Wide-angle scanning transmission array antenna based on inclined beam unit

Abstract

The invention discloses a wide-angle scanning transmission array antenna based on an inclined beam unit. The wide-angle scanning transmission array antenna comprises a transmission array plane and a feed source horn which is arranged opposite to the transmission array plane and is adjustable in position. The transmission array surface comprises a plurality of array surface units, each array surface unit comprises a transmitting unit and a receiving unit, the transmitting units and the receiving units are connected through connecting metal through holes and share the same metal floor, and two rows of metal through holes which are arranged in a staggered mode are formed between the transmitting units and the metal floor so that the transmitting units can emit inclined wave beams. Phase regulation and control are carried out on the transmission array plane through a bifocus phase compensation method, and the bifocus phase compensation method comprises the steps that phase compensation values are calculated at the two virtual focuses respectively, and the average value is taken to serve as a compensation phase needed by an array plane unit. According to the invention, the emission unit with the inclined wave beam is adopted to regulate and control the amplitude of the emitted wave, and a bifocus phase compensation method is adopted, so that the phase error in the scanning process can be greatly reduced, and the scanning angle range is further expanded.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a wide-angle scanning transmission array antenna based on tilted beam elements. Background Technology

[0002] With the rapid development of wireless communication technology and radar systems, beam-scanning antennas are increasingly widely used in related fields, and their performance requirements are becoming more and more stringent. Transmission array antennas, as a new type of array antenna structure that has emerged in recent years, have gradually developed into a promising technical solution for realizing beam-scanning functions due to their advantages such as high gain, no need for complex feeding networks, and low feeding loss.

[0003] One way to achieve low-cost beam scanning for transmission array antennas is by shifting the feed. Changing the beam direction is achieved by moving the feed away from the focal point to adjust the incident phase distribution. However, this method can only achieve a very limited 3dB gain roll-off scanning angle range, typically only ±25°. The core reason is that the transmission array antenna has only one ideal focal point, which causes defocusing during scanning. As the feed offset distance increases, the phase compensation error also increases rapidly, leading to a significant drop in gain. To improve the beam scanning range of transmission array antennas, various methods have been proposed in the published literature. For example, X. Yang et al. used a four-focal phase compensation method, setting four virtual focal points outside the ideal focal point and arithmetically averaging the phase compensation values ​​calculated at the virtual focal points. Based on this, they also used a particle swarm optimization algorithm for phase optimization (X. Yang, C. Wang, Y. Ji, J. Hu and H. Wong, "Two-Dimensional Beam-ScanningBroadband Circularly Polarized Transmitarray With Low Sidelobe Level," IEEE Trans. Antennas Propag, vol. 73, no. 8, pp. 5408-5419, Aug. 2025.). J. Lai et al. proposed an angle-multiplexed multifocal phase compensation method, combining angle multiplexing technology based on OAM metasurfaces with multifocal compensation (J. Lai, X. Lv, MM Rahman, MAI Oni, S. Dey and Y. Yang, "An Angle-Multiplexed Multifocal Method for D-Band"). "2-D Beam-Scanning Transmitarray Leveraging 3-D Transmission Line Component," IEEE Antennas Wireless Propag. Lett., vol. 24, no. 3, pp. 731-735, March 2025.); Y. Hou et al. divided the array into multiple regions based on the sliding aperture technique, illuminating only a portion of the region when the feed moves, and performing separate phase compensation design for each region (Y. Hou, L. Chang, Y. Li, Z. Zhang and Z.).Feng, "Linear Multibeam Transmitarray Based on the Sliding Aperture Technique," IEEE Trans. Antennas Propag, vol. 66, no. 8, pp. 3948-3958, Aug. 2018.; P. Mei et al. proposed an offset focus symmetric phase compensation method by analyzing various factors that lead to gain reduction during scanning, symmetrically correcting the phase distribution calculated by a single virtual focus (P. Mei, GF Pedersen and S. Zhang, "Performance Improvement of Mechanically Beam-Steerable Transmitarray Antennas by Using Offset Unifocal Phase Symmetry," IEEE Trans. Antennas Propag, vol. 71, no. 1, pp. 1129-1134, Jan. 2023.). However, these methods still have limited improvement on the scanning angle. Furthermore, most of the reported schemes currently focus on improving phase errors during scanning. Summary of the Invention

[0004] This invention aims to solve the problem of narrow scanning angle range in the beam scanning performance of transmission array antennas, and provides a wide-angle scanning transmission array antenna based on tilted beam elements. By using beam-tilted transmission array elements, the amplitude distribution of the emitted electromagnetic waves can be effectively controlled, thereby improving the scanning angle range. By adopting a dual-focus phase error compensation method, the phase error generated during scanning can be reduced. Through dual control of electromagnetic wave amplitude and phase, the antenna performance is improved.

