Strip line feed structure, millimeter wave antenna, and human body security system

Abstract

The present application relates to a strip line feed structure, a millimeter wave antenna, and a human body security system. The strip line feed structure has a multilayer integrated circuit including a first metal layer provided with a first opening consistent with a bottom shape of a waveguide portion of an antenna and provided with a first metal patch in the first opening, a second metal layer as a ground layer, and a feed line layer provided between the first metal layer and the second metal layer and provided with a strip line provided with a metal profile structure at a terminal end of the strip line, the profile structure and the first metal patch being respectively axisymmetric with the extension direction of the strip line as a symmetric axis, being provided in a stacked manner in the up-down direction, and being provided with a dielectric substrate or a prepreg between each of the first metal layer, the feed line layer, and the second metal layer, and a through shielding ground via being formed around the opening and the strip line.

Description

TECHNICAL FIELD

[0001] The present application relates to antennas, and in particular to millimeter wave antenna elements. BACKGROUND

[0002] In the prior art, millimeter wave antennas involving microstrip line structures are used. The antennas of this structure need to form an air layer between the dielectric substrate and the ground layer, which increases the complexity of machining the metal base. In addition, because the air layer needs to be formed between the dielectric substrate and the ground layer, the prior art is only suitable for single-layer dielectric substrates and is not suitable for use in multi-layer integrated designs. For multi-layer integrated circuits, the air cavity at the bottom of the radiation layer means that not only does the bottom dielectric plate need to be slotted, but the cavity also needs to be maintained without deformation during the pressing process of the multi-layer plate, which is basically impossible. Furthermore, the air layer of the microstrip antenna dielectric substrate and the metal base needs to be assembled and used, relying on mechanical positioning holes for manual installation, and the assembly tolerance has a significant impact on the performance of the antenna. In addition, the air layer size of the microstrip line structure millimeter wave antenna is related to the working wavelength of the antenna, and when the system operating frequency increases and the wavelength becomes shorter, the size of the air layer also decreases, increasing the difficulty of machining the metal base. In addition, the millimeter wave antenna with microstrip line structure adopts a 50-ohm microstrip line edge feed method, which will lead to a close relationship between the directivity of the antenna and the operating frequency. For a wideband system, this will cause the directivity pattern to be inconsistent within the operating bandwidth of the antenna.

[0003] In addition, in the prior art, there is also a way of using a slot coupling method to achieve energy transfer between the antenna and the horn. In this method, the size of the slot is directly proportional to the working wavelength, and the performance of the antenna is very sensitive to the size of the slot, which requires very strict processing of the size of the slot and is difficult to process.

[0004] Furthermore, in the prior art, there is also a way of using a probe coupling method to achieve energy coupling. However, in the probe coupling method, the thickness of the dielectric substrate is very strict, and it is not possible to achieve a large bandwidth. SUMMARY

[0005] The present application provides a stripline feed structure and an antenna using the same, which at least solves at least one of the above problems.

[0006] One embodiment of the present application relates to a stripline feed structure for an antenna, having a multilayer integrated circuit as a stripline feed unit, the multilayer integrated circuit comprising: a first metal layer provided with a first opening in conformity with a bottom shape of a waveguide portion of the antenna, and provided with a first metal patch within the first opening; a second metal layer as a ground layer; and a feed line layer provided between the first metal layer and the second metal layer, provided with a stripline, and provided with a metal profile structure at a terminal end of the stripline, the profile structure being axially symmetrical with the first metal patch with a direction of extension of the stripline as an axis of symmetry, and being stacked in a vertical direction, and a dielectric substrate or a prepreg being provided between each of the first metal layer, the feed line layer, and the second metal layer, and a through shield ground via being formed around the opening and the stripline.

[0007] According to the above-described stripline feed structure, the opening is a rectangular opening, and the first metal patch is in a rectangular shape.

[0008] According to the above-described stripline feed structure, the profile structure is in an E-shape.

[0009] According to the above-described stripline feed structure, a diagonal intersection of a rectangle formed by the E-shaped structure coincides with a diagonal intersection of the first metal patch in a direction perpendicular to the stacking direction.

[0010] According to the above-described stripline feed structure, the profile structure is in a G-shape or a W-shape.

