A circularly polarized grid package antenna based on HDI technology

Abstract

The present invention belongs to the field of wireless communication technology, and provides a circularly polarized grid packaged antenna based on the HDI process to solve the transmission and reception problems of circularly polarized electromagnetic waves in the 5G millimeter wave frequency band. The grid packaged antenna of the present invention has broadband characteristics and is suitable for signal transmission in the 5G millimeter wave frequency band; the HDI process is adopted to reduce the manufacturing cost; at the same time, the open-loop structure is used as the short side of the grid array antenna to achieve excellent circular polarization performance, and it helps the antenna to receive electromagnetic waves of any polarization, and also enables the antenna's radiated waves to be received by any polarized antenna; the arc structure replaces the straight long side of the traditional grid array antenna, which not only improves the performance of the antenna, but also greatly reduces the size of the package. In summary, the present invention provides a circularly polarized grid packaged antenna based on the HDI process for use in the 5G millimeter wave frequency band, which can achieve broadband characteristics, while significantly improving the circular polarization performance of the antenna, reducing the size of the package, and reducing the packaging cost.

Description

Technical Field

[0001] The present invention belongs to the field of wireless communication technology, relates to millimeter wave integrated circuits and packaged antenna technology, and in particular provides a packaged antenna based on an HDI process for use in a 5G millimeter wave frequency band loaded with a circularly polarized grid array antenna. Background Art

[0002] The rapidly emerging next-generation 5G millimeter wave communication is the future development direction of mobile communications. Compared with sub-6G, it can bring faster and better transmission rates and transmission effects; in addition, 5G wireless communication systems require highly integrated radio access solutions. The AIP packaged antenna is derived from the concept of SIP system packaging. It has the characteristics of small size and high integration, and has more prominent advantages in millimeter wave applications. Compared with separate antennas or on-chip antennas, packaged antenna solutions become more feasible at millimeter wave frequencies because the size and spacing of antenna elements are comparable to the wavelength; specifically, compared with separate antennas, embedding the antenna in the package substrate can reduce the overall interconnection length between the RFIC and the antenna, thereby minimizing feed line losses and improving radiation efficiency; compared with on-chip antennas, packaged antennas have higher gain and can more effectively deal with the problem of increased transmission loss in the medium as the frequency increases.

[0003] At present, the processes for packaging antennas are mainly divided into three types: low temperature co-fired ceramic technology (LTCC), high density interconnection process (HDI) and fan-out wafer-level packaging process (FOWLP); compared with LTCC, the HDI process has a higher interconnection density, very few packaging layers, and a smaller size. HDI uses an organic substrate with a low dielectric constant, and the antenna achieves a larger bandwidth, and higher gain and radiation efficiency; compared with the FOWLP process, HDI has a great cost advantage and reduces the manufacturing difficulty and manufacturing cost; it can be seen that HDI has more industrial value, and therefore, the present invention provides a packaged antenna based on the HDI process for loading a circularly polarized grid array antenna in the 5G millimeter wave band. Summary of the invention

[0004] The purpose of the present invention is to provide a circularly polarized grid packaged antenna based on the HDI process to solve the problem of transmitting and receiving circularly polarized electromagnetic waves in the 5G millimeter wave frequency band; and the present invention can significantly improve the circular polarization performance of the antenna and reduce the antenna size and packaging volume.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A circularly polarized grid package antenna based on HDI process, comprising: a lower dielectric layer 1, a core layer 2, an upper dielectric layer 3 and a grid array antenna 5 stacked in sequence from bottom to top, wherein the grid array antenna 5 is connected to a signal end at the bottom of the lower dielectric layer through a copper via 4 through the upper dielectric layer, the core layer and the lower dielectric layer; characterized in that:

[0007] The grid array antenna is composed of a central unit and side units spliced ​​on both sides thereof; the central unit is in the shape of a "sun", consisting of two first open-loop structures 5-1, one second open-loop structure 5-2 and four first arc structures 5-3, wherein the second open-loop structure serves as the middle horizontal edge, the first open-loop structure serves as the horizontal edges on both sides, and the first arc structure serves as the vertical edge; the side units are in an open structure, consisting of two second open-loop structures 5-2 and one second arc structure 5-4, wherein the second open-loop structure serves as the horizontal edge, and the second arc structure serves as the vertical edge; the open ends of the side units are respectively spliced ​​to the middle position of the first arc structure of the central unit; the grid array antenna is in a symmetrical structure along the center line of the vertical edge direction.

