Terahertz circularly polarized on-chip antenna with orbital angular momentum performance

Abstract

The application belongs to the field of antennas in wireless communication, and specifically provides a terahertz circularly polarized on-chip antenna with orbital angular momentum performance, which is used to realize the orbital angular momentum performance of the on-chip antenna in the terahertz frequency band, so that it can radiate a circularly polarized OAM beam with good performance, thereby improving the functionality and application range of the on-chip antenna, and proposing a new development direction of the on-chip antenna. The application adopts a degenerate mode separation technical means, and through grouping design of the octagonal ring patch and matching of the feed point, two separated degenerate modes with a phase difference of 90 degrees are excited on the octagonal ring patch, thereby producing a beam radiation with a spiral phase wave front structure, and finally realizing the orbital angular momentum performance. Application of the terahertz circularly polarized on-chip antenna with the orbital angular momentum performance in the communication field can effectively improve the channel capacity and spectrum efficiency, save valuable spectrum resources, and further expand the application range of the on-chip antenna.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of antennas in wireless communication, relates to on-chip antenna technology, and specifically provides a circularly polarized on-chip antenna with a half-mode SIW eight-edge ring patch structure and a dielectric resonator applied to a terahertz frequency band based on a 65nm CMOS process. BACKGROUND

[0002] With the development of wireless communication technology, the low-frequency spectrum has been largely occupied, and the requirement for data transmission rate in various fields is also increasingly high, so that the communication and radar industries have gradually shifted to the millimeter wave frequency band and even the terahertz frequency band with more abundant resources in recent years; among them, the terahertz wave has the characteristics of small energy, high spectral resolution and strong penetration ability, and has great development space in the fields of biomedicine (human chip), image shaping and nondestructive testing. At the same time, due to the extremely abundant spectrum resources of the terahertz frequency band, it will become the primary choice frequency band of the sixth generation of mobile communication standard (6G), and with the maturity and application of 5G technology, global operators and manufacturers have launched directional research and layout on 6G and corresponding terahertz technology. In addition, due to the extremely small wavelength of the terahertz wave, the size of the terahertz antenna will also be reduced, which is exactly in line with the application scenario of the on-chip antenna technology; in the terahertz frequency band, the small enough size of the on-chip antenna can greatly reduce the chip area occupied by the antenna, which is conducive to the integration of the antenna and the radio frequency front end, removes the impedance matching network and reduces the cost. At present, there have been researches and designs on integrating on-chip antennas inside circuits in the terahertz frequency band; therefore, the research on on-chip antenna technology is of great significance to the development of future communication fields.

[0003] For the scarce spectrum resources, in addition to developing to higher frequencies, it is also a direction to achieve a breakthrough in information transmission mode from the physical characteristics of electromagnetic waves, and the orbital angular momentum (OAM) technology is one of them. Unlike traditional channel multiplexing technology, the orbital angular momentum electromagnetic wave expression with a spiral phase front has a phase factor like e jlφ , and the OAM mode number l can be used as a modulation parameter of the carrier, and multiple signals can be modulated onto orthogonal OAM beams carrying different modes to realize independent channels with different OAM mode coding at the same frequency. In theory, since the orbital angular momentum can have infinite dimensions, a fixed carrier frequency can realize an infinite number of independent orbital angular momentum channels; therefore, if the OAM technology can be well developed, the spectrum utilization rate can be effectively improved, and greater channel capacity and spectrum efficiency can be obtained to meet the requirements of future high-speed communication networks. However, there is almost no research on the performance of orbital angular momentum on on-chip antennas in the industry and academia; based on this, the application provides a terahertz circularly polarized on-chip antenna with orbital angular momentum performance. SUMMARY

[0004] The application aims to provide a terahertz circularly polarized on-chip antenna with orbital angular momentum performance, to realize the orbital angular momentum performance of the on-chip antenna in the terahertz frequency band, to enable the on-chip antenna to radiate a circularly polarized OAM beam with good performance, to improve the functionality and application range of the on-chip antenna, and to provide a new development direction for the on-chip antenna.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0006] A terahertz circularly polarized on-chip antenna with orbital angular momentum performance, characterized in that it comprises a silicon substrate layer 1, a silicon dioxide layer 2 and an octagonal columnar dielectric resonator 3 which are sequentially stacked from bottom to top; the silicon dioxide layer 2 is sequentially separated from bottom to top into a ground metal layer 4, a feeding metal layer 5 and a radiation metal layer 6.

