A common-phase flexible slot-type radiating surface antenna

Abstract

The present invention discloses a common phase-centroid flexible slot-type radiating surface antenna, comprising a radiating layer (1), a metal floor (2), and a dielectric layer (3) arranged between the radiating layer (1) and the metal floor (2); the radiating layer (1) comprises a plurality of unit radiating surfaces (4), each of which is provided with four bow-tie-shaped slots (5); each of the bow-tie-shaped slots is composed of two strip-shaped slots, and the two strip-shaped slots intersect at the exact center of the unit radiating surface (4); a feeding point (6) is arranged between the two strip-shaped slots of each bow-tie-shaped slot. The present invention has an overlapping and fixed phase center, and is easy to perform polarization synthesis.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a common-core flexible slot-type radiating surface antenna. Background Art

[0002] At present, electronic systems are becoming more and more low-frequency, and the requirements in the low frequency band (300M~2GHz) are getting higher and higher, and the demand is urgent. The existing wide-band antennas mainly include: planar spiral antenna, tapered slot antenna, logarithmic periodic antenna, conical spiral antenna, etc. Planar spiral antenna is a classic wide-band antenna with a working bandwidth of more than 9:1, but the problem is that the unit size is large, the reflection cavity needs to be added to form unidirectional radiation, the cross-sectional size is high, and it is limited by the half-wavelength array condition, so it is difficult to form a broadband array to meet the needs of multi-functional array comprehensive applications. The tapered slot antenna is also a classic wide-band antenna. Due to its compact antenna form, it can form a broadband comprehensive array to meet the needs of multi-functional applications such as reconnaissance and interference, but the cross-sectional height of the tapered slot antenna is generally 1 / 4 of the low-frequency wavelength. After miniaturization design, it can be reduced to 1 / 6 of the low-frequency wavelength, and conventional size antennas can usually reach a bandwidth of about 3:1. Further widening will show obvious frequency-varying characteristics, resulting in a large performance difference between high and low frequency bands. Although log-periodic antennas and conical spiral antennas can achieve wider frequency bands, their profile heights are determined by the frequency band width and are not easy to reduce. In addition, the unit size is large, making it difficult to form a broadband array to meet the needs of comprehensive applications of multi-functional arrays.

[0003] In the P~L bands, existing antenna solutions usually exhibit several characteristics: 1. Large thickness; 2. Large unit size; 3. Difficult to form dual polarization; 4. Poor polarization isolation. Summary of the invention

[0004] The object of the present invention is to overcome the deficiencies of the prior art and to provide a common phase-centre flexible slot-type radiating surface antenna, which has overlapping and fixed phase centers and is easy to perform polarization synthesis.

[0005] The object of the present invention is achieved through the following technical solutions: A common phase-centroid flexible slot-type radiating surface antenna, comprising a radiating layer, a metal floor, and a dielectric layer arranged between the radiating layer and the metal floor;

[0006] The radiation layer includes a plurality of unit radiation surfaces, each of which is provided with four bowtie-shaped slots; each bowtie-shaped slot is composed of two strip-shaped gaps, and the two strip-shaped gaps intersect at the exact center of the unit radiation surface; a feeding point is provided between the two strip-shaped gaps of each bowtie-shaped slot.

[0007] Preferably, each of the unit radiating surfaces is a rectangular metal surface; the two diagonals of the unit radiating surface divide the entire unit radiating surface into four parts: upper, lower, left and right; each part is provided with a bowtie-shaped slot, and a triangular radiating sheet is formed between the two strip gaps of each bowtie-shaped slot; the feeding point is arranged at the intersection of the two strip gaps of the bowtie-shaped slot, and contacts the vertex of the triangular radiating sheet between the two strip gaps; the bowtie-shaped slots in the upper and lower parts of the unit radiating surface are symmetrical to each other; the bowtie-shaped slots in the left and right parts of the unit radiating surface are symmetrical to each other.

