Millimeter wave double-frequency broadband 1-bit electric scanning reflection unit

Abstract

The millimeter wave dual-frequency broadband 1-bit electric scanning reflection unit comprises a surface metal structure, a dielectric core plate layer and a back metal ground layer which are stacked from top to bottom, the surface metal structure comprises a main radiation patch, a radio frequency switch and a parasitic patch, the main radiation patch is connected with the back metal ground layer through a metalized through hole, and the parasitic patch is coupled with the main radiation patch through an interdigital structure; the electric scanning reflection unit realizes phase switching of response polarization by controlling the on-off state of the radio frequency switch, and the working frequency at least covers two millimeter wave typical frequencies. According to the invention, a wider frequency band is covered under the condition that the surface topological structure is kept unchanged. Through the improvement of the invention, the limitation of the narrow band of the traditional electric scanning unit is overcome, and more design schemes are provided for the electric scanning metasurface unit.

Description

Technical Field

[0001] The present invention relates to an electronically scanned reflectarray antenna technology, and in particular to a new ultra-wideband electronically scanned reflector unit covering the 5G millimeter wave frequency band. Background Art

[0002] With the continuous development of 5G and future 6G networks, reconfigurable intelligent metasurface (RIS) as a new type of wireless communication technology has become a research hotspot due to its adjustability, flexibility and low cost. One of the main ways to achieve RIS is through reconfigurable reflectarray antenna (RRA), because RRA has a simplified feeding system, compact planar structure and low production cost. The electronically scanned reconfigurable reflectarray antenna achieves beam scanning and beamforming by changing the reflection phase of each unit, and the regulation of the reflection phase is controlled by various active devices and materials, such as micro-electromechanical system MEMS technology, liquid crystal materials, varactor diodes and PIN diodes. The reflectarray designed with air-fed half-wavelength and sub-half-wavelength electromagnetic metasurface units can achieve high gain, broadband, low sidelobe, and beam scanning without the need to design a large and complex feeding phase shifting circuit, which has great advantages in improving the miniaturization design of antennas and reducing the design complexity. Compared with traditional mechanical rotating scanning antennas and the high-cost and complex phase-shifting channels used in traditional phased array antennas, the beam scanning function formed by controlling switches using digital systems such as FPGA and microprocessor MPU can not only better meet the needs of high-speed systems, but also greatly reduce the production cost. By loading various active devices on the reflective patch, the phase-shifting circuit is moved from the back end of the array to the front end of the array aperture. The electromagnetic metasurface unit thus formed can have the ability to more flexibly control electromagnetic waves without changing the surface structure, and has broad application prospects in wave absorption / reflection / transmission, polarization deflection / conversion, radar cross-section RCS reduction, beam reconstruction, and the formation of orbital angular momentum OAM vortex electromagnetic fields.

[0003] In recent years, with the pursuit of full spectrum, full coverage, and full application in 5G and 6G communication systems, the demand and use of spectrum have changed significantly. These systems require higher data rates, faster switching mechanisms, and wider working bandwidths. In order to meet these needs, 5G introduces higher frequency bands, especially millimeter wave bands, which provides abundant spectrum resources and significantly improves the capacity and transmission rate of the system. There are not many reports on RIS-related research work for the 5G millimeter wave band, and the reported RIS working bandwidth is relatively narrow, covering only one or two adjacent bands of the 5G millimeter wave band, which limits the scope of application and does not fully utilize the abundant millimeter wave spectrum resources. Therefore, the study of broadband electromagnetic metasurface unit structures that can cover multiple millimeter wave bands can reduce the demand for multiple independent antenna arrays and their control circuits, thereby significantly reducing the overall cost of the system, which has important application value. Summary of the invention

[0004] Technical problem: The purpose of the present invention is to provide a new ultra-wideband electronically scanned reflection unit structure covering multiple millimeter-wave frequency bands, and further improve the working bandwidth of the metasurface unit. Unlike traditional electronically scanned units, the unit size is less than half a wavelength by miniaturizing the antenna unit through a sub-wavelength design. At the same time, an interdigitated structure is introduced to replace the traditional coupling method between the main reflection surface and the parasitic patch, which effectively broadens the bandwidth of the antenna unit. The proposed unit covers a wider frequency band while keeping the surface topology unchanged. This solution does not increase the number of RF board layers, but only achieves this function by changing the topology of the PCB surface patch. Through the improvement of the present invention, the narrowband limitations of traditional electronically scanned units have been overcome, and more design schemes are provided for electronically scanned metasurface units.