[0005] To achieve the objective of this invention, this invention provides a wide-angle scanning transmission array antenna based on a tilted beam unit, comprising a transmission array surface and a feed horn disposed opposite to the transmission array surface and whose position is adjustable. The transmission array includes multiple array elements, each array element includes a transmitting element and a receiving element. The transmitting element and the receiving element are connected by connecting metal through holes and share the same metal ground plane. Two rows of staggered metal through holes are provided between the transmitting element and the metal ground plane to enable the transmitting element to emit a tilted beam. The transmission array uses a dual-focus phase compensation method for phase control. The dual-focus phase compensation method involves calculating the phase compensation value at two virtual focal points and taking the average value as the compensation phase required for the array element.

[0006] A further improvement to the present invention includes a dielectric support, wherein the transmission array surface and the feed horn are connected via the dielectric support, and the position of the feed horn on the dielectric support is adjustable.

[0007] A further improvement to the present invention is that, in the dual-focus phase compensation method, the array elements on the transmission array surface... Required compensation phase It is obtained through the following formula:

[0008]

[0009]

[0010] In the formula, and The compensation phases calculated at virtual focus 1 and virtual focus 2 are respectively. The compensation phase required for the final array element, It is the free space wavenumber. It's the focal length. It is the distance between the two virtual focal points, and α is the beam deflection angle. and They are respectively numbered ( , The horizontal and vertical coordinates of the array element.

[0011] A further improvement to the present invention is that the transmitting elements on both sides of the transmission array surface are mirror-distributed, for The required compensation phase correction for array elements >7 is +180°.

[0012] In a further improvement to the present invention, the transmitting unit is a monopole and the receiving unit is a chamfered patch.

[0013] In a further improvement of the present invention, a U-shaped groove is provided on the outer side of the chamfered patch corresponding to the connecting metal through hole.

[0014] In a further improvement of the present invention, in the transmission array, the chamfered patch of each array element rotates by a preset angle around the connecting metal through hole at its center position to achieve the control of the transmission phase.

[0015] In a further improvement of the present invention, the transmission array includes a first dielectric plate, a second dielectric plate, and a third dielectric plate stacked from top to bottom. The transmitting unit and the receiving unit of the array element are respectively disposed on the upper surface of the first dielectric plate and the lower surface of the third dielectric plate. A common metal base plate is disposed between the second dielectric plate and the third dielectric plate. Two rows of staggered metal through holes are respectively disposed on the first dielectric plate and the second dielectric plate.

[0016] A further improvement to the present invention is to change the amplitude distribution of the emitted electromagnetic waves by adjusting the arrangement and tilt angle of the tilted beams in the transmission array.

[0017] A further improvement to the present invention is that the tilt of the radiation pattern can be flexibly controlled by adjusting the phase position of the two rows of metal through holes.

[0018] Compared with the prior art, the present invention can achieve at least the following beneficial effects: (1) On the transmission array, the present invention uses a transmitting unit with tilted beams to control the amplitude of the emitted wave. By adjusting the arrangement and tilt angle of the tilted beams, the amplitude distribution of the emitted electromagnetic wave can be effectively changed, and the scanning angle range of the antenna can be significantly improved.

[0019] (2) In terms of phase control, the present invention adopts a dual-focus phase compensation method, which can significantly reduce the phase error during the scanning process and further improve the scanning angle range.

[0020] (3) Through the study of the embodiments of the present invention, it was found that the proposed transmission array antenna can achieve a scanning range of ±44° under the condition of 3dB gain roll-off, with a peak gain of 21.02dBi, which is better than the current technical level. Attached Figure Description

[0021] Figure 1 This is a full view of a wide-angle scanning transmission array antenna based on tilted beam elements provided in an embodiment of the present invention.

[0022] Figure 2 This is a side view of a wide-angle scanning transmission array antenna based on a tilted beam element provided in an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the array element in an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the staggered arrangement of two rows of metal through holes in an embodiment of the present invention.

[0025] Figure 5 This is a top view of the first dielectric plate and the first metal layer on its upper surface in an embodiment of the present invention.