[0008] Furthermore, the first open-loop structure 5-1 and the second open-loop structure 5-2 are both in an "Ω" shape, consisting of an open circular ring and an "L"-shaped branch spliced ​​at its two open ends; the open circular ring of the second open-loop structure 5-2 is also loaded with an open branch, and the open branch is located in the middle position, and the end of the "L"-shaped branch in the second open-loop structure 5-2 is linearly widened.

[0009] Furthermore, in the first open-loop structure 5-1 and the second open-loop structure 5-2, the opening angles of the open circular rings are the same, which are both 58°.

[0010] Furthermore, the circumferences of the first open-loop structure 5 - 1 and the second open-loop structure 5 - 2 are the same, both being half the wavelength of the electromagnetic wave of the operating frequency in free space.

[0011] Furthermore, the first arc structure 5-3 and the second arc structure 5-4 adopt the same structure, and are respectively composed of a first semicircular ring, a second semicircular ring, a third semicircular ring and a fourth semicircular ring of the same size spliced ​​in sequence; the centers of the first semicircular ring, the second semicircular ring, the third semicircular ring and the fourth semicircular ring are located on the same vertical edge, the first semicircular ring and the fourth semicircular ring are located on the same side of the vertical edge, and the second semicircular ring and the third semicircular ring are located on the other side of the vertical edge.

[0012] Furthermore, the width of the second arc-shaped structure 5 - 4 is greater than the width of the first arc-shaped structure 5 - 3 .

[0013] Furthermore, the circumferences of the first arc-shaped structure 5 - 3 and the second arc-shaped structure 5 - 4 are the same, which are both the wavelengths of electromagnetic waves of the working frequency in free space.

[0014] The beneficial effects of the present invention are:

[0015] The present invention provides a circularly polarized grid package antenna based on HDI technology. The grid array antenna converts the horizontal side of the traditional grid array antenna into an open-loop structure. Since the antenna radiates electromagnetic waves with the same direction and proportional to the current on the strip line, the synthetic electric field of the electromagnetic waves radiated from each side of the open-loop structure rotates uniformly at a rotation speed of one circle per cycle relative to time in a direction perpendicular to the surface of the substrate, thereby realizing circular polarization;

[0016] Since the reverse current flowing along the loop will generate cross-polarization radiation, resulting in a larger axial ratio and lower gain, an open-circuit branch is added to the second open-loop structure 5-2 according to the current distribution to prevent the open-loop resonance, thereby reducing the axial ratio and increasing the gain;

[0017] In order to reduce the area, shorten the spacing between the radiation edges and thus improve the impedance bandwidth, the vertical edge of the traditional grid array antenna is designed to be composed of a first semicircular ring, a second semicircular ring, a third semicircular ring and a fourth semicircular ring of the same size spliced ​​in sequence; the centers of the first semicircular ring, the second semicircular ring, the third semicircular ring and the fourth semicircular ring are located on the same vertical edge, the first semicircular ring and the fourth semicircular ring are located on the same side of the vertical edge, and the second semicircular ring and the third semicircular ring are located on the other side of the vertical edge.

[0018] In order to achieve 50Ω impedance matching, the end of the "L"-shaped branch in the second open-loop structure 5-2 is linearly widened, and the width of the second arc structure 5-4 is increased, which is manifested as the width of the second arc structure 5-4 is greater than the width of the first arc structure 5-3.

[0019] In addition, the packaged antenna uses the HDI process to package the chip to achieve high-density interconnection; the use of a low dielectric constant substrate improves the circular polarization and gain of the antenna. At the same time, the use of the HDI process also reduces the cost of packaging and increases the possibility of mass production.

[0020] In summary, the present invention provides a circularly polarized grid packaged antenna based on the HDI process for application in the 5G millimeter wave frequency band, which can significantly improve the circular polarization performance of the antenna and reduce the size of the antenna and the volume of the package. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the cross-sectional structure of the grid package antenna based on the HDI process of the present invention.

[0022] Figure 2 It is a schematic diagram of the structure of the grid array antenna in the present invention.

[0023] Figure 3It is a structural schematic diagram of the first open-loop structure in the present invention.

[0024] Figure 4 It is a schematic structural diagram of the second open-loop structure in the present invention.

[0025] Figure 5 It is a schematic structural diagram of the first arc structure and the second arc structure in the present invention.

[0026] Figure 6 Schematic diagram of the structure of a traditional grid antenna.

[0027] Figure 7 : is the return loss curve of the grid package antenna in the embodiment of the present invention.

[0028] Figure 8 Graph 1 is a gain curve of the grid package antenna in an embodiment of the present invention.