[0007] The feeding metal layer 5 is a metal feed line.

[0008] The radiation metal layer 6 adopts an octagonal ring antenna, comprising a co-planar waveguide structure 7, an octagonal ring patch 8 and an octagonal slot 9; the co-planar waveguide structure is composed of a middle metal strip and two symmetrically arranged ground strips on both sides of the middle metal strip, the ground strips are grounded through short-circuit metal vias, the middle metal strip is located above the metal feed line and connected to the metal feed line through a transmission metal via; the octagonal slot is arranged in the center of the octagonal ring patch, and a circle of short-circuit metal vias is arranged around the octagonal slot on the octagonal ring patch; the feeding point of the octagonal ring patch is connected to the metal feed line through a feeding metal via; the feeding signal is transmitted to the metal feed line through the co-planar waveguide structure, and then fed to the octagonal ring patch through the metal feed line, to excite two degenerate modes with a phase difference of 90° on the octagonal ring patch.

[0009] The octagonal columnar dielectric resonator 3 is located directly above the octagonal ring patch and completely covers the octagonal ring patch.

[0010] Further, the octagonal columnar dielectric resonator, the octagonal ring patch and the octagonal slot adopt the same octagonal structure, the octagonal structure is composed of 4 long sides and 4 short sides arranged in a spaced manner, and the ratio of the long side to the short side is in the range of 1:0.97 to 1:0.99.

[0011] Further, the size ratio of the octagonal columnar dielectric resonator, the octagonal ring patch and the octagonal slot is 1.1:1:0.2.

[0012] Further, the width of the middle metal strip of the co-planar waveguide structure 7 is greater than the metal feed line.

[0013] Further, the feed point of the octagonal ring patch is located at the electric field strength of two degenerate modes with a phase difference of 90°.

[0014] Based on the above technical solutions, the present application has the following advantages:

[0015] The present application provides a terahertz circularly polarized on-chip antenna with orbital angular momentum performance, which has a half-mode SIW structure and a dielectric resonator, adopts a degenerate mode separation technique, and through grouping design of the octagonal ring patch and matching of the feed point, two separated degenerate modes with a phase difference of 90° are excited on the octagonal ring patch, thereby generating a beam radiation with a spiral phase wavefront structure, and finally realizing the orbital angular momentum performance. Application of the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the communication field can effectively improve the channel capacity and spectral efficiency, save valuable spectrum resources, and further expand the application range of the on-chip antenna. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a cross-sectional structure schematic diagram of the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the present application.

[0017] Figure 2 It is a top view structure schematic diagram of the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the present application.

[0018] Figure 3 It is an octagonal structure schematic diagram related to the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the present application.

[0019] Figure 4 It is a reflection coefficient result graph of the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the embodiment of the present application.

[0020] Figure 5 It is a gain result graph of the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the embodiment of the present application.

[0021] Figure 6 It is a beam phase distribution graph of the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the embodiment of the present application.

[0022] Figure 7 It is an axial ratio result graph of the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and beneficial effects of the present application more clear, the present application will be further described in detail below with reference to the drawings and examples.

[0024] The embodiment provides a terahertz circularly polarized on-chip antenna with an orbital angular momentum performance applied to a terahertz frequency band, which is realized by using a 65nm CMOS process, and a structure thereof is as shown in the figure. Figure 1 The terahertz circularly polarized on-chip antenna with the orbital angular momentum performance comprises, from bottom to top, a silicon substrate layer 1, a silicon dioxide layer 2 and an octagonal columnar dielectric resonator 3; wherein a ground metal layer 4, a feeding metal layer 5 and a radiation metal layer 6 are arranged in the silicon dioxide layer 2; the radiation metal layer adopts an octagonal ring antenna, and specifically comprises a coplanar waveguide structure 7, an octagonal ring patch 8 and an octagonal slot 9.