[0011] According to the above-described stripline feed structure, the third metal layer is further provided between the first metal layer and the feed line layer, and is adjacent to the first metal layer and the feed line layer with a dielectric substrate or a prepreg therebetween, the third metal layer is provided with a second opening corresponding to the first opening, and is provided with a second metal patch corresponding to the first metal patch.

[0012] The present application relates to a millimeter wave antenna comprising the above-described stripline feed structure; and a waveguide horn array having a plurality of waveguide horn components each comprising a waveguide portion and a horn portion, the waveguide portion being provided at a position of the opening.

[0013] The present application also relates to a human body security system comprising the above-described millimeter wave antenna. The stripline feed structure according to the present application and the antenna using the same have at least one of the following advantages: a wide operating bandwidth, stable radiation directivity, easy to be manufactured by using an integrated circuit process, easy to be integrated with a system, and the like. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1is a top view of a waveguide horn array to which an embodiment of the present application relates;

[0015] Figure 2 is a side view of a waveguide horn array to which an embodiment of the present application relates;

[0016] Figure 3 is a schematic diagram of a stripline feed structure to which an embodiment of the present application relates;

[0017] Figure 4 is a schematic diagram of the top layer of a stripline feed structure to which an embodiment of the present application relates;

[0018] Figure 5 is a schematic diagram of the feed line layer of a stripline feed structure to which an embodiment of the present application relates;

[0019] Figure 6 is a schematic diagram of the bottom layer of a stripline feed structure to which an embodiment of the present application relates;

[0020] Figure 7 is a top view of a stripline feed structure provided with a shield ground via to which an embodiment of the present application relates;

[0021] Figure 8 is another example of a schematic diagram of a stripline feed structure to which an embodiment of the present application relates. DETAILED DESCRIPTION

[0022] The features and exemplary embodiments of the various aspects of the present application will be described in detail below with reference to the drawings. The following detailed description is merely intended to explain the present application and is not intended to limit the present application. The present application can be implemented without some of the specific details. The following description of the embodiments is merely intended to provide a better understanding of the present application by showing examples of the present application.

[0023] Embodiments of the present application relate to an array antenna that can be suitable for integration into a circuit. The antenna comprises a waveguide horn array and a stripline feed structure composed of a plurality of layers of an integrated circuit.

[0024] Figure 1 is a top view of a waveguide horn array to which an embodiment of the present application relates; Figure 2 is a side view of a waveguide horn array to which an embodiment of the present application relates. The waveguide horn array to which an embodiment of the present application relates is partially manufactured by machining a metal and has a plurality of waveguide horn portions. The waveguide horn portion includes a waveguide portion 1 and a horn portion 2. As shown in FIG. 2, the waveguide horn portion includes a waveguide portion 1 and a horn portion 2. The waveguide portion 1 is a portion of the waveguide horn portion that is formed by machining a metal and has a waveguide shape. The horn portion 2 is a portion of the waveguide horn portion that is formed by machining a metal and has a horn shape. The waveguide portion 1 and the horn portion 2 are connected to each other. Figure 1 and 2As shown, the waveguide horn portion is formed by metal processing. The waveguide portion 1 is in a cubic shape, having a rectangular bottom surface. The horn portion 2 is in a horn shape with the upper part wider and the lower part narrower. The pin column (not shown in the figure) on the waveguide horn array and the pin hole (not shown in the figure) made on the stripline feeding structure are aligned and combined together to form the antenna.

[0025] Optionally, the waveguide horn array shown here is a structure in which the rectangular waveguide gradually changes into the rectangular horn, but this transition form is not unique and can be modified into a combination of a rectangular waveguide gradually changing into a conical horn, a circular waveguide gradually changing into a rectangular horn, a circular waveguide gradually changing into a conical horn, etc.

[0026] Figure 3 An example structure of a multilayer integrated circuit is shown. The multilayer integrated circuit constitutes a stripline feeding structure. As shown, the multilayer integrated circuit 20 includes a first layer circuit 21, a feeding layer 23, and a second layer circuit 25, and a dielectric substrate 22 and a dielectric substrate 24 are respectively provided between the layers. The dielectric substrates here can also be provided as prepregs.

