Broadband liquid crystal array antenna structure

Abstract

The present invention provides a broadband liquid crystal array antenna structure having a wide beam scanning range. [Solution] The present invention provides a broadband liquid crystal array antenna structure having a unique structural design. The present invention provides a broadband liquid crystal array antenna structure comprising a first substrate layer, a second substrate layer, a third substrate layer, a first liquid crystal layer, a first surface unit, a second surface unit, a third surface unit, and a fourth surface unit. The first liquid crystal layer is laminated and connected between the second substrate layer and the third substrate layer. When a bias is applied to the first liquid crystal layer, the broadband liquid crystal array antenna structure performs beam scanning based on a first angular range.

Description

Technical Field

[0001] The present invention relates to an antenna array structure, and particularly to a wideband liquid crystal array antenna structure.

Background Art

[0002] At present, indoor positioning technology is mainly implemented using Bluetooth (registered trademark) systems, ZigBee systems, and microstrip antenna systems. Here, in conventional microstrip antenna systems, components such as Micro Electro Mechanical Systems (MEMs), phase shift diodes (PIN diodes), and varactor diodes are mainly used to control the scanning beam of the microstrip antenna structure.

[0003] However, the micro electro mechanical system and the phase shift diode can only adjust the beam direction of the microstrip antenna structure to a small number of specific directions, and the varactor diode can only achieve continuous scanning within a narrow scanning range. Therefore, current microstrip antenna systems have difficulty meeting the requirements of high-precision Ultra-Wide Band (UWB) indoor positioning.

Summary of Invention

Problems to be Solved by the Invention

[0004] In view of this, the present invention provides a wideband liquid crystal array antenna structure having a wide beam scanning range.

Means for Solving the Problems

[0005] Embodiments of the present invention provide a broadband liquid crystal array antenna structure comprising a first substrate layer, a second substrate layer, a third substrate layer, a first liquid crystal layer, a first surface unit, a second surface unit, a third surface unit, and a fourth surface unit. The first substrate layer has a first upper surface and a first lower surface. The second substrate layer has a second upper surface and a second lower surface. The third substrate layer has a third upper surface and a third lower surface. The first liquid crystal layer is laminated and connected between the second and third substrate layers. The first surface unit is located on the first upper surface. The second surface unit is located on the second upper surface. The third surface unit is located on the third upper surface. The fourth surface unit is located on the third lower surface. When a bias is applied to the first liquid crystal layer, the broadband liquid crystal array antenna structure performs beam scanning based on a first angular range.

[0006] In one embodiment of the present invention, the first surface unit includes a first large rectangular surface patch and four first small rectangular surface patches. The center point of the first large rectangular surface patch corresponds to the center point of the first liquid crystal layer. Two of the four first small rectangular surface patches are adjacent to the first side of the first large rectangular surface patch, and the other two of the four first small rectangular surface patches are adjacent to the second side of the first large rectangular surface patch. The first side faces the second side.

[0007] In one embodiment of the present invention, the second surface unit includes a second surface rectangular patch and two groups of parasitic patches. The center point of the second surface rectangular patch corresponds to the center point of the first liquid crystal layer. One of the groups of parasitic patches is adjacent to the first side of the second surface rectangular patch, and the other of the groups of parasitic patches is adjacent to the second side of the second surface rectangular patch. The first side faces the second side.

[0008] In one embodiment of the present invention, the second surface rectangular patch is the main radiating patch.

[0009] In one embodiment of the present invention, each group of parasitic patches includes a second surface large rectangular patch, a second surface small rectangular patch, and a second surface band-shaped patch. The second surface large rectangular patch and the second surface small rectangular patch are connected via the second surface band-shaped patch. The second surface large rectangular patch is adjacent to the second surface rectangular patch. The second surface small rectangular patch is connected to the edge of the second upper surface.

[0010] In one embodiment of the present invention, the third surface unit is a metal grounding layer.

[0011] In one embodiment of the present invention, the third surface unit includes a third surface rectangular patch. The third surface rectangular patch includes three third surface slots arranged sequentially along a first direction, and furthermore, the center point of the second of the three third surface slots corresponds to the center point of the first liquid crystal layer.

[0012] In one embodiment of the present invention, the third surface slot is an H-shaped slot. The H-shape of the third surface slot extends along the second direction. The first direction is opposite to the second direction.

[0013] In one embodiment of the present invention, the fourth surface unit is a fourth surface strip patch. The fourth surface strip patch extends along a second direction and further corresponds to the center point of the first liquid crystal layer.

[0014] In one embodiment of the present invention, the fourth surface strip patch is a signal transmission line.

[0015] In one embodiment of the present invention, the fourth surface strip-shaped patch is a microstrip line.

[0016] In one embodiment of the present invention, the first surface unit, the second surface unit, the third surface unit, and the fourth surface unit are all made of a metallic material.

[0017] In one embodiment of the present invention, the first angular range is determined by the material of the first liquid crystal layer.