[0025] Specifically,

[0026] The overall size of the terahertz circularly polarized on-chip antenna with the orbital angular momentum performance is 0.8mm*0.8mm;

[0027] The permittivity of the octagonal columnar dielectric resonator 3 is 6, and the height thereof is 350um; the octagonal columnar dielectric resonator is located directly above (center coincides with) the octagonal ring patch 8 and completely covers the octagonal ring patch 8; the main function of the octagonal columnar dielectric resonator is to guide the beam and reduce the beam angle deviation caused by the mutual coupling among the feeding metal layer 5, the coplanar waveguide structure 7 and the octagonal ring patch 8; at the same time, it can reduce the divergence of the OAM beam and increase the pointing performance; finally, it can also simulate the influence of the medium pasted above the chip in the packaging process of the chip and reduce the error of the test result in the later stage;

[0028] The ground metal layer 4 adopts the entire M1 metal layer, which can isolate the octagonal ring antenna from the silicon substrate layer 1 with high loss, thereby improving the antenna gain;

[0029] The radiation metal layer 6 adopts the M9 metal layer, wherein

[0030] The coplanar waveguide structure 7 is composed of a middle metal strip and ground strips symmetrically arranged on the left and right sides of the middle metal strip; the length of the ground strip is 120um, and the width thereof is 160um; the ground strip is connected with the ground metal layer through a short-circuit metal via (1), namely, the ground; the middle metal strip is located above the feed line (the center lines coincide) and has a width greater than that of the feed line; the length of the middle metal strip is 120um, and the width thereof is 34um; the coplanar waveguide structure 7 receives the feeding signal by adding a pad on the ground strip and the middle metal strip during the layout design and connecting with a GSG probe during the test;

[0031] The eight-edge ring patch 8 is an antenna radiation body, and the principle of mode perturbation is used to divide the eight edges into two groups (corresponding to the long edges and the short edges in the following text). By adjusting the length ratio of the two groups of edges, the two degenerate modes are separated and a phase difference of 90° is generated, and the two groups of edges correspond to one mode respectively. By exciting through a suitable feed point, the orbital angular momentum performance can be generated. The inside is an octagonal slot 9, and a circle of short-circuit metal vias is arranged around the slot. The octagonal slot 9 and the eight-edge ring patch 8 form a half-mode SIW structure, which is conducive to adjusting the patch surface current, thereby generating a better circularly polarized effect, and is also conducive to the generation of reconfigurable performance, such as the design of an octagonal or eight-edge ring patch structure in the octagonal slot 9, which can generate a multi-mode OAM beam in combination with the eight-edge ring patch 8.

[0032] The feed metal layer 5 adopts an M8 metal layer, specifically a feed line with a width of 28.2 um and a length of 300 um. One end of the feed line is connected to the middle metal strip of the CPW structure 7 through six transmission metal vias and receives the feed signal from the CPW structure. The other end of the feed line is connected to the eight-edge ring patch 8 through one feed metal via. It should be noted that the position of the feed point has a great influence on the OAM performance of the entire on-chip antenna. Since the OAM performance is generated by two degenerate modes with a phase difference of 90°, a suitable feed point needs to be selected to excite the two modes simultaneously. Therefore, the position of the feed point should be at the overlap region of the strong electric fields of the two modes. After optimization design, the transverse distance of the feed point from the center of the antenna is about 50 um, and the longitudinal distance should be about 108 um.

[0033] More specifically, the centers of the eight-edge cylindrical dielectric resonator 3, the eight-edge ring patch 8, and the octagonal slot 9 all coincide with the center of the entire on-chip antenna, and the same octagonal structure is adopted, as shown in Figure 3 The octagonal structure is composed of four long edges L and four short edges D arranged in a staggered manner, and the ratio of the long edges to the short edges is in the range of 1:0.97 to 1:0.99. After optimization, the long edge of the eight-edge ring patch 8 in this embodiment is 208.32 um, and the short edge is 204 um. The size ratio of the eight-edge cylindrical dielectric resonator 3, the eight-edge ring patch 8, and the octagonal slot 9 is 1.1:1:0.2, from which the lengths of all the octagonal structures can be calculated. In addition, the radius of the feed metal via is optimized to be 1.66 um, and the radius of the remaining metal vias can be arbitrarily selected under the condition of meeting the process rules, and in this embodiment, the radius is set to 2 um.

[0034] As shown in Figure 4The figure shows the reflection coefficient of the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the embodiment, and it can be seen from the figure that the -10dB bandwidth is from 274.4GHz to 275.2GHz, and the S11 is -26.4dB at the lowest point 274.65GHz; the bandwidth is composed of two close resonance points, respectively from two separate antenna degenerate modes, thereby generating OAM performance covering the entire bandwidth.

