Miniaturized conformal antenna

Abstract

The present invention discloses a miniaturized conformal antenna, wherein the interior of the metal cavity is used to install an internal module, the flexible printed circuit board is conformally installed with the outer surface of the metal cavity, the microstrip patch antenna is fixedly connected with the flexible printed circuit board and is located on the side of the flexible printed circuit board away from the metal cavity, a plurality of microstrip patch antennas surround the flexible printed circuit board, one end of the feed network is electrically connected to each of the microstrip patch antennas, the other end of the feed network runs through the interior of the metal cavity and is electrically connected to the internal module, and the feed network and the radiation surface of the flexible printed circuit board are integrated and coplanar. The purpose of effectively utilizing the spatial structure of the sensor network node and utilizing the shielding effect of the metal cavity to reduce the influence of the internal module on the antenna radiation performance and the influence on the performance of the whole machine is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of antennas in wireless communications, and in particular to a miniaturized conformal antenna. Background Art

[0002] Miniaturized conformal antennas are used in broadcast spectrum monitoring sensor network nodes. In order to meet the requirements of broadcastability and concealment in battlefield environments, sensor network nodes must be miniaturized, and there are strict restrictions on their weight and center of gravity. The miniaturization of the antenna is the key to the miniaturization of the entire node.

[0003] According to antenna design theory, the antenna size is related to the wavelength corresponding to the working frequency band. Traditional omnidirectional antennas are usually three-dimensional symmetrical structures. In order to meet the requirements of being scatterable, it is necessary to add a radome outside the antenna structure to protect the antenna structure and achieve wave transmission. At the same time, in order to meet the omnidirectional radiation characteristics, there must be no metal material around the antenna radiator, otherwise it will cause distortion of the antenna radiation pattern and shift of the working frequency band. For this reason, the sensor network node needs to allocate a larger physical space to the antenna, resulting in the space of other modules such as channels, digital boards, and batteries being squeezed, and the performance of the whole machine is affected. Summary of the invention

[0004] The purpose of the present invention is to provide a miniaturized conformal antenna, aiming to solve the technical problems in the prior art that sensor network nodes cannot effectively utilize spatial structures, and internal modules are prone to affect the antenna radiation performance, thereby affecting the performance of the entire device.

[0005] To achieve the above-mentioned purpose, the present invention adopts a miniaturized conformal antenna, including a metal cavity, a flexible printed circuit board, a microstrip patch antenna and a feeding network, wherein the interior of the metal cavity is used to install an internal module, the flexible printed circuit board is conformally installed with the outer surface of the metal cavity, the microstrip patch antenna is fixedly connected to the flexible printed circuit board and is located on a side of the flexible printed circuit board away from the metal cavity, the number of the microstrip patch antennas is multiple, and the multiple microstrip patch antennas enclose the flexible printed circuit board, one end of the feeding network is electrically connected to each of the microstrip patch antennas, the other end of the feeding network passes through the interior of the metal cavity and is electrically connected to the internal module, and the feeding network and the radiation surface of the flexible printed circuit board are integrated in a coplanar design.

[0006] Among them, the metal cavity is arranged in a cylindrical structure, the flexible printed circuit board is conformally installed with the outer surface of the metal cavity, and a plurality of the microstrip patch antennas are circularly surrounded on the outer wall of the flexible printed circuit board to form omnidirectional radiation, and the number of the microstrip patch antennas surrounded on the outer wall of the flexible printed circuit board is an even number.

[0007] Wherein, the microstrip patch antenna includes a dielectric substrate, which is fixedly connected to the flexible printed circuit board and is located on a side of the flexible printed circuit board away from the outer wall of the metal cavity to form a conformal antenna array.

[0008] Among them, the microstrip patch antenna also includes a conductor patch and a ground plate, the conductor patch and the radiation surface of the flexible printed circuit board are integrated into a coplanar design and attached to the dielectric substrate, and the conductor patch is electrically connected to the feeding network, and the ground plate is fixedly connected to the dielectric substrate and is located at one end of the dielectric substrate away from the flexible printed circuit board.

[0009] Wherein, a plurality of short-circuit vias are arranged in the middle of the conductor patch, and the plurality of short-circuit vias are arranged in a horizontal row.