[0018] In one embodiment of the present invention, the first angular range is from -42 degrees to 42 degrees.

[0019] In one embodiment of the present invention, the first angular range is from -52 degrees to 52 degrees. [Advantageous Effects of the Invention]

[0020] Based on the above, the broadband liquid crystal array antenna structure of the present invention can provide a wide beam scanning range through its special structural design. [Brief Description of the Drawings]

[0021] [Figure 1A] The schematic diagram of the multilayer structure showing the broadband liquid crystal array antenna structure according to one embodiment of the present invention is presented. [Figure 1B] The cross-sectional view of the broadband liquid crystal array antenna structure according to one embodiment of the present invention is presented. [Figure 2A] The schematic diagram of the cell design of the first surface unit according to one embodiment of the present invention is presented. [Figure 2B] The schematic diagram of the cell design of the second surface unit according to one embodiment of the present invention is presented. [Figure 2C] The schematic diagram of the cell design of the third surface unit according to one embodiment of the present invention is presented. [Figure 2D] The schematic diagram of the cell design of the fourth surface unit according to one embodiment of the present invention is presented. [Figure 3A] The diagram showing the relationship between return loss and signal frequency of the broadband liquid crystal array antenna structure according to the first embodiment of the present invention is presented. [Figure 3B] The radiation pattern diagram of the broadband liquid crystal array antenna structure according to the first embodiment of the present invention is presented. [Figure 4A] The diagram showing the relationship between return loss and signal frequency of the broadband liquid crystal array antenna structure according to the second embodiment of the present invention is presented. [Figure 4B] The radiation pattern diagram of the broadband liquid crystal array antenna structure according to the second embodiment of the present invention is presented. [Figure 5A]This diagram shows the relationship between return loss and signal frequency for a broadband liquid crystal array antenna structure according to a third embodiment of the present invention. [Figure 5B] This shows a radiation pattern diagram of a broadband liquid crystal array antenna structure according to a third embodiment of the present invention. [Modes for carrying out the invention]

[0022] Hereinafter, exemplary embodiments of the present invention shown in the attached drawings will be described in detail. In the drawings and description, identical or similar components are denoted by the same reference numerals whenever possible.

[0023] Figure 1A shows a schematic diagram of the multilayer structure of a broadband liquid crystal array antenna structure according to one embodiment of the present invention. Figure 1B shows a cross-sectional view of the broadband liquid crystal array antenna structure according to one embodiment of the present invention. Referring to Figures 1A and 1B, the broadband liquid crystal array antenna structure is mainly designed as a 3-layer, 4-face circuit board. The broadband liquid crystal array antenna structure includes a first substrate layer 1, a second substrate layer 2, a third substrate layer 3, a first surface unit 4, a second surface unit 5, a third surface unit 6, a fourth surface unit 7, and a first liquid crystal layer 8. The first substrate layer 1 has a first upper surface 11 and a first lower surface 12. The second substrate layer 2 has a second upper surface 21 and a second lower surface 22. The third substrate layer 3 has a third upper surface 31 and a third lower surface 32.

[0024] The first liquid crystal layer 8 is laminated and connected between the second substrate layer 2 and the third substrate layer 3. The first surface unit 4 is located on the first upper surface 11. The second surface unit 5 is located on the second upper surface 21. The third surface unit 6 is located on the third upper surface 31. The fourth surface unit 7 is located on the third lower surface 32. The first substrate layer 1, the second substrate layer 2, the third substrate layer 3, and the third surface unit 6 each have four circular slots. Here, the four circular slots are located adjacent to and corresponding to two short sides of the first substrate layer 1, the second substrate layer 2, the third substrate layer 3, and the third surface unit 6, and the four circular slots of the first substrate layer 1, the second substrate layer 2, the third substrate layer 3, and the third surface unit 6 correspond to each other.

[0025] The first substrate layer 1, the second substrate layer 2, and the third substrate layer 3 may be, for example, double-sided high-frequency printed circuit boards. The substrate material used for the first substrate layer 1, the second substrate layer 2, and the third substrate layer 3 may be, for example, Rogers RO4533. In one embodiment, the dielectric constant of the first substrate layer 1, the second substrate layer 2, and the third substrate layer 3 may be, for example, 3.0 to 4.0 (optimal loss tangent is 3.45), the loss tangent may be, for example, 0.002 to 0.003 (optimal loss tangent is 0.0025), and the thickness may be, for example, 0.50 to 0.51 mm (optimal thickness is 0.508 mm).

[0026] The first surface unit 4, the second surface unit 5, the third surface unit 6, and the fourth surface unit 7 may be made of, for example, a metallic material (e.g., a metallic conductor such as copper foil or gold foil, or another metallic oxide conductor such as indium tin oxide). The copper foil thickness of the first surface unit 4, the second surface unit 5, the third surface unit 6, and the fourth surface unit 7 may be, for example, 0.035 mm. The third surface unit 6 is a metallic ground layer.

