A wide beam circularly polarized microstrip array element suitable for AOP millimeter wave phased array

Abstract

The present invention discloses a wide beam circular polarization microstrip array element suitable for AOP millimeter wave phased array, including a radiation patch, a microstrip coupling line, a dielectric layer and a bottom floor; the radiation patch is located at the center of the upper surface of the dielectric layer; the microstrip coupling line is located at the edge of the upper surface of the dielectric layer; the bottom floor is located at the lower surface of the dielectric layer, and a rectangular gap structure, a rectangular microstrip feed line and a BGA ball planting structure are provided on the bottom floor; the radiation patch is connected to the rectangular microstrip feed line of the bottom floor through a metal via; the microstrip coupling line is also connected to the lower surface of the bottom floor through a metal via. The ball planting structure is directly interconnected with the RF front end, and has the characteristics of low loss, light weight, low cost, etc.; at the same time, it overcomes the shortcomings of conventional microstrip antennas such as narrow beam and uneven radiation, and solves the technical problems of low profile and wide coverage of existing satellite-borne phased array elements.

Description

Technical Field

[0001] The present invention relates to a satellite-borne phased array antenna technology applied in the field of satellite Internet communications, and in particular to a wide-beam circularly polarized array element suitable for an AOP millimeter-wave phased array. Background Art

[0002] With the reduction of mass manufacturing costs of satellites and the development of satellite launch technology, satellite Internet communications have become a hot research topic in the international aerospace field. Compared with traditional single satellites, high-volume-ratio satellite Internet constellation systems are more complex and put forward more technical requirements for satellite-borne phased array antennas. First of all, with the development of satellite miniaturization and the sharp reduction of satellite space resources, the envelope size and weight of satellite-borne antennas are strictly restricted. Flat-plate phased array antennas are very suitable for satellite communication applications due to their extremely low profile characteristics, but the current mainstream of satellite-borne flat-plate phased array elements is electrically interconnected through traditional types of connectors such as coaxial cables, SMP, SMA, and millimeter-wave front ends, which have the disadvantages of large size, heavy weight, and high insertion loss. Secondly, in order to meet the wide coverage requirements of satellite communications, satellite-borne array antennas need to still have high gain when scanning at large angles, which requires phased array units to have wide beam characteristics. Conventional single-layer microstrip antennas have a narrow bandwidth (only about 3%), while multi-layer microstrip antennas with wider beam widths face a huge risk of delamination failure due to inconsistent thermal expansion coefficients between the multi-layer dielectric and the intermediate bonding layer when placed in a satellite-borne high and low temperature alternating environment (conventionally about ±90 degrees). Finally, microstrip antennas often have asymmetric unit patterns on different slices due to the non-strict symmetry of the antenna structure and the conventional bias feeding method, which leads to a significant decrease in gain when scanning at large angles on certain slices during array scanning, and cannot meet the application requirements of satellite-borne antennas that want uniform full coverage in the azimuth plane. Summary of the invention

[0003] Aiming at the application of high volume ratio satellite Internet communication, a wide beam circularly polarized array element suitable for AOP (Antenna on Package) millimeter wave phased array is provided. The array element is directly interconnected with the RF front end through a BGA (BGA's full name is Ball Grid Array (PCB with ball grid array structure), which is a packaging method for integrated circuits using organic substrates.) ball planting structure, with the characteristics of low loss, light weight and low cost. At the same time, it overcomes the shortcomings of conventional microstrip antennas such as narrow beam and uneven radiation, and solves the technical problems of low profile and wide coverage of existing satellite-borne phased array elements.

[0004] The technical solution of the present invention is: a wide beam circularly polarized microstrip array element suitable for an AOP millimeter wave phased array, comprising a radiation patch, a microstrip coupling line, a dielectric layer and a bottom floor;

[0005] The radiation patch is located at the center of the upper surface of the dielectric layer; the microstrip coupling line is located at the edge of the upper surface of the dielectric layer; the bottom floor is located at the lower surface of the dielectric layer, and a rectangular gap structure, a rectangular microstrip feed line and a BGA ball planting structure are provided on the bottom floor;

[0006] The radiation patch is connected to the rectangular microstrip feed line of the bottom floor through a metal via; the microstrip coupling line is also connected to the lower surface of the bottom floor through a metal via.