[0008] The beneficial effects of the present invention are as follows: the present invention forms magnetic flux radiation through slot-type radiation, reduces the requirements on the antenna profile, is beneficial to reducing the antenna profile height (especially for frequencies below the L band, the antenna profile height is greatly reduced, which is convenient for installation), and is easy to conform; slot radiation is formed by a gradient-type oscillator, which has the effect of expanding the bandwidth and can achieve a wider bandwidth; the co-phase core feeding that crosses the unit geometric center can reduce the effect of the cross-polarization current component and has better cross-polarization isolation; it has overlapping and fixed phase centers, dual polarization, and is easy to perform polarization synthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the principle of the present invention;

[0010] Figure 2 This is a schematic diagram of the array of the radiation layer in the embodiment;

[0011] Figure 3 It is a schematic diagram of the magnetic flux radiation principle;

[0012] Figure 4 It is a structural schematic diagram of the unit radiation surface;

[0013] Figure 5 It is the feeding schematic diagram of the unit radiation surface;

[0014] Figure 6 Schematic diagram of the radiation surface current distribution of the unit radiation surface;

[0015] Figure 7 is the cross-polarization simulation pattern (F1);

[0016] Figure 8 is the cross-polarization simulation pattern (F2);

[0017] Fig. 9 is a schematic diagram of power feeding in the embodiment;

[0018] Fig.10 is a schematic diagram of the appearance of a conformal antenna array in an embodiment;

[0019] Fig.11Schematic diagram of standing wave simulation results in the embodiment;

[0020] In the figure, 1-radiation layer, 2-metal floor, 3-dielectric layer, 4-unit radiation surface, 5-bow tie-shaped slot, 6-feeding point, 7-triangular radiation plate. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0022] like Figure 1 As shown, a common-phase-centroid flexible slot-type radiating surface antenna comprises a radiating layer 1, a metal floor 2, and a dielectric layer 3 arranged between the radiating layer 1 and the metal floor 2;

[0023] The radiation layer 1 includes a plurality of unit radiation surfaces 4, each of which is provided with four bowtie-shaped slots; each bowtie-shaped slot is composed of two strip-shaped gaps, and the two strip-shaped gaps intersect at the exact center of the unit radiation surface 4; a feeding point is provided between the two strip-shaped gaps of each bowtie-shaped slot.

[0024] In the embodiment of the present application, the dielectric layer is made of a flexible dielectric material, which can adapt to the curved surface shape to achieve conformal installation and is easy to conform;

[0025] In the embodiment of the present application, the unit radiation surfaces 4 on the radiation layer 1 can be arranged in an array as required, for example, in an x×y manner (such as 2×3, 2×4, 3×3), such as Figure 2 As shown, it is a schematic diagram of an array of 3×3 unit radiation surfaces 4; adjacent unit radiation surfaces are separated by gaps.

[0026] The present invention forms magnetic flux radiation through slot-type radiation, reduces the requirements for antenna profile, is conducive to reducing the antenna profile height (especially for frequencies below the L band, greatly reducing the antenna profile height, which is convenient for installation), and is easy to conform. The principle of magnetic flux radiation is as follows Figure 3 As shown. According to the mirror principle, in the presence of a metal reflective floor (equivalent to the PEC boundary), the magnetic current source forms a co-directional mirror source compared to the current source, which can form radiation enhancement at a low profile (h is much smaller than a quarter wavelength). However, most antennas are current-type radiation. In the presence of a metal reflective floor (equivalent to the PEC boundary), a co-directional mirror source is formed, and the thickness must be about a quarter of a wavelength to form effective superimposed radiation. This is the principle that slot magnetic current radiation can reduce the profile. Therefore, the antenna unit of the present application has a low profile and a metal floor. In addition, the dielectric layer mentioned above uses a flexible dielectric material, which is convenient for installation and conformal design with the platform.

[0027] like Figure 4As shown, in the embodiment of the present application, each of the unit radiation surfaces 4 is a rectangular metal surface; the two diagonal lines of the unit radiation surface 4 divide the entire unit radiation surface 4 into four parts: upper, lower, left, and right; each part is provided with a bowtie-shaped slot, and a triangular radiation sheet 7 is formed between the two strip-shaped slots of each bowtie-shaped slot; the feeding point is provided at the intersection of the two strip-shaped slots of the bowtie-shaped slot, and contacts the vertex of the triangular radiation sheet between the two strip-shaped slots; the bowtie-shaped slots in the upper and lower parts of the unit radiation surface 4 are symmetrical to each other. The bowtie-shaped slots in the left and right parts of the unit radiation surface 4 are symmetrical to each other.