[0027] The liquid crystal material used in the first liquid crystal layer 8 may be, for example, JNC ZOC-A018XX, MERCK E7, or MERCK GT7-29001, and its thickness is 0.1 mm. The dielectric properties of the first liquid crystal layer 8 can be adjusted. When an external voltage is applied to the first liquid crystal layer 8, the rotation of its liquid crystal molecules changes, thereby changing its dielectric constant and loss tangent.

[0028] Taking JNC ZOC-A018XX as an example, the dielectric constant and loss tangent of the first liquid crystal layer 8 are 2.55 to 3.76 and 0.004 to 0.007, respectively. When a bias is applied to the first liquid crystal layer 8, the liquid crystal orientation direction of the first liquid crystal layer 8 becomes parallel to the electric field direction, and furthermore, the dielectric constant of the first liquid crystal layer 8 becomes 3.76 and the loss tangent becomes 0.004. On the other hand, when no bias voltage is applied to the first liquid crystal layer 8, the liquid crystal orientation direction of the first liquid crystal layer 8 becomes perpendicular to the electric field direction, the dielectric constant becomes 2.55 and the loss tangent becomes 0.007.

[0029] Taking the MERCK E7 as an example, the dielectric constant and loss tangent of the first liquid crystal layer 8 are 2.72 to 3.17 and 0.033 to 0.05, respectively. When a bias is applied to the first liquid crystal layer 8, the liquid crystal orientation direction of the first liquid crystal layer 8 becomes parallel to the electric field direction, and furthermore, the dielectric constant of the first liquid crystal layer 8 becomes 3.17 and the loss tangent becomes 0.033. On the other hand, when no bias voltage is applied to the first liquid crystal layer 8, the liquid crystal orientation direction of the first liquid crystal layer 8 becomes perpendicular to the electric field direction, the dielectric constant becomes 2.72 and the loss tangent becomes 0.05.

[0030] Taking the MERCK GT7-29001 as an example, the dielectric constant and loss tangent of the first liquid crystal layer 8 are 2.46 to 3.53 and 0.0064 to 0.0116, respectively. When a bias is applied to the first liquid crystal layer 8, the liquid crystal orientation direction of the first liquid crystal layer 8 becomes parallel to the electric field direction, and furthermore, the dielectric constant of the first liquid crystal layer 8 becomes 3.53 and the loss tangent becomes 0.0064. On the other hand, when no bias voltage is applied to the first liquid crystal layer 8, the liquid crystal orientation direction of the first liquid crystal layer 8 becomes perpendicular to the electric field direction, the dielectric constant becomes 2.46, and furthermore, the loss tangent becomes 0.0116.

[0031] To facilitate understanding, the properties of various liquid crystal materials are summarized in Table 1. [Table 1]

[0032] The dielectric properties of the first liquid crystal layer 8 change in response to the electric field, which in turn changes the beam characteristics of the liquid crystal array antenna structure. More specifically, when no bias voltage is applied to the first liquid crystal layer 8, the orientation of the liquid crystal molecules within the first liquid crystal layer 8 becomes parallel to the metal patch (i.e., the second surface unit 5) and the metal ground layer (i.e., the third surface unit 6), and the liquid crystal molecules become perpendicular to the direction of the electric field; this is called the perpendicular state. When a bias is applied to the first liquid crystal layer 8, the orientation of the liquid crystal molecules within the first liquid crystal layer 8 becomes perpendicular to the metal patch and the metal ground layer, and the liquid crystal molecules become parallel to the direction of the electric field; this is called the parallel state.

[0033] The types of the first substrate layer 1, the second substrate layer 2, the third substrate layer 3, and the first liquid crystal layer 8 can be designed according to actual requirements, and the present invention is not limited thereto.

[0034] Figure 2A shows a schematic diagram of the cell design of the first surface unit according to one embodiment of the present invention. Referring to Figure 2A, the first surface unit 4 is located on the first upper surface 11. The existing metal layer on the first upper surface 11 (for example, a copper foil with a thickness of 0.035 mm) is etched to form the first surface unit 4.

[0035] The first surface unit 4 includes a first surface large rectangular patch 41 and four first surface small rectangular patches 421 to 424. The center point of the first surface large rectangular patch 41 corresponds to the center point of the first liquid crystal layer 8. Two first surface small rectangular patches 421 and 422 are adjacent to one side (also called the first side) of the first surface large rectangular patch 41, and two other first surface small rectangular patches 423 and 424 are adjacent to the other side (also called the second side) of the first surface large rectangular patch 41. The first side is opposite to the second side. In other words, the first side is on the opposite side of the second side.

[0036] The width and length of the first upper surface 11 are indicated by A1 and A2 in Figure 2A, respectively. The distance between a circular slot on the first upper surface 11 (first substrate layer 1) and a corresponding circular slot on the other side is B1, and the distance between it and a corresponding circular slot on the same side is B2.

[0037] The width and length of the large rectangular patch 41 on the first surface are indicated by C1 and C2 in Figure 2A, respectively. The width and length of the small rectangular patches 421 to 424 on the first surface are indicated by D1 and D2 in Figure 2A, respectively.