[0007] Furthermore, the radiation patch is circular, and four rectangular notches are cut on the edge of the radiation patch, and the four rectangular notches are centrally symmetrically positioned relative to the center of the patch; a rectangular groove is opened on the inner side of the radiation patch, and the groove width of the rectangular groove is 0.1mm~0.2mm, and the center of the rectangular groove coincides with the center of the patch.

[0008] Furthermore, the acute angle between the line connecting the center of any one of the four rectangular notches and the center of the patch and the central axis of the long side of the rectangular groove inside the patch is 45 degrees.

[0009] Furthermore, the microstrip coupling line includes 8 rectangular microstrip strips, and one end of each two rectangular microstrip strips overlaps and is arranged at a right angle on the square upper surface of the dielectric layer; the rectangular microstrip strip is 0.1 mm wide, the long side of the rectangular microstrip strip is parallel to the edge of the dielectric layer, and the long side of the rectangular microstrip strip is 0.1 mm away from the edge of the dielectric layer.

[0010] Furthermore, the dielectric layer is a rectangular parallelepiped made of radiation-resistant material, and is provided with 5 metal through holes inside to achieve connection between the radiation patch and the bottom floor and between the microstrip coupling line and the bottom floor.

[0011] Furthermore, the five metal through holes include one feeding through hole and four grounding through holes; the feeding through hole connects the radiation patch and the rectangular microstrip feed line, the center of the contact surface between the feeding through hole and the radiation patch deviates from the center of the radiation patch, and the center of the contact surface with the rectangular microstrip feed line is on the central axis of the short side of the rectangular microstrip feed line; the four grounding through holes are respectively located at the four corners of the dielectric layer, one end of the four grounding through holes is connected to the overlapping parts of the four pairs of microstrip coupling lines one by one, and the other ends of the four grounding through holes are connected to the lower surface of the bottom floor 4.

[0012] Furthermore, the metal through hole is a metal cylinder with a diameter of 0.2 mm.

[0013] Furthermore, the center of the rectangular slot structure on the bottom floor coincides with the center of the rectangular microstrip feeder; the length and width of the rectangular slot structure are respectively greater than the length and width of the rectangular microstrip feeder, and the difference is a fixed value of 0.15 mm.

[0014] Furthermore, the BGA ball planting structure is located on the lower surface of the rectangular microstrip feeder, and the center of the contact surface and the center of the contact surface between the feeding through hole and the rectangular microstrip feeder are symmetrical relative to the central axis of the long side of the rectangular microstrip feeder.

[0015] The beneficial effects of the present invention are:

[0016] 1. The phased array elements are directly interconnected with the RF front end through the BGA ball planting structure, which has the characteristics of low loss, light weight and low cost.

[0017] 2. The phased array element adopts a single-layer microstrip antenna form, which has a simple structure and low cost. It can effectively reduce the failure risk of the antenna in the high and low temperature alternating environment on board, and meet the high reliability requirements of the onboard antenna.

[0018] 3. The phased array elements adjust the antenna pattern through near-field coupling of microstrip coupling lines. The half-power beam width is expanded to more than 95 degrees. The pattern radiates evenly and symmetrically on different sections, meeting the wide coverage requirements of satellite-borne phased array elements.

[0019] 4. The phased array elements achieve good circular polarization radiation within the working bandwidth through rectangular slots cut on the edge and inner side of the patch. The structure is simple and meets the circular polarization characteristics requirements of the satellite antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A side view of a wide beam circularly polarized microstrip array element suitable for an AOP millimeter wave phased array according to an embodiment of the present invention;

[0021] Figure 2 A front view of a wide beam circularly polarized microstrip array element suitable for an AOP millimeter wave phased array according to an embodiment of the present invention;

[0022] Figure 3 A simulated standing wave ratio curve of a wide beam circularly polarized microstrip array element suitable for an AOP millimeter wave phased array according to an embodiment of the present invention;

