple sheet metal and stamping processes are required for mass production, and the cost advantage is obvious. Description of the Drawings

[0022] Figure 1 The figure shows a schematic diagram of an existing high-low frequency nested array.

[0023] [[ID= / / ID=21]] Figure 2 The figure shows a schematic diagram of the structure of the composite ultra-wideband director of the present invention.

[0024] Figure 3 The figure shows another schematic diagram of the structure of the composite ultra-wideband director of the present invention.

[0025] Figure 4 The figure shows a schematic diagram of the application of the composite high-frequency director of the present invention in a high-low frequency nested array.

[0026] Figure 5 The following shows the test results of the radiation pattern of an external high-frequency oscillator without a director.

[0027] Figure 6 The following shows the test results of the radiation pattern of an external high-frequency oscillator after using a director.

[0028] Description of the reference numerals:

[0029] 1: High-frequency oscillator; 2: Director plate; 3: Magnetic current loop; 4: Printed circuit board. Detailed implementation manners

[0030] In the description of the present invention, it should be noted that for orientation terms, such as the terms "center", "transverse", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the orientation and position relationships indicated are based on the orientation or position relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of the present invention.

[0031] In the present invention, unless otherwise clearly specified and defined, for the terms "assembled", "connected", and "coupled", they should be understood in a broad sense. For example, they can be fixedly connected, detachably connected, or integrally connected; they can also be mechanically connected; they can be directly connected, or connected through an intermediate medium, and can be internally connected and communicated between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0032] In the invention, unless otherwise specified and defined, the first feature being "above" or "below" the second feature may include direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "below", and "on top of" the second feature includes that the first feature is directly above or obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "above", "below", and "beneath" the second feature includes that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0033] The following further describes the detailed implementation manners of the present invention in conjunction with the drawings of the specification, making the technical solutions and their beneficial effects of the present invention clearer and more definite. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention, rather than being construed as limiting the present invention.

[0034] Additional aspects and advantages of the present invention will become apparent in the following description section, or will be learned through the practice of the present invention.

[0035] Figure 1 is one of the main application scenarios of the composite ultra-wideband director of the present invention - a schematic diagram of a high-low frequency nested array. In this array, high-frequency radiation units are installed at intervals on the platform above the central axis of the low-frequency radiation unit and at the middle positions between adjacent elements of the low-frequency linear array. By multiplexing the space of the low-frequency array for the high-frequency array, the integration of the high-low frequency arrays is achieved without increasing the physical size of the base station antenna. As Figure 1 shown, for the convenience of explanation, the high-frequency radiation units located on the platform above the central axis of the low-frequency radiation unit are called nested high-frequency oscillators, and the high-frequency radiation units located at the middle positions between adjacent elements of the low-frequency linear array are called external high-frequency oscillators. A prominent problem with the above array configuration is that the radiated electromagnetic waves of the external high-frequency oscillators are severely distorted in the radiation pattern and the gain is significantly reduced due to the occlusion and scattering by the low-frequency oscillators on both sides. Without changing the array configuration and the internal space of the antenna, one of the common methods to eliminate the distortion of the radiation pattern of the external high-frequency oscillators and improve the gain is to change the spatial phase distribution of the radiation electromagnetic field through a director, so as to convert the divergent spherical wave into a plane wave converging towards the normal direction of the radiation surface, thereby reducing the influence of the low-frequency oscillators and boundary strays on the high-frequency radiation pattern. However, the publicly available directors often have the following limitations: 1) The bandwidth is not enough, and it can only solve narrowband problems, but cannot solve ultra-wideband problems; 2) Although it can eliminate the distortion of the radiation pattern to a certain extent, it will cause the gain to decrease. The composite director of the present invention aims to break through the above limitations and provide a solution for a composite ultra-wideband and high-gain director.

[0036] Figure 2 is a schematic diagram of the composite ultra-wideband director of the present invention and its application in a high-low frequency nested array. The composite high-frequency director of the present invention is composed of a director sheet 2 located above the high-frequency oscillator 1 and a magnetic current loop 3 located directly below the high-frequency oscillator 1 and perpendicular to the central axis of the radiation surface. The director sheet 2 is a plane wave converter that changes the spatial phase distribution of the radiated electromagnetic waves and converts the scattered spherical wave into a plane wave converging towards the normal direction of the radiation surface (vertically upwards along the central axis). Since the radiation power is concentrated in the free space directly above the oscillator, the influence of the boundary and the stray waves of the low-frequency radiation units is naturally reduced, and the problem of deformation of the radiation pattern is improved.