[0035] As shown in the figure, Figure 5 The figure shows the directional diagram of the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the embodiment, which shows the directional diagram of the on-chip antenna in the E plane and the H plane at 274.75GHz, and it can be seen that the E plane and the H plane are almost the same, indicating that the beam is relatively uniform, and then the maximum gain is 3.3dBi; the low point in the middle of the directional diagram separates the beam, forming a beam shape with low in the middle and high on both sides, which just verifies one of the characteristics of the OAM beam, that is, the phase singularity in the middle of the OAM beam, and the energy near it is extremely low.

[0036] As shown in the figure, Figure 6 The figure shows the beam phase distribution of the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the embodiment, which shows the beam phase distribution of the on-chip antenna at 274.75GHz, and the observation plane is located 2.4mm above the antenna and has a size of 2.8mm*2.8mm; it can be seen that the beam has a spiral phase distribution in the observation plane, and the middle is a phase singularity, which just verifies another characteristic of the OAM beam, that is, the rotating phase wavefront; it can be seen from the figure that one rotation is 360°, and it rotates counterclockwise, so the OAM mode l is -1.

[0037] As shown in the figure, Figure 7 The figure shows the axial ratio diagram of the terahertz circularly polarized on-chip antenna with orbital angular momentum performance in the embodiment, which shows the antenna axial ratio performance of the on-chip antenna at 274.75GHz, and it can be seen that the axial ratio performance near the phase singularity 0° is very poor, but it does not need to be concerned because the energy is extremely low; the 3dB axial ratio bandwidth is from -18.7° to -54.9° on the left and from 15.7° to 49.9° on the right, and there is a large circularly polarized beam bandwidth, which has good circularly polarized performance.

[0038] The above is only a specific embodiment of the present application, and any feature disclosed in the specification can be replaced by other equivalent or similar purpose alternative features unless specifically described; all features disclosed or steps in all methods or processes can be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A terahertz circularly polarized on-chip antenna with orbital angular momentum performance, characterized in that, include: A silicon substrate layer (1), a silicon dioxide layer (2), and an octagonal cylindrical dielectric resonator (3) are stacked sequentially from bottom to top; the silicon dioxide layer (2) is provided with a ground metal layer (4), a feed metal layer (5), and a radiation metal layer (6) sequentially from bottom to top; The feeding metal layer (5) is a metal feed line; The radiating metal layer (6) adopts an octagonal ring antenna, including: a coplanar waveguide structure (7), an octagonal ring patch (8), and an octagonal slot (9); the coplanar waveguide structure is composed of a central metal strip and grounding strips symmetrically arranged on both sides, the grounding strips are grounded through short-circuit metal vias respectively, the central metal strip is located above the metal feed line, and the two are connected through transmission metal vias; the octagonal slot is opened at the center of the octagonal ring patch, and a ring of short-circuit metal vias is arranged around the octagonal slot on the octagonal ring patch; the feed point of the octagonal ring patch is connected to the metal feed line through a feed metal via; the feed signal is transmitted from the coplanar waveguide structure to the metal feed line, and fed to the octagonal ring patch through the metal feed line, exciting two degenerate modes with a 90° phase difference on the octagonal ring patch; The octagonal cylindrical dielectric resonator (3) is located directly above the octagonal annular patch and completely covers the octagonal annular patch; The octagonal cylindrical dielectric resonator, the octagonal annular patch, and the octagonal slot adopt the same octagonal structure. The octagonal structure is formed by 4 long sides and 4 short sides arranged at intervals, and the ratio of the long side to the short side is in the range of 1:0.97 to 1:0.

99. The feed point of the octagonal annular patch is located at the electric field strength of two degenerate modes with a 90° phase difference.

2. The terahertz circularly polarized on-chip antenna with orbital angular momentum performance as described in claim 1, characterized in that, The size ratio of the octagonal cylindrical dielectric resonator, the octagonal annular patch, and the octagonal slot is 1.1:1:0.

2.

3. The terahertz circularly polarized on-chip antenna with orbital angular momentum performance as described in claim 1, characterized in that, The width of the middle metal strip in the coplanar waveguide structure is greater than that of the metal feed line.

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