Broadband vertical coupling transition structure based on liquid crystal material

Abstract

The invention provides a broadband vertical coupling transition structure based on a liquid crystal material, relates to the technical field of microwaves, and realizes cross-layer transmission of microwave signals in multilayer media including a liquid crystal layer by completing matching design and electromagnetic coupling between an upper strip line patch and a lower strip line patch through a square groove in a ground layer. Modeling simulation is carried out on the coupling transition structure in three-dimensional electromagnetic field simulation software, the simulation result shows that the overall insertion loss of the coupling transition structure is smaller than 3.7 dB, and the relative bandwidth reaches 100%.

Description

Technical Field

[0001] The invention relates to the field of microwave technology, in particular to a broadband vertical coupling transition structure based on liquid crystal material. Background Art

[0002] In a multilayer microwave device structure, such as a phase shifter based on liquid crystal materials, a vertical transition structure across the layers is usually essential.

[0003] Generally, there are three ways to achieve cross-layer vertical coupling. The first is through metal vias. The vertical microstrip transition based on metal vias has broadband characteristics, but when the frequency is too high, the metal vias will have serious parasitic effects, thereby deteriorating the system performance. The second is through a cavity transition structure. The circuit processing of the microstrip vertical transition structure based on cavity coupling is relatively complicated. The third is through a slotted coupling transition structure. The slotted coupling transition structure can achieve coupling without vias and is easy to process. However, the dielectric layers in the current cross-layer transition structure are mostly isotropic media, that is, fixed dielectric constant media, and there are few variable dielectric constant dielectric layers such as liquid crystals. Summary of the invention

[0004] In order to solve the above technical problems and realize vertical coupling across dielectric layers in the presence of a variable dielectric constant medium, the present invention provides a broadband vertical coupling transition structure based on liquid crystal materials, which realizes cross-layer transmission of microwave signals in multi-layer media including a liquid crystal layer, has the advantage of low loss, and can have a wider operating bandwidth.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is: A broadband vertical coupling transition structure based on liquid crystal material includes, from bottom to top, a lower floor, a lower dielectric substrate, a lower glass substrate, a lower coupling patch, a liquid crystal layer, a middle slotted floor, an upper glass substrate, an upper coupling patch, an upper dielectric substrate, and an upper floor; all of the above structures constitute a cross-layer vertical coupling transition structure based on a slotted floor under the condition of an inhomogeneous medium.

[0006] Furthermore, the liquid crystal of the liquid crystal layer is an anisotropic material, and its relative dielectric constant can be continuously changed with the change of bias voltage, and is between 2.46 and 3.57.

[0007] Furthermore, the upper floor is also provided with slots of the same size and position as the middle slotted floor, in order to reduce the insertion loss of the entire coupling transition structure.

[0008] Furthermore, a diamond patch is provided in the slotted position of the middle slotted floor, which is used to introduce a resonance point and broaden the working bandwidth of the coupling structure.

[0009] Furthermore, the lower coupling patch is located between the lower glass substrate and the liquid crystal layer, and the upper coupling patch is located between the upper glass substrate and the upper dielectric substrate.

[0010] Furthermore, the lower dielectric substrate and the upper dielectric substrate are made of different materials and have different thicknesses.

[0011] Furthermore, the lower glass substrate and the upper glass substrate have the same relative dielectric constant and thickness.

[0012] Furthermore, the lower coupling patch couples the input energy to the upper coupling patch through the middle slotted floor for output.

[0013] Furthermore, the patch parts of the lower layer coupling patch and the upper layer coupling patch have the same size.

[0014] Further, the width of the transmission line portion of the lower coupling patch is smaller than the width of the transmission line portion of the upper coupling patch.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention is based on the slotted floor and realizes a broadband cross-layer vertical coupling transition structure based on liquid crystal material. The structure can adapt to the variable dielectric constant characteristics of the liquid crystal layer in the multi-layer dielectric layer, has the advantages of low insertion loss and ultra-wide operating frequency band, and the overall insertion loss is less than 3.7dB. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0017] Figure 1 A schematic diagram of a three-dimensional structure of a broadband vertical coupling transition structure based on liquid crystal material according to an embodiment of the present invention; Figure 2 It is a front view schematic diagram of a broadband vertical coupling transition structure based on liquid crystal material according to an embodiment of the present invention; Figure 3 A schematic top view of a broadband vertical coupling transition structure based on liquid crystal material according to an embodiment of the present invention; Figure 4 Schematic diagram of S11 under different liquid crystal dielectric constants of the vertical coupling transition structure in an embodiment of the present invention; Figure 5 Schematic diagram of S21 under different liquid crystal dielectric constants of the vertical coupling transition structure in an embodiment of the present invention.

[0018] Among them, the figure markings are: lower dielectric substrate 1, lower glass substrate 2, liquid crystal layer 3, upper glass substrate 4, upper dielectric substrate 5, lower floor 6, middle slotted floor 7, upper floor 8, lower coupling patch 9, upper coupling patch 10. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The broadband vertical coupling transition structure based on liquid crystal material of the present invention can be regarded as a cross-layer transition structure based on slot coupling, which realizes the transition of the upper and lower layers of the signal by slotting on the common floor. This structure presents a bandpass characteristic and is commonly used in non-metallic via cross-layer transmission of microstrip lines or strip lines. In this design, since the transmission line is to be encapsulated on the inside of the glass plate and cannot be connected to a matching load, the structure can be regarded as a four-port coupler with two open ports. Slotting on the common floor can realize cross-layer transmission of energy, and the size and position of the slot also have a tuning effect. The key to expanding the bandwidth of this transition structure to achieve its ultra-wideband work is to design the impedance matching of the input and coupled output ports.