[0038] In one embodiment, the width and length of the first upper surface 11 (indicated as A1 and A2 in Figure 2A) may be, for example, 43.50 to 44.50 mm (optimal width is 44.00 mm) and 17.50 to 18.50 mm (optimal length is 18.00 mm), respectively.

[0039] Furthermore, regarding the specifications of the first surface unit 4, the distance between the circular slot on the first upper surface 11 (first substrate layer 1) and the corresponding circular slot on the other side (shown as B1 in Figure 2A) may be, for example, 40.00 to 40.10 mm (optimal width is 40.00 mm), and the distance between the circular slot on the first upper surface 11 (first substrate layer 1) and the corresponding circular slot on the same side (shown as B2 in Figure 2A) may be, for example, 12.00 to 12.10 mm (optimal width is 12.00 mm), and The width and length of the large rectangular patch 41 on the first surface (indicated by C1 and C2 in Figure 2A) may be, for example, 7.49 to 7.51 mm (optimal width is 7.50 mm) and 8.49 to 8.51 mm (optimal length is 8.50 mm), respectively, and the width and length of the small rectangular patches 421 to 424 on the first surface (indicated by D1 and D2 in Figure 2A) may be, for example, 0.99 to 1.01 mm (optimal width is 1.00 mm) and 0.99 to 1.01 mm (optimal length is 1.00 mm), respectively.

[0040] Figure 2B shows a schematic diagram of the cell design of the second surface unit according to one embodiment of the present invention. Referring to Figure 2B, the second surface unit 5 is located on the second upper surface 21. The existing metal layer on the second upper surface 21 (for example, a copper foil with a thickness of 0.035 mm) is etched to form the second surface unit 5.

[0041] The second surface unit 5 includes a second surface rectangular patch 51 and two parasitic patch groups 52 and 53. The center point of the second surface rectangular patch 51 corresponds to the center point of the first liquid crystal layer 8, and furthermore, the second surface rectangular patch 51 is the main radiating patch. Parasitic patch group 52 is adjacent to one side (also called the first side) of the second surface rectangular patch 51, and parasitic patch group 53 is adjacent to the other side (also called the second side) of the second surface rectangular patch 51. The first side faces the second side. In other words, the first side is on the opposite side of the second side.

[0042] The parasitic patch group 52 includes a second surface large rectangular patch 521, a second surface small rectangular patch 522, and a second surface band-shaped patch 523. The second surface large rectangular patch 521 and the second surface small rectangular patch 522 are connected via the second surface band-shaped patch 523. Similarly, the parasitic patch group 53 includes a second surface large rectangular patch 531, a second surface small rectangular patch 532, and a second surface band-shaped patch 533. The second surface large rectangular patch 531 and the second surface small rectangular patch 532 are connected via the second surface band-shaped patch 533.

[0043] The large rectangular patches 521 and 531 on the second surface are adjacent to the rectangular patch 51 on the second surface. The small rectangular patches 522 and 532 on the second surface are connected to the edges of the second upper surface 21.

[0044] The width and length of the second upper surface 21 are indicated by A1 and A2 in Figure 2B, respectively.

[0045] The width and length of the second surface rectangular patch 51 are indicated by B1 and B2 in Figure 2B, respectively. The width and length of the second surface large rectangular patches 521 and 531 are indicated by C1 and C2 in Figure 2B, respectively. The width and length of the second surface small rectangular patches 522 and 532 are indicated by D1 and D2 in Figure 2B, respectively. The width and length of the second surface band-shaped patches 523 and 533 are indicated by E1 and E2 in Figure 2B, respectively. The distance between the second surface large rectangular patches 521 and 531 and the second surface rectangular patch 51 is indicated by d in Figure 2B.

[0046] In one embodiment, the width and length of the second upper surface 21 (indicated as A1 and A2 in Figure 2B) may be, for example, 49.50 to 50.50 mm (optimal width is 50.00 mm) and 17.50 to 18.50 mm (optimal length is 18.00 mm), respectively.

[0047] Furthermore, regarding the specifications of the second surface unit 5, the width and length of the second surface rectangular patch 51 (shown as B1 and B2 in Figure 2B) may be, for example, 18.99~19.01 mm (optimal width is 19.00 mm) and 8.99~9.01 mm (optimal length is 9.00 mm), respectively, and the width and length of the second surface large rectangular patches 521 and 531 (shown as C1 and C2 in Figure 2B) may be, for example, 8.09~8.11 mm (optimal width is 8.10 mm) and 8.09~8.11 mm (optimal length is 8.10 mm), respectively, and the width and length of the second surface small rectangular patches 522 and 532 (shown as D1 and The dimensions of the second surface strip patches 523 and 533 (shown as E1 and E2 in Figure 2B) may be, for example, 2.99 to 3.01 mm (optimal width is 3.00 mm) and 2.99 to 3.01 mm (optimal length is 3.00 mm), respectively, and the width and length of the second surface strip patches 523 and 533 (shown as E1 and E2 in Figure 2B) may be, for example, 3.89 to 3.91 mm (optimal width is 3.90 mm) and 0.99 to 1.10 mm (optimal length is 1.00 mm), respectively, and the distance between the second surface large rectangular patches 521 and 531 and the second surface rectangular patch 51 (shown as d in Figure 2B) may be, for example, 0.49 to 0.51 mm (optimal length is 0.50 mm).