[0029] Fig. 9 : is an axial ratio curve of the grid package antenna in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and technical effect of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0031] This embodiment provides a grid package antenna based on HDI technology for 5G millimeter wave frequency band, and its structure is as follows: Figure 1 As shown, it specifically includes: a lower dielectric layer 1, a core layer 2, an upper dielectric layer 3 and a grid array antenna 5 stacked in sequence from bottom to top, wherein the grid array antenna 5 is connected to the signal end at the bottom of the lower dielectric layer through a copper via 4 through the upper dielectric layer, the core layer and the lower dielectric layer; more specifically:

[0032] The grid array antenna is as follows Figure 2 As shown, it is composed of a central unit and side units spliced ​​on both sides thereof; the central unit is in a "sun" shaped structure, consisting of two first open-loop structures 5-1, one second open-loop structure 5-2 and four first arc structures 5-3, wherein the second open-loop structure serves as the middle horizontal side, the first open-loop structure serves as the horizontal sides, and the first arc structure serves as the vertical side; the side unit is in an open structure, consisting of two second open-loop structures 5-2 and one second arc structure 5-4, wherein the second open-loop structure serves as the horizontal side, and the second arc structure serves as the vertical side; the open ends of the side units are respectively spliced ​​to the middle position of the first arc structure of the central unit; the center line of the grid array antenna along the vertical side direction is in a symmetrical structure;

[0033] The first open-loop structure 5-1 and the second open-loop structure 5-2 are both in an "Ω" shape, and are composed of an open ring and an "L"-shaped branch spliced ​​at its two open ends. Figure 3 As shown; the open ring of the second open-loop structure 5-2 is also loaded with open branches, and the open branches are located in the middle position, and the ends of the "L"-shaped branches in the second open-loop structure 5-2 are linearly widened, such as Figure 4 As shown;

[0034] The first arc structure 5-3 and the second arc structure 5-4 adopt the same structure, which is composed of a first semicircular ring, a second semicircular ring, a third semicircular ring and a fourth semicircular ring of the same size spliced ​​in sequence. Figure 5 As shown; the centers of the first semicircular ring, the second semicircular ring, the third semicircular ring and the fourth semicircular ring are located on the same vertical edge, the first semicircular ring and the fourth semicircular ring are located on the same side of the vertical edge, and the second semicircular ring and the third semicircular ring are located on the other side of the vertical edge; the width of the second arc structure 5-4 is greater than the width of the first arc structure 5-3.

[0035] From the working principle: the present invention is as follows: Figure 6 On the basis of the traditional grid array antenna shown, the horizontal sides (short sides) are replaced by the first open-loop structure 5-1 and the second open-loop structure 5-2, which greatly reduces the axial ratio of the grid array antenna; the vertical sides (long sides) are replaced by the first arc structure 5-3 and the second arc structure 5-4, which greatly reduces the size of the grid array antenna; and the unique morphology design of the first open-loop structure, the second open-loop structure, the first arc structure and the second arc structure are matched, so that the grid packaged antenna can achieve excellent circular polarization performance and has the advantages of small packaging volume and low packaging cost; at the same time, the packaged antenna uses HDI process and chip for packaging to achieve high-density interconnection; it has good prospects for industrial application.

[0036] Furthermore, in this embodiment, the relative dielectric constant of the lower dielectric layer is 3.4 and the loss tangent is 0.01, the relative dielectric constant of the core layer is 3.55 and the loss tangent is 0.0027, and the relative dielectric constant of the upper dielectric layer is 3.4 and the loss tangent is 0.01. The opening angle (central angle) of the open ring in the first open-loop structure 5-1 and the second open-loop structure 5-2 is 58°; the width of the first open-loop structure 5-1 is 0.3mm, that is, the width of the open ring and the "L"-shaped branch is 0.3mm, and the circumference of the first open-loop structure is 5.4mm (half wavelength of 28GHz electromagnetic wave in free space), that is, the total length of the open ring and the "L"-shaped branch is 5.4mm; the width of the second open-loop structure 5-2 is 0.3mm, that is, the width of the open ring and the "L"-shaped branch is 0.3mm, and the circumference of the second open-loop structure is 5.4mm (half wavelength of 28GHz electromagnetic wave in free space), that is, the total length of the open ring and the "L"-shaped branch is 5.4mm (excluding open branches), and the width of the open branches in the second open-loop structure is 0.3mm and the length is 0.8mm. The width of the first arc structure 5-3 is 0.3mm, that is, the width of each semicircular ring is 0.3mm, and the circumference of the first arc structure is 10.8mm (the wavelength of 28GHz electromagnetic waves in free space); the width of the second arc structure 5-4 is 0.8mm, that is, the width of each semicircular ring is 0.8mm, and the circumference of the second arc structure is also 10.8mm. In addition, the end of the "L"-shaped branch in the second open-loop structure 5-2 is linearly widened to 0.8mm, and is spliced ​​with the second arc structure 5-4; in order to achieve 50Ω impedance matching of the input port, the inner diameter of the copper via 4 is 0.11mm, the outer diameter is 0.55mm, and the height is 3mm.

