Edge loading structure for improving strong coupling phased array truncation effect

Abstract

The invention discloses an edge loading structure for improving a strong coupling phased array truncation effect, and belongs to the technical field of antenna engineering. The edge loading structure is composed of a dielectric substrate, a semi-butterfly-shaped metal patch and a T-shaped metal patch of a loading resistor. The semi-butterfly-shaped metal patch connected with the array edge unit guides electromagnetic waves to radiate in a traveling wave form at a high frequency band of a working frequency band, and forms a single dipole antenna together with a dipole arm of the array edge unit and a floor at a low frequency band; the T-shaped metal patch of the loading resistor provides a loop to the ground for the semi-butterfly-shaped metal patch and absorbs redundant energy which is not radiated; the invention has the advantages of simple structure, easiness in processing and light weight. In the embodiment of the invention, a 32-unit strong-coupling two-column linear array is designed, and by comparing the active standing-wave ratio during 60-degree scanning of the side emission and the E surface of the array units before and after the structure is loaded, it can be known that the provided structure has a remarkable improvement effect on the truncation effect of the strong-coupling phased array.

Description

Technical Field

[0001] The present invention belongs to the field of antenna engineering technology, and relates to a strongly coupled phased array antenna, and specifically to an edge loading structure for improving the truncation effect of a strongly coupled phased array. This structure can significantly improve the deterioration of array scanning and matching performance caused by the truncation effect of a strongly coupled phased array, and has the characteristics of simple structure, easy processing, and light weight. Background Art

[0002] Phased array antennas have been widely used in radar and communication systems due to their high gain, fast scanning, and beam controllable characteristics. In practical applications, phased arrays are composed of a limited number of array elements. The boundary conditions around the array edge elements and the array center elements are different, which will cause their performance to change, which is the edge truncation effect of the phased array antenna.

[0003] The strongly coupled phased array offsets the inductive effect of the metal floor by introducing a capacitive effect between the array elements, thereby achieving ultra-wideband operation of the antenna array. Due to the strong mutual coupling between the array elements, the edge truncation effect of the strongly coupled phased array is more obvious than that of the traditional phased array. The paper "UWB Low-Profile Tightly Coupled DipoleArray With Integrated Balun and Edge Terminations" discusses two methods for dealing with the truncation effect of the strongly coupled phased array. Method 1: Extend the dipole arm length of the edge antenna unit. This method can achieve a 3-fold operating bandwidth under the condition that the active standing wave ratio in the side-firing direction is less than 3 under the condition of loading a balun; Method 2: Periodically load resistance on the edge. Although this method further optimizes the impedance matching of the array, the low-frequency radiation efficiency of the array is only about 40%. There is no further research and discussion in the paper on the edge truncation effect of the array under large scanning angles. Summary of the invention

[0004] Based on the background technology, the present invention proposes a novel edge loading structure for improving the truncation effect of a strongly coupled phased array, which greatly improves the deterioration of scanning and matching performance caused by the truncation effect of a strongly coupled phased array antenna. The present invention has the characteristics of simple structure, easy processing and light weight.

[0005] The technical solution of the present invention is an edge loading structure for improving the truncation effect of a strongly coupled phased array. The edge loading structure is arranged at the ends of two adjacent rows of an array antenna. Each row of antenna patches in the array antenna is independently provided with a dielectric substrate, and each dielectric substrate is vertically arranged on a metal floor. The edge loading structure comprises: a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a first semi-butterfly metal patch, a second semi-butterfly metal patch, a T-shaped grounded metal patch, a resistor, and a metal floor.

[0006] The first dielectric substrate is integrated with the dielectric substrate of one of the two adjacent rows of the array antenna, and the second dielectric substrate is integrated with the dielectric substrate of the other of the two adjacent rows of the array antenna; the first semi-butterfly metal patch is arranged on the first dielectric substrate, and one end is connected to the coupling patch of the array antenna at the corresponding position; the second semi-butterfly metal patch is arranged on the second dielectric substrate, and one end is connected to the coupling patch of the array antenna at the corresponding position; the metal floor of the edge loading structure is the same as the metal floor of the array antenna; the two sides of the third dielectric substrate are connected to the first dielectric substrate and the second dielectric substrate, and the third dielectric substrate is perpendicular to the metal floor, and the two ends of the "1"-shaped part of the T-shaped grounding metal patch are respectively connected to the other end of the first semi-butterfly metal patch and the second semi-butterfly metal patch; the bottom end of the "1"-shaped part of the T-shaped grounding metal patch is connected to one end of the resistor, and the other end of the resistor is connected to the metal floor.