[0026] Figure 6This is a bottom view of the second dielectric plate and its lower surface second metal layer in an embodiment of the present invention.

[0027] Figure 7 This is a bottom view of the third dielectric plate and its lower surface third metal layer in an embodiment of the present invention.

[0028] Figure 8 This is a schematic diagram of the conventional beam and the tilted beam arrangement structure in the embodiments of the present invention.

[0029] Figure 9 This is a schematic diagram illustrating the principle and corresponding phase distribution of the dual-focus phase compensation method in this embodiment of the invention.

[0030] Figure 10 This is the radiation pattern of the transmitting unit in this embodiment of the invention.

[0031] Figure 11 This is a schematic diagram of the transmission coefficient of the transmission array element in an embodiment of the present invention.

[0032] Figure 12 This is a schematic diagram of the S-parameter curve of the antenna in an embodiment of the present invention.

[0033] Figure 13 This is a schematic diagram of the beam scanning of the antenna at the center frequency of 32GHz in an embodiment of the present invention.

[0034] Figure 14 This is a schematic diagram of the antenna gain performance in an embodiment of the present invention.

[0035] Figure 15 This is a schematic diagram of the antenna beam scanning at the center frequency without using dual-focus phase compensation in an embodiment of the present invention.

[0036] Figure 16 This is a schematic diagram of the antenna gain performance without using dual-focus phase compensation in an embodiment of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] This invention provides a wide-angle scanning transmission array antenna based on tilted beam elements, the full view and side view of which are shown below. Figure 1 , Figure 2 As shown.

[0039] The transmission array antenna includes a transmission array surface 11, a dielectric support 12, and a feed horn 13. The transmission array surface 11 comprises three stacked dielectric substrates, defined from top to bottom as a first dielectric substrate 21, a second dielectric substrate 22, and a third dielectric substrate 23. The dielectric support 12 has two rows of mounting holes (screw holes) to fix the feed horn 13. The position of the feed horn 13 on the dielectric support 12 is adjustable; beam scanning is achieved by moving the fixed position of the feed horn 13 on the dielectric support 12 along the x-direction. The phase center of the feed horn 13 coincides with the focal point of the transmission array surface 11. The coordinate system is established as follows: a rectangular coordinate system... x shaft and y The axes are parallel to the two rectangular sides of the PCB board, and the maximum radiation direction of the array points to the z-axis. In one embodiment of the present invention, the first dielectric substrate 21, the second dielectric substrate 22, and the third dielectric substrate 23 are all Rogers 5880, with a dielectric constant of 2.2 and a loss tangent of 0.0009. All dielectric substrates have a thickness of 0.787 mm and a size of 85 mm × 85 mm. The spacing between adjacent mounting holes on the dielectric support 12 is 10 mm, and the focal length on the transmission array surface 11 is set to 35 mm.

[0040] The dielectric support 12 includes a base plate and a support column. The base plate and the transmission array 11 are connected by the support column, and the feed horn 13 is movably mounted on the base plate.

[0041] The transmission array 11 includes multiple array elements, and the full view and top view of the array elements are shown below. Figure 3 , Figure 4 As shown, the array element is a transceiver structure. The monopole 31 and the chamfered patch 36 serve as the transmitting and receiving units, respectively, connected by a metal through-hole 34 and sharing the same metal ground plane 35. Below the monopole 31, two rows of staggered metal through-holes are arranged, offset along the x-axis. The first row of metal through-holes 32 is located on the first dielectric plate 21, and the second row of metal through-holes 33 is located on the second dielectric plate 22. These two rows of metal through-holes can be equivalent to a tilted reflector to tilt the transmitting unit beam. The chamfered patch 36 is used to receive circularly polarized waves, and the U-shaped groove 37 loaded in its center improves the matching with the monopole 31. In one embodiment of the invention, the transmission array 11 comprises 196 array elements arranged in a 14×14 configuration, with an aperture size of 70mm×70mm and a focal diameter ratio of 0.5.

[0042] A top view of the first dielectric plate 21 and the first metal layer 41 on its upper surface is shown below. Figure 5As shown. A first metal layer 41 is disposed on the upper surface of the first dielectric plate 21. Monopoles 31 are disposed on the first metal layer 41 in a periodic arrangement with a period size of 5 mm. The monopoles 31 are distributed in a mirror symmetrical distribution about the y-axis with the y-axis as the central axis.