[0048] Figure 2C shows a schematic diagram of the cell design of the third surface unit according to one embodiment of the present invention. Referring to Figure 2C, the third surface unit 6 is located on the third upper surface 31. The existing metal layer on the third upper surface 31 (for example, a copper foil with a thickness of 0.035 mm) is etched to form the third surface unit 6. Here, the third surface unit 6 is a metal ground layer. The first liquid crystal layer 8 is also laminated on the third surface unit 6 and is therefore shown together in Figure 2C.

[0049] The third surface unit 6 includes a third surface rectangular patch 61. The third surface rectangular patch 61 includes three third surface slots 621-623 arranged sequentially along the X-axis (also called the first direction), and the center point of the second third surface slot 622 corresponds to the center point of the first liquid crystal layer 8. The third surface slots 621-623 are, for example, H-shaped slots. The H-shape of the H-shaped slots (i.e., the third surface slots 621-623) extends along the Y-axis (also called the second direction). The first direction is different from the second direction.

[0050] The dimensions of the third upper surface 31 and the third surface rectangular patch 61 are identical. That is, the width and length of the third upper surface 31 and the width and length of the third surface rectangular patch 61 are identical. The width and length of the third upper surface 31 (third surface rectangular patch 61) are shown as A1 and A2, respectively, in Figure 2C.

[0051] The width and length of the first liquid crystal layer 8 are indicated by B1 and B2, respectively, in Figure 2C.

[0052] In one embodiment, the width and length of the third upper surface 31 (indicated as A1 and A2 in Figure 2C) may be, for example, 49.50 to 50.50 mm (optimal width is 50.00 mm) and 19.50 to 20.50 mm (optimal length is 20.00 mm), respectively.

[0053] Furthermore, the width and length of the first liquid crystal layer 8 (shown as B1 and B2 in Figure 2C) may be, for example, 40.00 to 40.10 mm (optimal width is 40.05 mm) and 10.00 to 10.10 mm (optimal length is 10.05 mm), respectively.

[0054] Furthermore, regarding the specifications of the third surface unit 6, the specifications of the third surface slots 621 to 623 are all the same. Taking the third surface slot 622 as an example, the lengths indicated by C1, C2, C3, and C4 in Figure 2C are, for example, 3.64 to 3.66 mm (optimal length is 3.65 mm), 3.99 to less than 4.01 mm (optimal length is 4.00 mm), 0.24 to 0.26 mm (optimal length is 0.25 mm), and 1.99 to 2.01 mm (optimal length is 2.00 mm), respectively. As shown in Figure 2C, the lengths on both sides of the H-shaped slot (i.e., the third surface slot 622) are equal.

[0055] Figure 2D shows a schematic diagram of the cell design of the fourth surface unit according to one embodiment of the present invention. Referring to Figure 2D, the fourth surface unit 7 is located on the third lower surface 32. The existing metal layer on the third lower surface 32 (for example, a copper foil with a thickness of 0.035 mm) is etched to form the fourth surface unit 7.

[0056] The fourth surface unit 7 is a fourth surface strip-shaped patch. Specifically, the fourth surface unit 7 may be, for example, a microstrip line. The fourth surface strip-shaped patch 7 extends along the Y-axis (also called the second direction), and furthermore, the fourth surface strip-shaped patch 7 corresponds to the center point of the first liquid crystal layer 8.

[0057] The dimensions of the third lower surface 32 and the third upper surface 31 are identical. The width and length of the third lower surface 32 are indicated by A1 and A2, respectively, in Figure 2D.

[0058] The width and length of the fourth surface unit 7 are indicated by B1 and B2, respectively, in Figure 2D.

[0059] In one embodiment, the width and length of the third lower surface 32 (indicated as A1 and A2 in Figure 2D) may be, for example, 49.50 to 50.50 mm (optimal width is 50.00 mm) and 19.50 to 20.50 mm (optimal length is 20.00 mm), respectively.

[0060] Furthermore, the width and length of the fourth surface unit 7 (shown as B1 and B2 in Figure 2D) may be, for example, 0.99 to 1.01 mm (optimal width is 1.00 mm) and 16.09 to 16.11 mm (optimal length is 16.10 mm), respectively.

[0061] Referring to Figures 1A to 2D simultaneously, the center point of the second surface rectangular patch 51 and the center point of the third surface slot 622 correspond to the center point of the first liquid crystal layer 8, and furthermore, the fourth surface strip-shaped patch 7 corresponds to the first liquid crystal layer 8.