[0007] Furthermore, the third dielectric substrate is perpendicular to the first dielectric substrate and the second dielectric substrate.

[0008] Furthermore, the first half-butterfly-shaped metal patch and the second half-butterfly-shaped metal patch are right-angled trapezoids, the top side of the right-angled trapezoids is connected to the coupling patch of the array antenna, and the bottom side is connected to the T-shaped grounding metal patch.

[0009] Furthermore, two ends of the “I”-shaped portion of the T-shaped grounding metal patch protrude from the planes of the first dielectric substrate and the second dielectric substrate.

[0010] Furthermore, the waists of the first half-butterfly-shaped metal patch and the second half-butterfly-shaped metal patch close to the metal floor are right-angled waists.

[0011] The semi-butterfly metal patch of the present invention is connected to the coupling patch of the edge antenna unit of the array. In the high frequency band of the antenna working frequency band, the semi-butterfly metal patch is equivalent to an electrically large traveling wave structure, guiding the electromagnetic wave to radiate outward in the form of traveling waves. In the low frequency part of the antenna working frequency band, the metal patch and the edge antenna unit form a single dipole antenna, thereby improving the edge truncation effect of the strong coupling array. The T-shaped grounding metal patch is orthogonally arranged and electrically connected to the semi-butterfly metal patch, providing a current path to the ground for the semi-butterfly metal patch, which can effectively improve the matching of large-angle scanning and low-frequency band array edge units. The resistor is loaded between the T-shaped grounding metal patch and the floor, absorbing part of the excess energy that is not radiated, and improving the matching of the array edge units. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 are the front view, side view and 3D view of the unit of the edge loading structure of the invention, wherein Figure 1 (a) is a front view of the unit, Figure 1 (b) is a side view of the structural unit, Figure 1 (c) is a 3D view of the structural unit.

[0013] Figure 2 Schematic diagram of a strongly coupled phased array without the edge loading structure described in the present invention.

[0014] Figure 3 It is a schematic diagram of a strongly coupled phased array array loaded with the edge loading structure described in the present invention.

[0015] Figure 4 It is a schematic diagram of an array edge antenna unit after loading the edge loading structure described in the present invention.

[0016] Figure 5 It is an active standing wave ratio (ActiveVSWR) curve of the side-firing array antenna unit when the edge loading structure described in the present invention is not loaded.

[0017] Figure 6 It is the side-firing active standing wave ratio (ActiveVSWR) curve of the array antenna unit after loading the edge loading structure described in the present invention.

[0018] Figure 7 It is an active standing wave ratio (Active VSWR) curve of 60° scanning of the E plane of the array antenna unit when the edge loading structure described in the present invention is not loaded.

[0019] Figure 8 It is an active standing wave ratio (Active VSWR) curve of 60° scanning of the E-plane of the edge-loaded structure array antenna unit of the present invention. DETAILED DESCRIPTION

[0020] Example 1.

[0021] The edge loading structure model diagram of improving the truncation effect in this embodiment is shown in FIG. Figure 1 As shown. The antenna layer dielectric substrate material is Rogers5880, with a thickness of 0.127mm and a relative dielectric constant of 2.2. Figure 1 As shown in (c), structure 1 is a semi-butterfly metal patch, printed on the reverse side of the antenna layer dielectric substrate, with a width in the z direction gradually changing from 25mm to 58mm, and a length in the y direction of 115mm. Structure 2 is a T-shaped grounding metal sheet, printed on the inner side of a 0.05mm thick polyimide dielectric substrate (relative dielectric constant 3.5), with the size of the top of the T-shaped metal sheet being 100mm*58mm, and the size of the rectangle below the T-shaped metal sheet being 10mm*65mm. Structure 3 is a resistor, welded on the T-shaped metal sheet.

[0022] In order to verify the performance of the edge loading structure proposed in the present invention, a strongly coupled phased array antenna with a working bandwidth of 4:1 is designed for verification. Figure 2As shown, the array has 2 antenna units arranged in the x direction and 16 antenna units arranged in the y direction, with the edges cut off. Due to the symmetry of the array structure, only antenna units 1 to 8 are discussed and analyzed in the following, and the spacing between units is 75 mm.

[0023] Figure 3 The array is loaded with Figure 1 (c) Schematic diagram of the strongly coupled phased array after edge loading structure.