[0010] Among them, the outer wall of the metal cavity is provided with multiple accommodating grooves, and each accommodating groove is located directly below each corresponding conductor patch. The interior of each accommodating groove is filled with a dielectric gasket, and the outer wall of each dielectric gasket is flush with the outer wall of the metal cavity.

[0011] Wherein, each of the dielectric gaskets is arranged in an arc-shaped structure.

[0012] Wherein, the dielectric gasket is made of polytetrafluoroethylene material.

[0013] Wherein, the thickness of each dielectric gasket is 1 mm to 3 mm.

[0014] Wherein, the thickness of the flexible printed circuit board is 0.5mm-0.6mm.

[0015] A miniaturized conformal antenna of the present invention is used to install an internal module through the metal cavity, the flexible printed board is conformally installed with the outer surface of the metal cavity, the microstrip patch antenna is fixedly connected with the flexible printed board and is located on the side of the flexible printed board away from the metal cavity, the number of the microstrip patch antennas is multiple, and the multiple microstrip patch antennas enclose the flexible printed board, one end of the feed network is electrically connected to the microstrip patch antenna, and the other end of the feed network passes through the side wall of the metal cavity and is electrically connected to the internal module inside the metal cavity. The multiple microstrip patch antennas are enclosed by the flexible printed board on the outer wall of the metal cavity, and the internal space of the metal cavity is given to the internal module, so that the structural space is fully utilized, and the shielding effect of the metal cavity is utilized to reduce the influence of the internal module on the antenna radiation performance, and avoid the performance of the whole machine being affected. In this way, the sensor network node can effectively utilize the spatial structure, and the shielding effect of the metal cavity is utilized to reduce the influence of the internal module on the antenna radiation performance and the effect of the performance of the whole machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention 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 these drawings without paying creative work.

[0017] Figure 1 It is a schematic structural diagram of the miniaturized conformal antenna of the present invention.

[0018] Figure 2 It is a structural cross-sectional view of the miniaturized conformal antenna of the present invention.

[0019] Figure 3 It is a schematic structural diagram of the microstrip patch antenna of the present invention.

[0020] Figure 4 is a side view of the miniaturized conformal antenna of the present invention.

[0021] Figure 5 It is a standing wave curve diagram of the miniaturized conformal antenna of the present invention when no dielectric gasket is added.

[0022] Figure 6 It is a standing wave curve diagram of the miniaturized conformal antenna when a dielectric gasket is added to the present invention.

[0023] Figure 7 This is the E-plane radiation pattern of the miniaturized conformal antenna of the present invention.

[0024] Figure 8 This is the H-plane radiation pattern of the miniaturized conformal antenna of the present invention.

[0025] 100-miniaturized conformal antenna, 10-metal cavity, 11-receiving groove, 12-dielectric gasket, 20-flexible printed circuit board, 30-microstrip patch antenna, 31-dielectric substrate, 32-conductor patch, 33-short-circuit via, 34-ground plate, 40-feeding network, 41-microstrip line. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0027] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0028] See also Figures 1 to 8 The present invention provides a miniaturized conformal antenna 100, comprising a metal cavity 10, a flexible printed board 20, a microstrip patch antenna 30 and a feeding network 40, wherein the interior of the metal cavity 10 is used to install an internal module, the flexible printed board 20 is conformally installed with the outer surface of the metal cavity 10, the microstrip patch antenna 30 is fixedly connected to the flexible printed board 20, and is located on a side of the flexible printed board 20 away from the metal cavity 10, the number of the microstrip patch antennas 30 is multiple, and the multiple microstrip patch antennas 30 enclose the flexible printed board 20, one end of the feeding network 40 is electrically connected to each of the microstrip patch antennas 30, the other end of the feeding network 40 passes through the interior of the metal cavity 10, and is electrically connected to the internal module, and the feeding network 40 and the radiation surface of the flexible printed board 20 are integrated and coplanar.