[0043] The bottom view of the second dielectric substrate 22 and its lower surface second metal layer 35 is shown in Figure 6. The lower surface of the second dielectric substrate 22 is provided with a second metal layer 35, which serves as the metal reflector of the monopole 31 and the metal ground plane of the chamfered patch 36. A circular patch 51 is cut out at the position corresponding to each connecting metal through hole 34 to separate the connecting metal through hole 34 from the second metal layer 35.

[0044] A bottom view of the third dielectric plate 23 and its lower surface third metal layer 61 is shown below. Figure 7 As shown. A third metal layer 61 is provided on the lower surface of the third dielectric substrate 23. The third metal layer 61 is provided with periodically arranged chamfered patches 36 with a period size of 5 mm. Each chamfered patch 36 rotates a certain angle around the connecting metal through hole 34 at its center position.

[0045] In terms of working principle, the feed horn 13 emits a circularly polarized wave after being excited. This circularly polarized wave is then received by the receiving unit on the transmission array and transmitted to the transmitting unit for radiation, where it is a linearly polarized wave. By employing a beam-tilted transmitting unit, the amplitude distribution of the radiated electromagnetic wave can be effectively controlled, alleviating the problem of rapid gain drop during large-angle scanning and thus improving the antenna's scanning angle range. In this embodiment of the invention, the beam tilt of the transmitting unit is achieved by setting two rows of staggered metal through-holes. The two rows of metal through-holes can be equivalent to a tilted reflector, causing the electromagnetic wave radiated by the monopole 31 to propagate in a specific direction, thereby causing the radiation pattern to tilt. The degree of tilt of the radiation pattern can be flexibly controlled by adjusting the phase position of the two rows of metal through-holes. Unlike the beam arrangement of the transmitting unit in a traditional transmission array antenna, to achieve wide-angle scanning in the xoz plane, the transmitting unit is mirror-symmetrically distributed about the y-axis with the y-axis centerline of the array as the axis, thus forming a beam pattern as shown in the figure. Figure 8 The tilted beam arrangement structure shown can be optimized by full-wave simulation, where the beam tilt angle θ required for each specific unit can be obtained.

[0046] In traditional transmission array antenna design, phase compensation calculations follow Fermat's principle, achieving accurate phase compensation at the focal point. However, as the feed source moves further away from the focal point, the phase compensation error increases, leading to a significant decrease in scanning gain. In one embodiment of this invention, a dual-focal-point phase compensation method is employed, the principle of which and the corresponding phase distribution are as follows: Figure 9 As shown, phase compensation values ​​are calculated at the two virtual foci. Since the transmission array has only one phase distribution, the phase compensation values ​​calculated at the two foci are averaged to obtain the final phase distribution. Specifically, in a dual-focus design, the array elements on the transmission array surface... Required compensation phase It is obtained through the following formula:

[0047]

[0048]

[0049] in and The compensation phases calculated at virtual focus 1 and virtual focus 2 are respectively. The compensation phase required for the final array element, It is the free space wavenumber. It's the focal length. It is the distance between the two virtual focal points, and α is the beam deflection angle. and They are respectively numbered ( , The horizontal and vertical coordinates of the array elements are, in some embodiments of the present invention, , =1,2,3,···,14.

[0050] In one embodiment of the present invention, the distance between the two virtual focal points The beam is set to 35mm, and the beam deflection angle α is set to 25°. Since the transmitting elements on both sides of the transmission array are mirror-image distributed, for... The required compensation phase for array elements with a value of >7 should be corrected to: +180°.

[0051] Regarding unit performance, the radiation pattern of the transmitting unit is as follows: Figure 10 As shown, it can be seen that under the action of the tilted reflector, the tilt angle of the radiation pattern of the transmitting element in the xz plane reaches 40°, and the cross-polarization is good. The transmission coefficient of the array element is as follows: Figure 11 As shown, the transmission loss is maintained at less than -3dB in the 29.5-33GHz range, and less than -1dB at the center frequency of 32GHz, indicating good transmission performance. The transmission phase can be adjusted by rotating the chamfered patch 36 around the connecting metal through hole 34. Since the receiving unit is rotated, the rotation angle is opposite to the change in transmission phase, thus a transmission unit with arbitrary compensated phase can be obtained.