[0062] The third surface rectangular patch 61 is a metal grounding layer, and the fourth surface strip patch 7 is a microstrip wire. The fourth surface strip patch 7 can be used, for example, as a signal feed line, and the third surface rectangular patch 61 can be used, for example, as a grounding layer for the fourth surface strip patch 7.

[0063] To further explain, the first liquid crystal layer 8 is positioned between the second substrate layer 2 and the third substrate layer 3, and both the second substrate layer 2 and the third substrate layer 3 have a metallic structure. Specifically, the second upper surface 21 has a second surface rectangular patch 51, and the third upper surface 31 and the third lower surface 32 have a third surface rectangular patch 61 and a fourth surface strip-shaped patch 7, respectively, which have a metallic structure. When a signal is coupled and powered from the fourth surface strip-shaped patch 7 to the broadband liquid crystal array antenna structure, a voltage difference is generated between the fourth surface strip-shaped patch 7 and the second surface rectangular patch 51, thereby applying a bias to the first liquid crystal layer 2 and controlling the beam scanning function of the broadband liquid crystal array antenna structure.

[0064] Furthermore, in order to apply a bias to the first liquid crystal layer 8, the four peripheral edges of the second substrate layer 2 and the third substrate layer 3 are all designed as metal edges. This is a common technical means well known to those skilled in the art, and therefore the four peripheral edges of the second substrate layer 2 are not specifically indicated as metal edges in the drawings. The third surface slots 621 and 623 correspond to the second surface large rectangular patches 521 and 531, respectively, and the second surface small rectangular patches 522 and 532 are connected to the edges of the second base plate 2. Therefore, when a signal is coupled and fed to the broadband liquid crystal array antenna structure from the fourth surface strip-shaped patch 7, resonance occurs between the parasitic patch groups 52 and 53, which are not directly connected to the power supply (i.e., the fourth surface strip-shaped patch 7), and the second surface rectangular patch 51 (i.e., the main radiating patch) due to coupling. This expands the bandwidth of the broadband liquid crystal array antenna structure and realizes the function of controlling the beam scanning direction.

[0065] Figure 3A shows the relationship between return loss and signal frequency for a broadband liquid crystal array antenna structure according to the first embodiment of the present invention. Figure 3B shows the radiation pattern diagram for the broadband liquid crystal array antenna structure according to the first embodiment of the present invention. Here, the S11 parameter is also called the input reflection coefficient and is used to indicate the return loss at the signal transmission end. The return loss is used to express the absolute value of the S11 parameter, and its unit is decibels (dB).

[0066] Referring to Figures 3A and 3B, in this embodiment, the liquid crystal material used in the first liquid crystal unit 8 is JNC ZOC-A018XX.

[0067] The unbiased values ​​in Figures 3A and 3B are used to represent the S11 parameters of the broadband liquid crystal array antenna structure when no power is applied (i.e., when no bias is applied to the first liquid crystal layer 8). When no bias voltage is applied to the first liquid crystal layer 8, the center operating frequency of the broadband liquid crystal array antenna structure is 7.08 to 7.62 GHz with -10 dB as the reference point, the bandwidth is 0.54 GHz, and the bandwidth ratio is 7.2%. Also, when no bias voltage is applied to the first liquid crystal layer 8, the maximum gain at a reflection angle of 0 degrees is 6.94 dBi.

[0068] The first parasitic patch group in Figures 3A and 3B is used to represent the S11 parameter of the broadband liquid crystal array antenna structure after energizing the first parasitic patch group (i.e., parasitic patch group 52). More specifically, in this embodiment, a 20-volt square wave is generated by a signal generator (not shown) and supplied to the parasitic patch group 52 of the second surface unit 5 and the third surface rectangular patch 61 (i.e., the metal ground surface) of the third surface unit 6. When a bias is applied to the parasitic patch group 52, the center operating frequency of the broadband liquid crystal array antenna structure becomes 7.07 to 7.58 GHz with -10 dB as the reference point, the bandwidth becomes 0.51 GHz, and the bandwidth ratio becomes 6.8%. Also, when a bias is applied to the parasitic patch group 52, the maximum gain at a reflection angle of 42 degrees becomes 6.53 dBi.

[0069] The second parasitic patch group in Figures 3A and 3B is used to indicate the S11 parameter of the broadband liquid crystal array antenna structure after energizing the second parasitic patch group (i.e., parasitic patch group 53). More specifically, in this embodiment, a 20-volt square wave is generated by a signal generator and supplied to the parasitic patch group 53 of the second surface unit 5 and the third surface rectangular patch 61 (i.e., the metal ground surface) of the third surface unit 6. When a bias is applied to the parasitic patch group 53, the center operating frequency of the broadband liquid crystal array antenna structure becomes 7.07 to 7.58 GHz with -10 dB as the reference point, the bandwidth becomes 0.50 GHz, and the bandwidth ratio becomes 6.8%. When a bias is applied to the parasitic patch group 53, the maximum gain is 6.57 dBi at a reflection angle of -42 degrees.