[0029] In this embodiment, the cavity structure inside the metal cavity 10 is formed by mechanical processing, the flexible printed circuit board 20 is processed by conventional technology and has the characteristic of good consistency, the flexible printed circuit board 20 is conformally installed on the surface of the metal cavity 10 by adhesive or screw installation, the flexible printed circuit board 20 forms a natural radiation surface, and multiple microstrip patch antennas 30 are enclosed on the outer wall of the flexible printed circuit board 20, one end of the feed network 40 is electrically connected to each of the microstrip patch antennas 30, and the other end of the feed network 40 passes through the side wall of the metal cavity 10 and is electrically connected to the internal module inside the metal cavity 10. When multiple microstrip patch antennas 30 are arrayed, the feed network 40 can be integrated with the radiation surface of the flexible printed circuit board 20 by a microstrip line 41 or a coaxial transmission line, wherein the microstrip line 41 is preferably a transmission line. The feeding position in the feeding network 40 is welded to the microstrip line 41 through a flexible cable with a micro RF connector, and then penetrates through the opening on the outer wall of the metal cavity 10 to connect with the corresponding data transmission module inside, ensuring that the module can realize normal RF signal receiving and sending functions through the antenna.

[0030] The integrated coplanar design of the feed network 40 and the flexible printed circuit board 20 can reduce additional connecting devices, facilitate installation, and conform to the shape. The flexible printed circuit board 20 is conformally installed with the outer surface of the metal cavity 10, and the internal space of the metal cavity 10 is given to the internal module, so that the structural space is fully utilized, and the shielding effect of the metal is used to reduce the influence of the internal module on the radiation performance of the antenna, thereby avoiding the influence on the performance of the whole device.

[0031] Furthermore, the metal cavity 10 is arranged in a cylindrical structure, the flexible printed circuit board 20 is conformally installed with the outer surface of the metal cavity 10, and a plurality of the microstrip patch antennas 30 are circularly enclosed on the outer wall of the flexible printed circuit board 20 to form omnidirectional radiation, and the number of the microstrip patch antennas 30 enclosed on the outer wall of the flexible printed circuit board 20 is an even number.

[0032] In this embodiment, the metal cavity 10 is set in a cylindrical structure, and the multiple microstrip patch antennas 30 are surrounded in a circle on the outer wall of the flexible printed circuit board 20 to form omnidirectional radiation. By surrounding the multiple microstrip patch antennas 30 in a circle on the outer wall of the flexible printed circuit board 20, multiple independent directional beams are combined to form an omnidirectional beam, so that the device has omnidirectional coverage capability in all directions, meets the use requirements of omnidirectional antennas required by sensor network nodes, and also creates conditions for conformal design. In addition, the number of the microstrip patch antennas 30 surrounded on the outer wall of the flexible printed circuit board 20 is set to an even number, which can further improve the omnidirectional coverage capability of the device in all directions, and meets the use requirements of omnidirectional antennas required by sensor network nodes.

[0033] Furthermore, the microstrip patch antenna 30 includes a dielectric substrate 31, which is fixedly connected to the flexible printed circuit board 20 and is located on a side of the flexible printed circuit board 20 away from the outer wall of the metal cavity 10, and forms a conformal antenna array.

[0034] In this embodiment, the thickness of the dielectric substrate 31 is not greater than 0.5 mm, and the dielectric substrate 31 has good flexibility. After the flexible printed circuit board 20 is processed, the dielectric substrate 31 is bent and installed on the outer wall of the flexible printed circuit board 20 to form a conformal structure, that is, a conformal antenna array.

[0035] Furthermore, the microstrip patch antenna 30 further includes a conductor patch 32 and a ground plane 34, wherein the conductor patch 32 and the radiation surface of the flexible printed circuit board 20 are integrated and coplanar, and are attached to the dielectric substrate 31, and the conductor patch 32 is electrically connected to the feed network 40, and the ground plane 34 is fixedly connected to the dielectric substrate 31 and is located at one end of the dielectric substrate 31 away from the flexible printed circuit board 20. A plurality of short-circuit vias 33 are provided in the middle of the conductor patch 32, and the plurality of short-circuit vias 33 are arranged in a horizontal row.

[0036] In this embodiment, according to antenna design theory, the length of the conductor patch 32 is about 1 / 2 of the wavelength of the medium corresponding to the working frequency. The working frequency of the data transmission antenna is 1900MHz. If a dielectric substrate 31 with a dielectric constant of 2.55 is used, the corresponding length of the conductor patch 32 is about 54mm. In addition to the size increase caused by the feeding network 40, the antenna height size still exceeds the target requirement. Therefore, it is necessary to adopt miniaturization design means for the microstrip patch antenna 30. By setting a row of short-circuit vias 33 in the middle position of the conductor patch 32, the size of the conductor patch 32 can be reduced to half of the original size, that is, one quarter of the wavelength of the medium corresponding to the working frequency. At this time, the overall height size of the conductor patch 32 and the feeding network 40 can be controlled within 40mm, achieving a miniaturized design of the microstrip patch antenna 30.