[0023] Figure 4 A simulated gain-frequency curve of a wide-beam circularly polarized microstrip array element applicable to an AOP millimeter-wave phased array according to an embodiment of the present invention;

[0024] Figure 5 A simulated axial ratio-frequency curve of a wide beam circularly polarized microstrip array element applicable to an AOP millimeter wave phased array according to an embodiment of the present invention;

[0025] Figure 6 A simulated half-power beamwidth-frequency curve of a wide-beam circularly polarized microstrip array element applicable to an AOP millimeter-wave phased array according to an embodiment of the present invention;

[0026] Figure 7An embodiment of the present invention provides a gain radiation pattern of a wide-beam circularly polarized microstrip array element applicable to an AOP millimeter-wave phased array and simulated at a center frequency of 29 GHz. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0028] like Figure 1 and Figure 2 As shown, a wide beam circular polarization microstrip array element suitable for AOP millimeter wave phased array includes a radiation patch 1, a microstrip coupling line 2, a dielectric layer 3 and a bottom floor 4. The radiation patch 1 is a circle with a radius of 1.1 mm, and the edge of the radiation patch is cut with 4 rectangular notches 101, 102, 103, 104 with a size of 0.5 mm*0.1 mm, which are centrally symmetrical relative to the center of the radiation patch. A rectangular groove 11 with a length of 2.1 mm and a width of 0.15 mm is opened on the inner side of the radiation patch 1. The center of the rectangular groove 11 coincides with the center of the radiation patch 1, and the angle between the central axis of its long side and the line connecting the center of the rectangular notch 102 and the center of the radiation patch is 45 degrees. The microstrip coupling line 2 comprises 8 rectangular microstrip strips 21, 22, 23, 24, 25, 26, 27 and 28 with a size of 0.1mm*1.2mm, wherein one end of each two rectangular microstrip strips overlaps and is arranged at a right angle on the square upper surface of the dielectric layer 3, and the long side of the rectangular microstrip strip is parallel to the edge of the dielectric layer, with a distance of 0.1mm. The dielectric layer 3 is made of radiation-resistant material with a dielectric constant of 3.47, with a size of 5.1mm*5.1mm*1mm, and a feed through hole 31 with a radius of 0.1mm is provided inside the dielectric layer 3, and the feed through hole 31 connects the radiation patch 1 and the bottom floor 4, and the dielectric layer 3 is also provided with grounding through holes 32, 33, 34, 35 with a radius of 0.1mm, and one end of the four grounding through holes is connected to the overlapping part of the four pairs of microstrip coupling lines one by one, and the other end of the four grounding through holes is connected to the lower surface of the bottom floor 4. The center of the contact surface between the feeding through hole 31 and the radiation patch 1 deviates from the center of the radiation patch 1 by 0.4 mm. The bottom floor 4 is located on the lower surface of the dielectric layer 3, and a rectangular gap structure 41, a rectangular microstrip feed line 42 and a BGA ball implantation structure 43 are provided on the bottom floor 4. The size of the rectangular gap structure 41 is 0.8 mm*2.8 mm, the size of the rectangular microstrip feed line 42 is 0.5 mm*2.5 mm, and the center of the rectangular gap structure 41 coincides with the center of the rectangular microstrip feed line 42. The BGA ball implantation structure 43 is a metal hemisphere with a radius of 0.5 mm, which is located on the lower surface of the rectangular microstrip feed line 42, and the center of the contact surface and the center of the contact surface between the feeding through hole 31 and the rectangular microstrip feed line 42 are symmetrical relative to the central axis of the long side of the rectangular microstrip feed line 42.

[0029] Based on the above design scheme, the corresponding simulation results are given below. Figure 3-7 The simulated standing wave ratio curve, simulated gain-frequency curve, simulated axial ratio-frequency curve, simulated half-power beam width-frequency curve and the simulated gain radiation pattern of the center frequency at 29GHz are shown respectively. It can be seen that the phased array element is a single-layer microstrip structure with an envelope size of 5.1mm*5.1mm*1mm. It is directly interconnected with the RF front end through the BGA ball planting structure, and has the characteristics of simple structure, low profile, light weight and low cost. It achieves VSWR <1.5 in the full frequency band of 28.5GHz-31.5GHz, gain greater than 5.5dBi, axial ratio less than 3dB, half-power beam width greater than 95 degrees, and the radiation gain difference of each section within the half-power beam width is less than 0.5dB. It can perform effective circular polarization high-gain uniform radiation within a working bandwidth of more than 10%, meeting the requirements of low profile, wide coverage and high reliability of satellite-borne antennas for high volume ratio satellite Internet communication applications.