[0027] Figure 4 is Figure 3 An opening diagram of the top layer of the stripline feeding structure is shown. In Figure 4 , an opening diagram of the first layer circuit 21 of Figure 3 is shown. As the top layer of the stripline feeding structure, a rectangular opening 211 is made. Inside the rectangular opening 211, a rectangular metal patch 212 is provided as a radiating patch. The size of the rectangular opening 211 is consistent with the size of the rectangular waveguide of the waveguide horn array. The waveguide portion 1 in the waveguide horn array is provided at the position of the rectangular opening 211

[0028] Optionally, in the above embodiment, a rectangular opening is made in the top layer of the stripline feeding structure, and a rectangular patch is made in the opening. However, the opening shape and patch shape here are not unique, and the opening shape can be changed to a circular shape, a trapezoidal shape, or a spindle type, corresponding to the shape of the waveguide.

[0029] Optionally, in the above embodiment, only one radiating patch is made in the opening of the top layer of the stripline feeding structure. However, the number and position of the radiating patch are not unique, and multiple radiating patches can be made in the opening of the top layer, and radiating patches can also be arranged at corresponding positions of other layers.

[0030] Figure 5 is Figure 3A planar view of the feeding layer of the strip-line feeding structure is shown. The feeding layer 23 of the strip-line has a strip-line 231, the end of which is designed as an E-shaped structure 232 made of metal at the position corresponding to the rectangular opening. The E-shaped structure 232 is axisymmetric with the patch 212 with the extension direction of the strip-line 231 as the axis of symmetry. In addition, the E-shaped structure 232 and the patch 212 are arranged in a stacked manner in the vertical direction, and the center of the diagonal of the rectangle formed by the E-shaped structure 232 and the center of the diagonal of the patch 212 coincide in the direction perpendicular to the stacking direction. Here, the length and width of the E-shaped structure 232 and the patch 212 are not limited to complete coincidence, but can be set as needed. By designing the E-shaped structure 232 to cooperate with the patch 212, the resonant frequency and operating bandwidth of the antenna are determined. Through this simple structure, the bandwidth can be expanded, and it is relatively easy to achieve in production.

[0031] In addition, as shown in Figure 5 Shielding ground vias 230 are made on both sides. The shielding ground vias 230 are arranged along the edges of the rectangular opening 211 and along both sides of the strip-line 231. The shielding ground vias 230 can limit the lateral spread of electromagnetic waves, achieving efficient resonant coupling and electromagnetic wave radiation.

[0032] Optionally, as shown in Figure 5 The strip-line feeding layer is designed as an E-shaped structure at the position corresponding to the rectangular opening, and the middle horizontal line of the E is electrically connected to the strip-line. However, this structure is not unique, and can be changed to any special-shaped structure intended to expand the bandwidth. For example, the special-shaped structure can be designed as a G-shaped structure, with the vertical pen of the G-shaped structure electrically connected to the strip-line; or a Wang-shaped structure, with the vertical pen or the middle horizontal pen of the Wang-shaped structure electrically connected to the strip-line.

[0033] Optionally, as shown in Figure 5 The strip-line feeding layer is in a single-ended form, but can be designed as a corresponding differential form as needed.

[0034] Figure 6 A planar view of the bottom layer of the strip-line feeding structure is shown. Figure 3 The second layer circuit 25 in Figure 3 is the bottom layer, which is a complete ground layer.

[0035] Optionally, in the above embodiment, the bottom layer of the strip-line feeding structure is a complete ground layer, but is not limited thereto, and the bottom layer can be designed as a corresponding defective structure as needed.

[0036] In addition, in the above embodiment, the top layer of the stripline feed structure is the first layer, the feed line layer is the second layer, and the bottom layer is the third layer. However, this layering is not unique, as long as the feed line layer is located between the upper ground layer and the lower ground layer, the stripline feed structure can be formed.

[0037] Figure 7 is a top view of a stripline feed structure provided with a shielding ground via according to an embodiment of the present application. That is, in the feed line layer 23 of the stripline, the shielding ground via 230 is formed from top to bottom through each layer.