[0028] The slot radiation formed by the gradient oscillator has the effect of expanding the bandwidth. Specifically, if the magnetic flux radiation is a resonant structure, its bandwidth is small. The present invention is based on the above magnetic flux type low profile design. In terms of structure, the radiation slot structure is formed by the bow tie type oscillator, and a gradient impedance structure is formed in the spatial impedance, so that a wider working bandwidth can be achieved. Figure 4 As shown, the triangular radiation sheet 7 and the bow-tie-shaped slot 5 are both gradually changing structures from small to large, and their mechanism is similar to that of a bow-tie-shaped radiation oscillator, which can theoretically achieve a wider working bandwidth.

[0029] In an embodiment of the present application, four bowtie-shaped slots on a metal surface are used to form dual-polarization radiation, wherein the upper and lower radiation slots (bowtie-shaped slots) form vertical polarization, and the left and right slots (bowtie-shaped slots) form horizontal polarization, thereby forming orthogonal polarization; a parasitic oscillator is formed in the metal patch portion between the two bowtie-shaped slots in the vertical direction and the two bowtie-shaped slots in the horizontal direction, thereby forming slot radiation.

[0030] The antenna provided by the present invention adopts absorption impedance loading around to reduce the size of the antenna and improve the coupling isolation between antennas. The loading method can include a variety of methods, which are determined according to different antenna processing methods, such as independent concentrated resistance loading, surface resistance loading based on printed film technology, and distributed loading based on absorbing materials, etc., which can be optimized and selected according to the specific structure of the antenna. For example, the structure of the present application adopts resistance loading, that is, loading resistance on the gap between two adjacent co-polarized vibrators, that is, in the process of unit radiation surface array, for any unit radiation surface, if it has adjacent unit radiation surfaces in any direction of the upper, lower, left, and right, then: in two adjacent unit radiation surfaces, there is a triangular radiation plate in the first unit radiation surface that is directly opposite to a triangular radiation plate in the second unit radiation surface, and the two facing triangular radiation plates are connected by loading resistance.

[0031] The antenna radiating surface provided by the present invention uses two sets of double wires for feeding, and the feeding point position is as follows: Figure 5As shown, feed point 1 and feed point 4 form a group, and feed point 2 and feed point 3 form a group.

[0032] The antenna radiating surface provided by the present invention has the same phase center for horizontal and vertical polarization, which is convenient for polarization synthesis. The phase center of broadband antennas such as gradient slot antennas, log-periodic antennas, and conical spiral antennas varies with frequency, while the phase centers of the horizontal polarization and vertical polarization of the antenna radiating surface structure in the present application are at the same point and do not vary with frequency, which is conducive to polarization synthesis. And because the antenna has a very low profile, it is easy to be conformally installed on surfaces such as the body. Combined with flexible circuit design technology, it can be designed as a curved conformal antenna according to the platform conditions, which is easy to install and save space. Specifically: It has the following characteristics:

[0033] Wide bandwidth: The antenna provided by the present invention utilizes four bowtie-shaped slots on the metal surface to form dual polarization for radiation. The bowtie-shaped slotted oscillator has a gradient impedance characteristic, and impedance matching is achieved by end impedance loading, so it has an extremely wide working bandwidth;

[0034] Common phase core dual polarization: The present invention adopts a dual polarization bowtie-type dipole feeding structure with orthogonal combination. The phase center of a single bowtie-type dipole is located at the geometric center. This form of orthogonal configuration can ensure that the phase centers of the horizontal and vertical polarization dipoles coincide, which is convenient for polarization synthesis.

[0035] High polarization isolation: The radiating surface structure adopted by the present invention has strict symmetry in both horizontal and vertical directions, which can cancel the cross-polarization components brought by the asymmetric structure (the symmetrical cross-polarization components cancel each other, such as Figure 6 As shown), it has excellent high polarization isolation characteristics;

[0036] The present invention aims at the limitations of existing antenna installation space being limited and high profile, and provides a broadband dual-polarization low-profile curved surface conformal antenna array based on slot radiation. The present invention mainly aims at the situation where broadband dual-polarization application requirements and installation space are limited.

[0037] The broadband low-profile antenna array provided by the present invention can operate at 0.4~2GHz, but the height is only 10mm, which is about 0.013 wavelengths of 0.4GHz; the height of the traditional L-band antenna needs to reach 1 / 4 wavelength of the low-frequency end, which is about 180mm. Therefore, the profile of the antenna array provided by the present invention is about 1 / 18 of the profile of the traditional antenna. Therefore, the low-profile antenna array provided by the present invention is very advantageous when the installation space is limited;

[0038] The dual-polarized antenna array provided by the present invention has extremely low cross-polarization. For a planar array, the cross-polarization can be -20dB~-30dB in a wide bandwidth and wide angle range. The simulated directional pattern is shown in Figure 7~Figure 8 .