[0030] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A wide beam circularly polarized microstrip array element suitable for AOP millimeter wave phased array, characterized by: Includes radiation patch, microstrip coupling line, dielectric layer and bottom floor; The radiation patch is located at the center of the upper surface of the dielectric layer; the microstrip coupling line is located at the edge of the upper surface of the dielectric layer; The bottom floor is located on the lower surface of the dielectric layer, and a rectangular gap structure, a rectangular microstrip feeder and a BGA ball planting structure are provided on the bottom floor; The radiation patch is connected to the rectangular microstrip feed line of the bottom floor through a metal via; the microstrip coupling line is also connected to the lower surface of the bottom floor through a metal via; The radiation patch is circular, and four rectangular notches are cut on the edge of the radiation patch, and the four rectangular notches are centrally symmetrical relative to the center of the patch; a rectangular groove is opened on the inner side of the radiation patch, and the groove width of the rectangular groove is 0.1mm to 0.2mm, and the center of the rectangular groove coincides with the center of the patch; The center of the rectangular slot structure on the bottom floor coincides with the center of the rectangular microstrip feeder; the length and width of the rectangular slot structure are respectively greater than the length and width of the rectangular microstrip feeder, and the difference is a fixed value of 0.15 mm; The BGA ball planting structure is located on the lower surface of the rectangular microstrip feeder, and the center of the contact surface and the center of the contact surface of the feeding through hole and the rectangular microstrip feeder are symmetrical relative to the long side center axis of the rectangular microstrip feeder.

2. According to claim 1, a wide beam circularly polarized microstrip array element suitable for an AOP millimeter wave phased array, characterized in that: The acute angle between the line between the center of any one of the four rectangular notches and the center of the patch and the central axis of the long side of the rectangular groove inside the patch is 45 degrees.

3. The wide beam circularly polarized microstrip array element suitable for AOP millimeter wave phased array according to claim 1, characterized in that: The microstrip coupling line comprises 8 rectangular microstrip strips, and one end of every two rectangular microstrip strips overlaps and is arranged at a right angle on the square upper surface of the dielectric layer; the rectangular microstrip strip is 0.1 mm wide, the long side of the rectangular microstrip strip is parallel to the edge of the dielectric layer, and the long side of the rectangular microstrip strip is 0.1 mm away from the edge of the dielectric layer.

4. The wide beam circularly polarized microstrip array element suitable for AOP millimeter wave phased array according to claim 3, characterized in that: The dielectric layer is a rectangular parallelepiped, made of radiation-resistant material, and is provided with 5 metal through holes inside to achieve connection between the radiation patch and the bottom floor, and between the microstrip coupling line and the bottom floor.

5. A wide beam circularly polarized microstrip array element suitable for an AOP millimeter wave phased array according to claim 4, characterized in that: The five metal through holes include one feeding through hole and four grounding through holes; the feeding through hole connects the radiation patch and the rectangular microstrip feed line, the center of the contact surface between the feeding through hole and the radiation patch deviates from the center of the circle of the radiation patch, and the center of the contact surface with the rectangular microstrip feed line is on the central axis of the short side of the rectangular microstrip feed line; the four grounding through holes are respectively located at the four corners of the dielectric layer, one end of the four grounding through holes is connected to the overlapping parts of the four pairs of microstrip coupling lines one by one, and the other ends of the four grounding through holes are connected to the lower surface of the bottom floor.

6. The wide beam circularly polarized microstrip array element suitable for AOP millimeter wave phased array according to claim 5, characterized in that: The metal through hole is a metal cylinder with a diameter of 0.2 mm.

Images