[0005] Technical solution:

[0006] To achieve the above-mentioned purpose, the present invention provides a millimeter-wave dual-band broadband 1-bit electrically scanned reflection unit, comprising a surface metal structure, a dielectric core layer and a back metal stratum stacked from top to bottom; the surface metal structure comprises a main radiation patch, a radio frequency switch and a parasitic patch, the main radiation patch is connected to the back metal stratum through a metallized through-hole, and the parasitic patch is coupled to the main radiation patch through an interdigital structure; the electrically scanned reflection unit realizes phase switching of the response polarization by controlling the switching state of the radio frequency switch, and the operating frequency covers at least two typical millimeter-wave frequencies. The state of the radio frequency switch in the unit is defined as: 0 indicates that the switch is disconnected, and 1 indicates that the switch is on. The on and off of the switch can cause the corresponding co-polarized wave to produce a 180° reflection phase difference.

[0007] Furthermore, the surface metal structure includes a pair of main radiation patches, the two main radiation patches are of the same size and symmetrical shape, and are arranged in a mirror image around the center of the unit.

[0008] Furthermore, the slotted position at the center of the electric scanning reflection unit is the welding position of the radio frequency switch.

[0009] Furthermore, the opening position of the metallized through hole is on the symmetry axis of the main radiation patch, and each of the two main radiation patches has a metallized through hole connected to the back metal layer.

[0010] Furthermore, rectangular parasitic patches are respectively provided at four corners of the main radiation patch, and the parasitic patches are respectively coupled with the main radiation patch through an interdigital structure.

[0011] Furthermore, the feeder structure of the electric scanning reflection unit is located on the back of the dielectric core layer.

[0012] Furthermore, the electric scanning reflection unit is manufactured by using PCB technology.

[0013] Furthermore, the size of the electrically scanned reflection unit is smaller than half of its corresponding wavelength.

[0014] The present invention also provides a reconfigurable intelligent super surface, which is composed of the above-mentioned electric scanning reflection units.

[0015] Furthermore, the electric scanning reflection units are closely fitted to each other.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following beneficial effects: Compared with the prior art, the present invention provides an ultra-wideband electronically scanned reflection unit with the ability to cover multiple millimeter wave frequency bands. By improving the structure of the traditional reflection unit, the operating frequency band with a reflection phase response difference of 180° is further broadened, and it can be controlled by a programmable logic gate FPGA chip. The proposed antenna has a reasonable structure, meets the current processing technology, has excellent scalability, and has great application prospects in electronically scanned arrays. The solution has high engineering practicality and innovation, and meets the needs of various application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a structural stereogram of the ultra-wideband electronic scanning unit;

[0018] Figure 2 is a structural perspective view of the ultra-wideband electronic scanning unit;

[0019] Figure 3 is a top view of the structure of the ultra-wideband electronic scanning unit;

[0020] Figure 4 is a side view of the ultra-wideband electronic scanning unit;

[0021] Figure 5 is the amplitude response of the ultra-wideband electronic scanning unit in two states when it is working;

[0022] Figure 6 The phase response comparison of the ultra-wideband electronic scanning unit in two working states;

[0023] The numbers in the figure represent:

[0024] 1-Schematic diagram of the main radiation patch on the surface metal layer, 2-Metalized through-hole connecting the two poles of the RF switch and the metal layer, 3-Schematic diagram of the parasitic patches around the main radiation patch, 4-Dielectric core board layer, 5-Metal layer at the bottom of the unit. DETAILED DESCRIPTION

[0025] The above description and other technical features of the present invention are further described below in conjunction with the accompanying drawings.

[0026] This specific embodiment discloses a broadband electric scanning reflection unit that can be compactly arranged, such as Figures 1 to 4 As shown, Figure 1 is a structural stereogram of the ultra-wideband electronic scanning unit; Figure 2 is a structural perspective view of the ultra-wideband electronic scanning unit; Figure 3 is a top view of the structure of the ultra-wideband electronic scanning unit; Figure 4 A side view of the ultra-wideband electronic scanning unit.

[0027] The compactly arranged broadband electric scanning metasurface reflection unit of the present invention comprises a surface metal structure, a dielectric core plate layer and a back metal layer stacked from top to bottom. A pair of mirror-symmetrical main radiation patches on the surface are each provided with a slot of a certain length in the middle for placing a radio frequency switch.