[0024] Figure 4 It is loaded Figure 1 (c) Schematic diagram of the strongly coupled phased array edge antenna unit after the edge loading structure is shown. The half-butterfly metal patch 4 is printed on the reverse side of the antenna layer dielectric substrate 5 and connected to the coupling patch 6 of the edge antenna unit. The T-shaped metal patch 7 is printed on the dielectric substrate 11. The upper side of the T-shaped metal patch 7 is welded to the half-butterfly metal patches 4 on both sides, and the lower side of the T-shaped metal patch 7 is welded to the metal floor 8. Structure 9 is a 150Ω resistor welded to the T-shaped metal patch 7. Structure 10 is the dipole arm of the antenna unit.

[0025] Figure 5 is the active standing wave curve of the side-firing array antenna unit when the edge loading structure of the present invention is not loaded, where f L This is the lowest operating frequency of the array. Due to the truncation effect of the array, at this time, at f L At , the active standing wave ratio of antenna unit No. 1 in the array is close to 5.

[0026] Figure 6 The active standing wave curve of the side-firing array antenna unit after loading the edge loading structure of the present invention is given. It can be seen from the figure that at this time, L -4f L Within the range, the active standing wave ratio of antenna units 1-8 of the array is kept below 2.6.

[0027] Figure 7 This is the active standing wave curve of the E-plane 60° scanning of the edge loading structure array antenna unit of the present invention without loading. L -1.5f L Within the range, the active standing wave ratio of antenna units 1-3 in the array deteriorates seriously, and the active standing wave ratio at the low frequency point remains above 8. The active standing wave ratio of antenna units 4-5 in the array is L -1.5f L Within the range, there are also some frequency points where the active standing wave ratio is greater than 4.

[0028] Figure 8 The active standing wave curve of the E-plane 60° scanning of the array antenna unit after loading the edge loading structure of the present invention is given. It can be seen from the figure that at f L -4fL Within the operating frequency band, the active standing waves of all antenna units in the array are less than 3.5.

[0029] From the above comparative analysis, it can be seen that the edge loading structure of the present invention can effectively improve the edge truncation effect of the strongly coupled phased array antenna, and optimize the impedance matching of the strongly coupled phased array antenna when the side-firing and E-plane scanning angles are 60°.

[0030] The specific embodiments given above are only preferred examples of the edge loading structure for improving the truncation effect of the strongly coupled phased array. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An edge loading structure for improving the truncation effect of a strongly coupled phased array, wherein the edge loading structure is arranged at the ends of two adjacent rows of array antennas, wherein each row of antenna patches in the array antenna is independently provided with a dielectric substrate, and each dielectric substrate is vertically arranged on a metal floor; The edge loading structure comprises: a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a first half-butterfly metal patch, a second half-butterfly metal patch, a T-shaped grounding metal patch, a resistor, and a metal floor; The first dielectric substrate is integrated with the dielectric substrate of one of the two adjacent rows of the array antenna, and the second dielectric substrate is integrated with the dielectric substrate of the other of the two adjacent rows of the array antenna; the first semi-butterfly metal patch is arranged on the first dielectric substrate, and one end is connected to the coupling patch of the array antenna at the corresponding position; the second semi-butterfly metal patch is arranged on the second dielectric substrate, and one end is connected to the coupling patch of the array antenna at the corresponding position; the metal floor of the edge loading structure is the same as the metal floor of the array antenna; the two sides of the third dielectric substrate are connected to the first dielectric substrate and the second dielectric substrate, and the third dielectric substrate is perpendicular to the metal floor, and the two ends of the "1"-shaped part of the T-shaped grounding metal patch are respectively connected to the other end of the first semi-butterfly metal patch and the second semi-butterfly metal patch; the bottom end of the "1"-shaped part of the T-shaped grounding metal patch is connected to one end of the resistor, and the other end of the resistor is connected to the metal floor.

2. The edge loading structure for improving the truncation effect of a strongly coupled phased array according to claim 1, characterized in that: The third dielectric substrate is perpendicular to the first dielectric substrate and the second dielectric substrate.

3. The edge loading structure for improving the truncation effect of a strongly coupled phased array according to claim 1, characterized in that: The first half-butterfly-shaped metal patch and the second half-butterfly-shaped metal patch are right-angled trapezoids, the top side of the right-angled trapezoids is connected to the coupling patch of the array antenna, and the bottom side is connected to the T-shaped grounding metal patch.

4. The edge loading structure for improving the truncation effect of a strongly coupled phased array according to claim 1, characterized in that: Two ends of the "I"-shaped portion of the T-shaped grounding metal patch protrude from the planes of the first dielectric substrate and the second dielectric substrate.

5. The edge loading structure for improving the truncation effect of a strongly coupled phased array according to claim 3, characterized in that: The waists of the first half-butterfly-shaped metal patch and the second half-butterfly-shaped metal patch close to the metal floor are right-angle waists.

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