[0037] In this embodiment, it is preferable that the director 2 is composed of a double-layer metal sheet. The upper metal sheet in the double-layer metal sheet, which is farther from the top of the high-frequency oscillator, is composed of four metal sheets and has a larger area than the lower metal sheet closer to the top of the high-frequency oscillator, thus having the ability to convert plane waves in a wide frequency band. The magnetic current loop located below the radiation surface of the high-frequency oscillator and coaxial with it is a coil magnetic dipole antenna, and its radiation direction points to the normal direction of the radiation surface of the high-frequency oscillator. By optimizing the height of the magnetic current loop, its scattered field can achieve the optimal enhancement effect on the electromagnetic radiation of the high-frequency oscillator, achieving the purpose of increasing the gain; in addition, after loading the magnetic current loop below the high-frequency oscillator, the half-power angle of the radiation pattern will be narrowed to a certain extent, thus reducing the generation of stray waves to a certain extent.

[0038] Preferably, the magnetic current loop 3 is a spiral magnetic current loop, and as the spiral rises, the radius increases, so as to increase the gain in a wider frequency band.

[0039] As Figure 3 shown, in other embodiments, the director composed of the double-layer metal sheet is replaced by a printed circuit board 4, where the upper printed circuit board and its copper-clad pattern form the upper director, and the lower printed circuit board and its copper-clad pattern form the lower director. The upper and lower printed circuit boards and the copper-clad patterns are exactly the same; the upper and lower printed circuit boards are connected into a whole through mortise and tenon and side plates inserted up and down.

[0040] As a variant embodiment of the above magnetic current loop, the spiral magnetic current loop is replaced by a circular ring; the magnetic current loop is arranged in three or more layers; this is not limited to this embodiment.

[0041] As Figure 4 shown, this is an application example of the composite high-frequency director of the present invention in a high-low frequency nested array. In actual application, the above-mentioned composite high-frequency director is installed on an external high-frequency oscillator. Of course, according to actual needs, the above-mentioned composite high-frequency director is also applied in other antennas and cooperates with oscillators of other frequencies, which is not limited to this embodiment.

[0042] To fully demonstrate the utility of the composite high-frequency director of the present invention, Figure 5 、 Figure 6 respectively give the Figure 1 and Figure 4 comparison of the test results of the radiation patterns of the external high-frequency oscillator shown. From the Figure 5 、 Figure 6 comparison, it can be seen that when the above-mentioned director is not used, the radiation patterns at 1710 MHz and 2690 MHz are severely distorted, and the gain decreases due to the collapse at the top; while after using the composite high-frequency director of the present invention, the above-mentioned radiation pattern distortion is completely eliminated and the gain returns to normal.

[0043] Compared with the existing directors, the composite high-frequency director of the present invention has the following characteristics: 1) The composite director of the present invention is composed of a director plate placed above the high-frequency oscillator and a magnetic current ring placed below the high-frequency oscillator and having its vertical axis coincident therewith; 2) The above-mentioned director plate has a double-layer or multi-layer structure, and the upper director plate has a larger area than the lower director plate; 3) For the purpose of expanding the bandwidth, in addition to using a closed circular ring, the above-mentioned magnetic current ring can also adopt a spiral structure, and the radius of the spiral structure increases as the spiral ascends.

Claims

1. A composite ultra-wideband director, characterized in that, It is applied to the external high-frequency oscillator of a high-low frequency nested array and consists of a director located above the oscillator radiation surface and a magnetic current loop located directly below the oscillator radiation surface and perpendicular to the central axis of the radiation surface; the director is a double-layer metal sheet, where the upper metal sheet of the double-layer metal sheet that is farther from the top of the oscillator is composed of four metal sheets, and the lower metal sheet that is closer to the top of the oscillator is composed of one metal sheet, and the upper director has a larger area than the lower director; the magnetic current loop is a spiral structure, and the radius of the spiral structure increases as it spirals upward.

2. The composite ultra-wideband director according to claim 1, characterized in that, The director is a double-layer printed circuit board, the upper printed circuit board and the copper-clad pattern form the upper director, the lower printed circuit board and the copper-clad pattern form the lower director, and the upper and lower printed circuit boards and the copper-clad patterns are exactly the same.

3. The compound ultra-wideband director according to claim 2, characterized in that, The upper printed circuit board and the lower printed circuit board are connected into a whole through two side plates inserted up and down, and the two side plates are combined together through a mortise and tenon structure.

4. A high-low frequency nested array, comprising: A reflector, a plurality of high-frequency radiation units and a plurality of low-frequency radiation units provided on the reflector, the high-frequency radiation units are spaced apart and installed on a platform above the central axis of the low-frequency radiation units and at an intermediate position between two adjacent low-frequency radiation units; characterized in that a composite ultra-wideband director as described in any one of claims 1-3 is provided on the high-frequency radiation unit at an intermediate position between two adjacent low-frequency radiation units.

5. A high-low frequency nested array according to claim 4, characterized in that, Each of the low-frequency radiation units forms a linear array, and the composite ultra-wideband director is provided on the high-frequency radiation unit at an intermediate position between two adjacent low-frequency radiation units.

6. The high-low frequency nested array according to claim 4, wherein, The operating frequency band of the high-low frequency nested array is 1710 MHz - 2690 MHz.

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