[0070] Figure 4A shows a diagram illustrating the relationship between return loss and signal frequency in a broadband liquid crystal array antenna structure according to a second embodiment of the present invention. Figure 4B shows a radiation pattern diagram of the broadband liquid crystal array antenna structure according to a second embodiment of the present invention. Referring to Figures 4A and 4B, the liquid crystal material used in the first liquid crystal layer 8 in this embodiment is MERCK E7.

[0071] As shown in Figures 4A and 4B, when no bias voltage is applied to the first liquid crystal layer 8, the center operating frequency of the broadband liquid crystal array antenna structure is 7.04 to 7.61 GHz with -10 dB as the reference point, the bandwidth is 0.57 GHz, and the bandwidth ratio is 7.26%. Also, when no bias voltage is applied to the first liquid crystal layer 8, the maximum gain at a reflection angle of 0 degrees is 3.94 dBi.

[0072] As shown in Figures 4A and 4B, when a bias is applied to the parasitic patch group 52, the center operating frequency of the broadband liquid crystal array antenna structure becomes 7.03 to 7.58 GHz with -10 dB as the reference point, the bandwidth becomes 0.55 GHz, and the bandwidth ratio becomes 7.30%. Furthermore, when a bias is applied to the parasitic patch group 52, the maximum gain at a reflection angle of 52 degrees is 4.26 dBi.

[0073] As shown in Figures 4A and 4B, when a bias is applied to the parasitic patch group 53, the center operating frequency of the broadband liquid crystal array antenna structure becomes 7.04 to 7.58 GHz with -10 dB as the reference point, the bandwidth becomes 0.54 GHz, and the bandwidth ratio becomes 7.20%. Furthermore, when a bias is applied to the parasitic patch group 53, the maximum gain at a reflection angle of 52 degrees is 4.26 dBi.

[0074] Figure 5A shows a diagram illustrating the relationship between return loss and signal frequency in a broadband liquid crystal array antenna structure according to a third embodiment of the present invention. Figure 5B shows a radiation pattern diagram of the broadband liquid crystal array antenna structure according to a third embodiment of the present invention. Referring to Figures 5A and 5B, the liquid crystal material used in the first liquid crystal layer 8 in this embodiment is MERCK GT7-29001.

[0075] As shown in Figures 5A and 5B, when no bias voltage is applied to the first liquid crystal layer 8, the center operating frequency of the broadband liquid crystal array antenna structure is 7.11 to 7.66 GHz with -10 dB as the reference point, the bandwidth is 0.55 GHz, and the bandwidth ratio is 7.30%. Also, when no bias voltage is applied to the first liquid crystal layer 8, the maximum gain at a reflection angle of 0 degrees is 7.02 dBi.

[0076] As shown in Figures 5A and 5B, when a bias is applied to the parasitic patch group 52, the center operating frequency of the broadband liquid crystal array antenna structure becomes 7.09 to 7.61 GHz with -10 dB as the reference point, the bandwidth becomes 0.52 GHz, and the bandwidth ratio becomes 6.90%. Furthermore, when a bias is applied to the parasitic patch group 52, the maximum gain at a reflection angle of 42 degrees is 6.23 dBi.

[0077] As shown in Figures 5A and 5B, when a bias is applied to the parasitic patch group 53, the center operating frequency of the broadband liquid crystal array antenna structure becomes 7.08 to 7.60 GHz with -10 dB as the reference point, the bandwidth becomes 0.52 GHz, and the bandwidth ratio becomes 6.90%. Furthermore, when a bias is applied to the parasitic patch group 53, the maximum gain at a reflection angle of -42 degrees is 6.25 dBi.

[0078] From Figures 3A to 5B above, it can be seen that the range in which the broadband liquid crystal array antenna structure performs beam scanning (also called the first angular range) is determined by the material of the first liquid crystal layer 8. When the material of the first liquid crystal layer 8 is JNC ZOC-A018XX or MERCK GT7-29001, when a bias is applied to the first liquid crystal layer 8, the broadband liquid crystal array antenna structure can perform beam scanning based on the first scanning angle (i.e., -42 degrees to 42 degrees). When the material of the first liquid crystal layer 8 is MERCK E7, when a bias is applied to the first liquid crystal layer 8, the first scanning angle becomes -52 degrees to 52 degrees.

[0079] To facilitate understanding, the characteristics of broadband liquid crystal array antenna structures using various liquid crystal materials are summarized in Table 2. Here, Table 2 uses -10 dB and a center operating frequency of 7.50 kHz as references. [Table 2]

[0080] In summary, the broadband liquid crystal array antenna structure provided by the embodiments of the present invention employs liquid crystal material to control its scanning beam. When a bias is applied to the liquid crystal material, the broadband liquid crystal array antenna structure can perform beam scanning based on a wide scanning range (-42° to 42° or -52° to 52°), and its continuous scanning range can cover 84° (or 104°), thereby meeting the requirements for high-precision ultra-wideband (UWB) indoor positioning.