[0021] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings, but are not intended to limit the present invention.

[0022] like Figure 1-Figure 3 As shown, the broadband vertical coupling transition structure based on liquid crystal material of the present invention mainly includes a glass substrate, a dielectric substrate, a liquid crystal layer, a floor, and a coupling patch.

[0023] like Figure 2 As shown, the lower dielectric substrate 1, the lower glass substrate 2, and the liquid crystal layer 3 are located between the lower floor 6 and the middle slotted floor 7 from bottom to top, and the upper glass substrate 4 and the upper dielectric substrate 5 are located between the middle slotted floor 7 and the upper floor 8 from bottom to top.

[0024] Among them, the material of the lower dielectric substrate 1 is Rogers 3003, with a thickness of 1.01mm; the material of the upper dielectric substrate 5 is Rogers 4350, with a thickness of 0.762mm; the relative dielectric constant of the lower glass substrate 2 and the upper glass substrate 4 is 5.2, with a thickness of 0.3mm; the relative dielectric constant of the liquid crystal layer 3 is between 2.46 and 3.57, with a thickness of 0.1mm; like Figure 1 As shown, the lower coupling patch 9 is located between the lower glass substrate 2 and the liquid crystal layer 3, and the upper coupling patch 10 is located between the upper glass substrate 4 and the upper dielectric substrate 5. The lower coupling patch 9 couples the input energy to the upper coupling patch 10 through the middle slotted floor 7 for output. The patch part size of the lower coupling patch 9 and the upper coupling patch 10 is 2.4 mm 2.4mm, the transmission line widths of the lower coupling patch 9 and the upper coupling patch 10 are different to meet the impedance matching requirements. The transmission line width of the lower coupling patch 9 is 0.3mm, and the transmission line width of the upper coupling patch 10 is 0.8mm; the slot size of the metal middle slot floor 7 is 2.6mm 2.6mm, with a diamond patch in the center, which is used to introduce a resonance point and broaden the working bandwidth of the coupling structure. The diagonal size of the diamond patch is 1.4mm 1.4mm; like Figure 3 As shown, the upper floor panel 8 is also slotted in the same size and position as the middle slotted floor panel 7, in order to reduce the insertion loss of the entire coupling structure.

[0025] like Figure 4 As shown, it is a schematic diagram of S11 under different liquid crystal dielectric constants of the vertical coupling transition structure in an embodiment of the present invention, and the liquid crystal dielectric constants are 2.46, 2.83, 3.20, and 3.57; like Figure 5 As shown, it is a schematic diagram of S21 under different liquid crystal dielectric constants of the vertically coupled transition structure in an embodiment of the present invention. The liquid crystal dielectric constant takes values ​​of 2.46, 2.83, 3.20, and 3.57. Under different liquid crystal dielectric constants, the insertion loss of the transition structure is less than 3.7dB.

[0026] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A broadband vertical coupling transition structure based on liquid crystal material, characterized in that: From bottom to top, it includes a lower floor (6), a lower dielectric substrate (1), a lower glass substrate (2), a lower coupling patch (9), a liquid crystal layer (3), a middle slotted floor (7), an upper glass substrate (4), an upper coupling patch (10), an upper dielectric substrate (5), and an upper floor (8); all of the above structures constitute a cross-layer vertical coupling transition structure based on a slotted floor in the case of an inhomogeneous medium, and the signal is coupled to the upper coupling patch (10) through the lower coupling patch (9).

2. The broadband vertical coupling transition structure based on liquid crystal material according to claim 1, characterized in that: The liquid crystal of the liquid crystal layer (3) is an anisotropic material, and its relative dielectric constant can be continuously changed with the change of bias voltage, and is between 2.46 and 3.

57.

3. The broadband vertical coupling transition structure based on liquid crystal material according to claim 1, characterized in that: The upper floor (8) is also provided with slots of the same size and position as the middle slotted floor (7), with the purpose of reducing the insertion loss of the entire coupling transition structure.

4. The broadband vertical coupling transition structure based on liquid crystal material according to claim 1, characterized in that: A diamond patch is provided in the slotted position of the middle slotted floor (7) for introducing a resonance point and widening the working bandwidth of the coupling structure.

5. The broadband vertical coupling transition structure based on liquid crystal material according to claim 1, characterized in that: The lower coupling patch (9) is located between the lower glass substrate (2) and the liquid crystal layer (3), and the upper coupling patch (10) is located between the upper glass substrate (4) and the upper dielectric substrate (5).

6. The broadband vertical coupling transition structure based on liquid crystal material according to claim 1, characterized in that: The lower dielectric substrate (1) and the upper dielectric substrate (5) are made of different materials and have different thicknesses.

7. The broadband vertical coupling transition structure based on liquid crystal material according to claim 1, characterized in that: The lower glass substrate (2) and the upper glass substrate (4) have the same relative dielectric constant and thickness.

8. The broadband vertical coupling transition structure based on liquid crystal material according to claim 1, characterized in that: The lower layer coupling patch (9) couples input energy to the upper layer coupling patch (10) through the middle layer slotted floor (7) for output.

9. The broadband vertical coupling transition structure based on liquid crystal material according to claim 1, characterized in that: The patch parts of the lower layer coupling patch (9) and the upper layer coupling patch (10) have the same size.

10. The broadband vertical coupling transition structure based on liquid crystal material according to claim 1, characterized in that: The width of the transmission line portion of the lower coupling patch (9) is smaller than the width of the transmission line portion of the upper coupling patch (10).

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