[0052] Regarding antenna performance, the S-parameters are as follows: Figure 12 As shown, within the 29.5GHz-33.5GHz frequency band, |S11 | Less than -10dB, good impedance matching. Figure 13 To illustrate the antenna's beam scanning at the center frequency of 32 GHz, seven beam orientations were obtained by moving the feed horn in 10 mm steps along the x-direction: -44°, -30°, -16°, 0°, 17°, 30°, and 44°. This was combined with... Figure 14 It can be seen that the antenna can achieve a scan loss of less than 3dB, a sidelobe level of less than -12dB, and a peak gain of 21.02dBi within a scan angle range of ±44°. To verify the improvement in scan angle range achieved by the tilted beam scheme, Figure 15 , Figure 16 The beam scanning performance of the antenna at the center frequency without dual-focus phase compensation is presented. Five beam orientations were obtained by moving the feed horn in 12.5mm steps along the x-direction: -36°, -17°, 0°, 17°, and 36°. Under these conditions, the antenna can achieve a scanning loss of 3.2dB within a scanning angle range of ±36°. Comparing the beam scanning performance with and without dual-focus phase compensation leads to the conclusion that a tilted beam scheme can improve the antenna's scanning angle range, and the scanning angle range is further improved by combining it with dual-focus phase compensation.

[0053] In summary, the transmission array antenna proposed in this embodiment of the invention has high gain and a wide beam scanning range, and its beam scanning capability is at a leading level among similar transmission array antennas.

[0054] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wide-angle scanning transmission array antenna based on tilted beam elements, characterized in that, It includes a transmission array surface and a feed horn that is positioned opposite to the transmission array surface and whose position is adjustable. The transmission array includes multiple array elements, each array element includes a transmitting element and a receiving element. The transmitting element and the receiving element are connected by connecting metal through holes and share the same metal ground plane. Two rows of staggered metal through holes are provided between the transmitting element and the metal ground plane to enable the transmitting element to emit a tilted beam. The transmission array uses a dual-focus phase compensation method for phase control. The dual-focus phase compensation method involves calculating the phase compensation value at two virtual focal points and taking the average value as the compensation phase required for the array element.

2. The wide-angle scanning transmission array antenna based on tilted beam elements according to claim 1, characterized in that, It also includes a dielectric support, the transmission array surface and the feed horn are connected through the dielectric support, and the position of the feed horn on the dielectric support is adjustable.

3. A wide-angle scanning transmission array antenna based on tilted beam elements according to claim 1, characterized in that, In the dual-focus phase compensation method, the array elements on the transmission array surface... Required compensation phase It is obtained through the following formula: In the formula, and The compensation phases calculated at virtual focus 1 and virtual focus 2 are respectively. The compensation phase required for the final array element, It is the free space wavenumber. It's the focal length. It is the distance between the two virtual focal points, and α is the beam deflection angle. and They are respectively numbered ( , The horizontal and vertical coordinates of the array element.

4. A wide-angle scanning transmission array antenna based on tilted beam elements according to claim 3, characterized in that, The transmitting elements on both sides of the transmission array are arranged in a mirror image. The required compensation phase correction for array elements >7 is +180°.

5. A wide-angle scanning transmission array antenna based on tilted beam elements according to claim 1, characterized in that, The transmitting unit is a monopole, and the receiving unit is a chamfered patch.

6. A wide-angle scanning transmission array antenna based on tilted beam elements according to claim 5, characterized in that, The chamfered patch has a U-shaped groove on the outside corresponding to the connecting metal through hole.

7. A wide-angle scanning transmission array antenna based on tilted beam elements according to claim 5, characterized in that, In the transmission array, the chamfered patch of each array element rotates by a preset angle around the connecting metal through hole at its center position to achieve the control of the transmission phase.

8. A wide-angle scanning transmission array antenna based on tilted beam elements according to claim 1, characterized in that, The transmission array includes a first dielectric plate, a second dielectric plate, and a third dielectric plate stacked from top to bottom. The transmitting unit and the receiving unit of the array element are respectively disposed on the upper surface of the first dielectric plate and the lower surface of the third dielectric plate. A common metal base plate is disposed between the second and third dielectric plates. Two rows of staggered metal through holes are respectively disposed on the first and second dielectric plates.

9. A wide-angle scanning transmission array antenna based on tilted beam elements according to claim 1, characterized in that, The amplitude distribution of the emitted electromagnetic waves can be changed by adjusting the arrangement and tilt angle of the tilted beams in the transmission array.

10. A wide-angle scanning transmission array antenna based on tilted beam elements according to any one of claims 1-9, characterized in that, The tilt of the radiation pattern can be flexibly controlled by adjusting the phase position of the two rows of metal through holes.

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