[0037] The electromagnetic field simulation software HFSS is used to simulate the circularly polarized grid package antenna. Figure 7 The figure shows the return loss of the grid package antenna. It can be seen from the figure that the S11 parameters of the antenna are all less than -10dB at 24.73GHz to 40GHz, almost covering the entire 5G millimeter wave frequency band. The relative bandwidth of the antenna can reach 47%, which has broadband characteristics. Figure 8 The figure shows the gain curve of the grid package antenna when the return loss is less than -10dB. The maximum gain can reach 6dBi and the minimum gain can reach 2.4dBi. Fig. 9 The figure shows the axial ratio curve of the grid package antenna when the return loss is less than -10dB. In the range of 24.6 to 36GHz, the axial ratio is less than 3dB, and the relative axial ratio reaches 37%, which reflects the excellent circular polarization performance.

[0038] The above description is only a specific implementation mode of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other alternative features that are equivalent or have similar purposes; all the disclosed features, or all the steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A circularly polarized grid package antenna based on HDI process, comprising: A lower dielectric layer (1), a core layer (2), an upper dielectric layer (3) and a grid array antenna (5) are stacked in sequence from bottom to top, wherein the grid array antenna (5) is connected to a signal end at the bottom of the lower dielectric layer through a copper via (4) passing through the upper dielectric layer, the core layer and the lower dielectric layer; characterized in that: The grid array antenna is composed of a central unit and side units spliced ​​on both sides thereof; the central unit is in a "sun"-shaped structure, consisting of two first open-loop structures (5-1), one second open-loop structure (5-2) and four first arc structures (5-3), wherein the second open-loop structure serves as a middle horizontal side, the first open-loop structure serves as two side horizontal sides, and the first arc structure serves as a vertical side; the side units are in an open structure, consisting of two second open-loop structures (5-2) and one second arc structure (5-4), wherein the second open-loop structure serves as a horizontal side, and the second arc structure serves as a vertical side; the open ends of the side units are respectively spliced ​​to the middle position of the first arc structure of the central unit; the grid array antenna is in a symmetrical structure along the center line of the vertical side direction; The first open-loop structure (5-1) and the second open-loop structure (5-2) are both in an "Ω" shape, and are composed of an open circular ring and an "L"-shaped branch spliced ​​at two open ends thereof; an open branch is also loaded inside the open circular ring of the second open-loop structure (5-2), and the open branch is located in the middle, and the end of the "L"-shaped branch in the second open-loop structure (5-2) is linearly widened; In the first open-loop structure (5-1) and the second open-loop structure (5-2), the opening angles of the open circular rings are the same, both being 58°; The first arc structure (5-3) and the second arc structure (5-4) adopt the same structure, and are respectively composed of a first semicircular ring, a second semicircular ring, a third semicircular ring and a fourth semicircular ring of the same size spliced ​​in sequence; the centers of the first semicircular ring, the second semicircular ring, the third semicircular ring and the fourth semicircular ring are located on the same vertical edge, the first semicircular ring and the fourth semicircular ring are located on the same side of the vertical edge, and the second semicircular ring and the third semicircular ring are located on the other side of the vertical edge.

2. The circularly polarized grid package antenna based on HDI process according to claim 1, characterized in that: The first open-loop structure (5-1) and the second open-loop structure (5-2) have the same circumference, which is half the wavelength of an electromagnetic wave of the operating frequency in free space.

3. The circularly polarized grid package antenna based on HDI process according to claim 1, characterized in that: The first open-loop structure (5-1) and the second open-loop structure (5-2) have the same width.

4. The circularly polarized grid package antenna based on HDI process according to claim 1, characterized in that: The width of the second arc-shaped structure (5-4) is greater than the width of the first arc-shaped structure (5-3).

5. The circularly polarized grid package antenna based on HDI process according to claim 1, characterized in that: The circumferences of the first arc-shaped structure (5-3) and the second arc-shaped structure (5-4) are the same, both being the wavelength of electromagnetic waves of the working frequency in free space.

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