[0081] Finally, it should be noted that the above embodiments are intended to illustrate the technical solutions of the present invention and are not intended to limit the invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art will understand that modifications can be made to the technical solutions described in the above embodiments, or that some or all of the technical features can be replaced with equivalents. Such modifications or replacements will not depart from the essence of the corresponding technical solutions within the scope of the various embodiments of the present invention. [Industrial applicability]

[0082] The present invention provides a broadband liquid crystal array antenna structure having a wide beam scanning range. [Explanation of symbols]

[0083] 1: First substrate layer 11: 1st top surface 12: 1st bottom surface 2: Second substrate layer 21: 2nd top surface 22: 2nd bottom surface 3: Third substrate layer 31:Third top surface 32: 3rd bottom surface 4: First surface unit 41: Large rectangular patch on the first surface 421, 422, 423, 424: Small rectangular patches on the first surface 5: Second surface unit 51: Rectangular patch on the second surface 52, 53: Parasitic patch group 521, 531: Large rectangular patch on the second surface 522, 532: Second surface small rectangular patch 523, 533: Second surface band-shaped patch 6: Third surface unit 61: Third surface rectangular patch 621, 622, 623: Third surface slots 7: Fourth surface unit 8: First liquid crystal layer

Claims

1. A first substrate layer having a first upper surface and a first lower surface, A second substrate layer having a second upper surface and a second lower surface, A third substrate layer having a third upper surface and a third lower surface, A first liquid crystal layer is laminated and connected between the second substrate layer and the third substrate layer, The first surface unit is arranged on the first upper surface, The second surface unit is positioned on the second upper surface, A third surface unit arranged on the third upper surface, The fourth surface unit is positioned on the third lower surface, Includes, When a bias is applied to the first liquid crystal layer, the broadband liquid crystal array antenna structure performs beam scanning based on a first angular range. Broadband liquid crystal array antenna structure.

2. The first surface unit includes a first surface large rectangular patch and four first surface small rectangular patches, The center point of the first surface large rectangular patch corresponds to the center point of the first liquid crystal layer, Two of the four small rectangular patches on the first surface are adjacent to the first side of the large rectangular patch on the first surface, and the other two of the four small rectangular patches on the first surface are adjacent to the second side of the large rectangular patch on the first surface. The first side faces the second side, The broadband liquid crystal array antenna structure according to claim 1.

3. The second surface unit includes a second surface rectangular patch and two groups of parasitic patches. The center point of the second surface rectangular patch corresponds to the center point of the first liquid crystal layer, One of the parasitic patch group is adjacent to the first side of the second surface rectangular patch, and another of the parasitic patch group is adjacent to the second side of the second surface rectangular patch. The first side faces the second side, The broadband liquid crystal array antenna structure according to claim 1.

4. The second surface rectangular patch is the main radiating patch. The broadband liquid crystal array antenna structure according to claim 3.

5. Each of the aforementioned parasitic patch groups includes a large rectangular patch on the second surface, a small rectangular patch on the second surface, and a band-shaped patch on the second surface. The large rectangular patch on the second surface and the small rectangular patch on the second surface are connected via the strip-shaped patch on the second surface. The second surface large rectangular patch is adjacent to the second surface rectangular patch, The second surface small rectangular patch is connected to the edge of the second upper surface. The broadband liquid crystal array antenna structure according to claim 3.

6. The third surface unit is a metal grounding layer. The broadband liquid crystal array antenna structure according to claim 1.

7. The third surface unit includes a third surface rectangular patch, The third surface rectangular patch includes three third surface slots arranged sequentially along a first direction, and further, the center point of the second of the three third surface slots corresponds to the center point of the first liquid crystal layer. The broadband liquid crystal array antenna structure according to claim 1.

8. The third surface slot is an H-shaped slot, The H-shape of the third surface slot extends along the second direction, The first direction is opposite to the second direction. The broadband liquid crystal array antenna structure according to claim 7.

9. The fourth surface unit is a fourth surface band-shaped patch, The fourth surface strip-shaped patch extends along the second direction, and further corresponds to the center point of the first liquid crystal layer, The broadband liquid crystal array antenna structure according to claim 1.

10. The fourth surface strip-shaped patch is a signal transmission line. The broadband liquid crystal array antenna structure according to claim 9.

11. The fourth surface strip-shaped patch is a microstrip line. The broadband liquid crystal array antenna structure according to claim 9.

12. The first surface unit, the second surface unit, the third surface unit, and the fourth surface unit are all made of a metallic material. The liquid crystal array antenna structure according to claim 1.

13. The first angular range is determined by the material of the first liquid crystal layer. The liquid crystal array antenna structure according to claim 1.

14. The aforementioned first angular range is from -42 degrees to 42 degrees. The liquid crystal array antenna structure according to claim 1.

15. The aforementioned first angular range is from -52 degrees to 52 degrees. The liquid crystal array antenna structure according to claim 1.

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