[0038] Figure 8 is another example of a stripline feed structure according to an embodiment of the present application. In the top layer, i.e., the first layer circuit 31 of the stripline feed structure, a rectangular opening is formed, and a rectangular patch is formed in the opening. The size of the rectangular opening is consistent with the size of the rectangular waveguide of the waveguide horn array. The second layer circuit 33 can be provided as a space layer, or a rectangular metal patch can be provided at a position corresponding to the metal patch 212 of the second layer circuit 22. The upper and lower metal patches are respectively axisymmetric structures, and the intersection points of the diagonals of the upper and lower rectangular metal patches also coincide in the direction perpendicular to the stacking direction. The dielectric substrate 32 is provided between the first layer circuit 31 and the second layer circuit 33. The third layer circuit 35 is the feed line layer of the stripline feed structure, and a stripline is provided. The end of the stripline is designed as a metal E-shaped structure at the position corresponding to the rectangular opening, for expanding the antenna bandwidth. The semi-cured sheet 34 is provided between the second layer circuit 33 and the third layer circuit 35. The bottom layer, i.e., the fourth layer circuit 37 of the stripline feed structure is a ground layer. The shielding ground via is formed around the rectangular opening of the stripline feed structure, and the shielding ground via is also provided on both sides of the extension portion and penetrates the stripline feed structure. In this embodiment, two metal patches are provided, thereby increasing the resonance points. However, multiple metal patches can also be provided to achieve multiple resonance points.

[0039] As described above, the stripline feed structure part of the antenna is only composed of a dielectric substrate, a semi-cured sheet, and a circuit pattern, and has a simple structure, is suitable for being manufactured by an integrated circuit process, and simplifies the assembly process. In addition, the stripline feed structure of the antenna can be integrated with the radio frequency module of the system on the same circuit, without being manufactured as a separate module, thereby improving the integration degree of the system. The performance of the stripline feed structure of the antenna is determined by the pattern processing precision of the metal layer, and the precision of the integrated circuit process is sufficient to ensure the yield and reliability of the performance of the antenna.

[0040] In addition, according to the present application, the operating frequency and bandwidth of the antenna have small correlation with the thickness of each layer of the dielectric substrate, and are not sensitive to the thickness of the dielectric substrate, and the selection of the dielectric substrate is more flexible.

[0041] In addition, according to the application, the number of layers of the strip line feeding structure of the antenna is small, and only three layers are needed to realize it. The energy of the strip line feeding structure of the antenna is fed to the patch from the bottom of the "E" type structure of the feeding layer, avoiding the problem of inconsistent directionality of broadband signal radiation caused by the edge feeding mode.

[0042] In addition, according to the application, the relative bandwidth of the antenna VSWR (voltage standing wave ratio) is less than 2, reaching 25%.

[0043] The millimeter wave antenna according to the application can be used in human body security equipment.

[0044] Although the embodiments and specific examples of the application are described above in combination with the drawings, those skilled in the art can make various modifications and changes without departing from the concept and scope of the application, and such modifications and changes fall within the scope defined by the claims.

Claims

1. A millimeter wave antenna, wherein, Comprising: a stripline feed structure; and a waveguide horn array having a plurality of waveguide horn components including a waveguide portion and a horn portion, the waveguide horn array is located on one side of the stripline feed structure, the stripline feed structure has a multilayer integrated circuit, the multilayer integrated circuit includes: a first metal layer provided with a first opening in conformity with a bottom shape of the waveguide portion of the antenna, and a first metal patch provided in the first opening; a second metal layer as a ground layer; and a feed line layer provided between the first metal layer and the second metal layer, directly provided with a stripline, provided with a metal profile structure at a terminal end of the stripline, the profile structure is respectively axisymmetric with the first metal patch with the extension direction of the stripline as the axis of symmetry, and is stacked in the up-down direction, a dielectric substrate or a prepreg is provided between each layer of the first metal layer, the feed line layer and the second metal layer, a through shielding ground via is formed around the opening and the stripline, the opening is a rectangular opening, and the first metal patch is a rectangular shape, the profile structure is an E-shaped structure, the diagonal intersection of the rectangle formed by the E-shaped structure coincides with the diagonal intersection of the first metal patch in the direction perpendicular to the stacking direction, the length and width of the E-shaped structure do not coincide with the first metal patch, and the waveguide portion is provided at the position of the opening, the multilayer integrated circuit further includes a third metal layer provided between the first metal layer and the feed line layer, and separated from the first metal layer and the feed line layer by a dielectric substrate or a prepreg, a rectangular metal patch is provided at a position corresponding to the first metal patch on the third metal layer, and the second metal layer is a complete ground layer.

2. A human body security system, wherein, a millimeter wave antenna according to claim 1 is included.

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