[0028] Furthermore, firstly, a half-wavelength periodic structure of the unit is selected according to the highest frequency point in the working frequency band. In this embodiment, the periodic lengths of the unit in the x and y directions are the same, and a pair of vias on the axis of the main radiation patch are used to feed the RF switch in the center of the patch. It is worth pointing out that the patch shape and the corresponding via position and the number of PCB layers can be modified according to actual application requirements.

[0029] Example

[0030] In this embodiment, an ultra-wideband 1-bit reflective metasurface unit operating at 25-40 GHz is provided. The period length p of the unit in the x and y directions is set to 3.5 mm. The dielectric core board 4 adopts a Rogers RO4003C high-frequency board. The thickness of the upper and lower metal copper layers of the core board is 0.018 mm, and the diameter of the vias is 0.26 mm.

[0031] like Figure 1As shown, the copper-clad pattern on the surface of the upper dielectric core board is a pair of main radiation patches 1, both patches are connected to the metal layer 5 through the grounding via 2, and four parasitic patches 3 are loaded around the main radiation patch and are coupled to the main radiation patch 1 through the interdigital structure.

[0032] The 1-bit reflective metasurface unit of the implementation case is simulated and calculated by the Floquet port periodic boundary. The amplitude response of the 1-bit reflective metasurface unit when the RF switch is turned on and off is as follows: Figure 5 As shown, the phase response is Figure 6 It can be found that by using the unit structure proposed by the present invention, the unit achieves a phase response of two states with a phase difference of 180° within an ultra-wide frequency band.

[0033] The above description is only a preferred embodiment of the present invention, which is only illustrative and not restrictive. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements can be made, even equivalent, such as modifying the unit size or the number of layers and fine-tuning the patch, etc., but these improvements and modifications will be regarded as the protection scope of the present invention.

Claims

1. A millimeter wave dual-frequency broadband 1-bit electronically scanned reflection unit, characterized in that: It includes a surface metal structure, a dielectric core layer and a back metal stratum stacked from top to bottom; the surface metal structure includes a main radiation patch, a radio frequency switch and a parasitic patch, the main radiation patch is connected to the back metal stratum through a metallized through-hole, and the parasitic patch is coupled to the main radiation patch through an interdigital structure; the electric scanning reflection unit realizes phase switching of the response polarization by controlling the switching state of the radio frequency switch, and the operating frequency covers at least two typical millimeter wave frequencies.

2. The millimeter wave dual-band broadband 1-bit electronically scanned reflection unit according to claim 1, characterized in that: The surface metal structure includes a pair of main radiation patches, the two main radiation patches are of the same size and symmetrical in shape, and are arranged in a mirror image at the center of the unit.

3. The millimeter wave dual-frequency broadband 1-bit electronically scanned reflection unit according to claim 1, characterized in that: The slot at the center of the electric scanning reflection unit is the welding point of the RF switch.

4. The millimeter wave dual-frequency broadband 1-bit electronically scanned reflection unit according to claim 2, characterized in that: The opening position of the metallized through hole is on the symmetry axis of the main radiation patch, and each of the two main radiation patches has a metallized through hole connected to the back metal layer.

5. The millimeter wave dual-band broadband 1-bit electronically scanned reflection unit according to claim 1, characterized in that: The four corners of the main radiation patch are respectively provided with rectangular parasitic patches, and the parasitic patches are respectively coupled with the main radiation patch through an interdigital structure.

6. The millimeter wave dual-frequency broadband 1-bit electronically scanned reflection unit according to claim 1, characterized in that: The feeder structure of the electric scanning reflection unit is located at the back of the dielectric core layer.

7. The millimeter wave dual-band broadband 1-bit electronically scanned reflection unit according to claim 1, characterized in that: The electric scanning reflection unit is manufactured by adopting PCB technology.

8. The millimeter wave dual-frequency broadband 1-bit electronically scanned reflection unit according to claim 1, characterized in that: The size of the electrically scanned reflection unit is smaller than half of its corresponding wavelength.

9. A reconfigurable intelligent metasurface, characterized in that: It is composed of the electric scanning reflection unit described in any one of claims 1-8.

10. The reconfigurable intelligent metasurface according to claim 9, characterized in that: The electric scanning reflection units are closely fitted to each other.

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