[0039] The two polarizations of the antenna are fed at the center of the antenna, and the phase centers of the two polarizations are at the geometric center of the antenna unit radiation surface, which is conducive to polarization synthesis.

[0040] This embodiment is a slot radiation low profile dual polarization conformal antenna operating in the P / L band. The antenna operating frequency band is designed according to 0.4GHz~2GHz, and is conformally mounted on a wing-shaped curved structure through a flexible printed circuit board.

[0041] like Fig. 9 As shown, the antenna is an array structure, which consists of a flexible printed circuit board radiation surface, a filling dielectric layer, a feeding structure, a coaxial connector and a mounting cavity.

[0042] The array elements use orthogonally polarized slot-type radiating units with an array spacing of 66mm, which can meet the requirements of grating-free scanning in the range of 0.4GHz to 2GHz. The azimuth direction is composed of 18 elements, and the working unit is 16 elements, of which the two elements on the left and right are virtual elements to balance the amplitude and phase consistency of the units in the array. The elevation structure is a 3-element structure, and the upper and lower rows of units are virtual elements that balance the amplitude and phase, and at the same time play a role in improving cross-polarization isolation. The total length of the antenna array is 1200mm and the total height is 120mm.

[0043] The radiating surface is printed with 0.127mm thick Duroid5880 flexible circuit board, and the filling dielectric layer is made of high-density PMI foam material, which is precisely formed by CNC machining. The radiating surface is bonded to the PMI foam material. The feeding structure uses a broadband balanced balun to achieve orthogonal feeding in a wide frequency band. The schematic diagram of the antenna structure is shown in Fig.10 .

[0044] In this embodiment, the radiation units are loaded by an absorbent surface resistor, and the surface resistor square resistance is 50Ω / □. The surface resistor is made by a microwave printed plate process compatible with the radiation surface printed plate.

[0045] ±60° scanning can be achieved by using 16 elements. The simulated voltage standing wave is as follows: Fig.11 shown.

[0046] The above is a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not depart from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A common-phase-core flexible slot-type radiating surface antenna, characterized in that: It comprises a radiation layer (1), a metal floor (2), and a dielectric layer (3) arranged between the radiation layer (1) and the metal floor (2); The radiation layer (1) comprises a plurality of unit radiation surfaces (4), each of the unit radiation surfaces (4) being provided with four bowtie-shaped slots (5); each bowtie-shaped slot (5) being composed of two strip-shaped slots, and the two strip-shaped slots intersect at the exact center of the unit radiation surface (4); and a feeding point (6) being provided between the two strip-shaped slots of each bowtie-shaped slot; The two diagonal lines of the unit radiation surface (4) divide the entire unit radiation surface (4) into four parts: upper, lower, left and right. Each part is provided with a bow tie-shaped slot, and a triangular radiation sheet (7) is formed between two strip-shaped gaps of each bow tie-shaped slot. The feeding point is arranged at the intersection of two strip-shaped slots of the bowtie-shaped slot and contacts the vertex of the triangular radiation sheet between the two strip-shaped slots; The two upper and lower bow-tie-shaped slots (5) form vertical polarization, and the two left and right bow-tie-shaped slots (5) form horizontal polarization, thereby forming orthogonal polarization; A parasitic oscillator is formed in the metal patch portion between the two bowtie-shaped slots (5) in the vertical direction and the two bowtie-shaped slots (5) in the horizontal direction, thereby forming slot radiation.

2. The common-phase-core flexible slot-type radiating surface antenna according to claim 1, characterized in that: Each of the unit radiation surfaces (4) is a rectangular metal surface.

3. The common-phase-core flexible slot-type radiating surface antenna according to claim 1, characterized in that: The bowtie-shaped grooves in the upper and lower parts of the unit radiation surface (4) are symmetrical to each other.

4. The common-phase-core flexible slot-type radiating surface antenna according to claim 1, characterized in that: The bowtie-shaped grooves in the left and right parts of the unit radiation surface (4) are symmetrical to each other.

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