[0037] Furthermore, the outer wall of the metal cavity 10 is provided with a plurality of receiving grooves 11, and each receiving groove 11 is located directly below each corresponding conductor patch 32, the interior of each receiving groove 11 is filled with a dielectric gasket 12, and the outer wall of each dielectric gasket 12 is flush with the outer wall of the metal cavity 10.

[0038] In this embodiment, the metal cavity 10 is machined to form the receiving groove 11, and the dielectric gasket 12 is embedded in the receiving groove 11. After the dielectric gasket 12 is embedded in the receiving groove 11, the outer surface of the dielectric gasket 12 is flush with the outer surface of the metal cavity 10, and then the flexible printed board 20 with the microstrip patch antenna 30 is installed on the outer surface of the receiving groove 11. At this time, each of the microstrip patch antennas 30 is composed of three parts: the conductor patch 32 attached to the outer surface of the flexible printed board 20, the dielectric gasket 12 embedded in the receiving groove 11, and the metal cavity 10 as the ground plane, which equivalently increases the dielectric thickness of the microstrip patch antenna 30, resulting in a wider working bandwidth. Since the conductor patch 32 adopts the miniaturization method of adding a row of the short-circuit vias 33 and a thinner thickness of the flexible printed circuit board 20 is selected, the standing wave bandwidth of the microstrip patch antenna 30 becomes narrower and cannot meet the working frequency band requirements of the digital antenna. Therefore, the working bandwidth of the microstrip patch antenna 30 is widened by adding the dielectric gasket 12 to the inner surface wall of the flexible printed circuit board, thereby solving the problem of narrowing the antenna bandwidth caused by miniaturization and conformal installation.

[0039] Furthermore, each of the dielectric gaskets 12 is arranged in an arc-shaped structure.

[0040] In this embodiment, the dielectric gasket 12 embedded in the receiving groove 11 is in an arc shape, which makes it easier and faster to embed the dielectric gasket 12 and facilitates the outer surface of the dielectric gasket 12 to be flush with the outer surface of the metal cavity 10.

[0041] Furthermore, the dielectric gasket 12 is made of polytetrafluoroethylene material. The thickness of each dielectric gasket 12 is 1 mm to 3 mm.

[0042] In this embodiment, the dielectric gasket 12 is preferably made of polytetrafluoroethylene, and the thickness of the dielectric gasket 12 is 2 mm. The dielectric gasket 12 can be directly processed and formed by mechanical processing.

[0043] Furthermore, the thickness of the flexible printed circuit board 20 is 0.5 mm to 0.6 mm.

[0044] In this embodiment, in order to enable the microstrip patch antenna 30 to be conformally attached to the surface of the cylindrical metal cavity 10, the thickness of the selected flexible printed circuit board 20 should not be too thick and the hardness should not be too high. Therefore, the board AD255A is selected with a thickness of 0.508 mm to meet the bending conformal installation requirements.

[0045] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A miniaturized conformal antenna, characterized in that: It includes a metal cavity, a flexible printed circuit board, a microstrip patch antenna and a feeding network, wherein the interior of the metal cavity is used to install an internal module, the flexible printed circuit board is conformally installed with the outer surface of the metal cavity, the microstrip patch antenna is fixedly connected to the flexible printed circuit board and is located on a side of the flexible printed circuit board away from the metal cavity, there are multiple microstrip patch antennas, and the multiple microstrip patch antennas enclose the flexible printed circuit board, one end of the feeding network is electrically connected to each of the microstrip patch antennas, the other end of the feeding network passes through the interior of the metal cavity and is electrically connected to the internal module, and the feeding network and the radiation surface of the flexible printed circuit board are integrated and coplanar; The metal cavity is arranged in a cylindrical structure, the flexible printed circuit board is conformally mounted with the outer surface of the metal cavity, a plurality of the microstrip patch antennas are circularly enclosed on the outer wall of the flexible printed circuit board to form omnidirectional radiation, and the number of the microstrip patch antennas enclosed on the outer wall of the flexible printed circuit board is an even number; The microstrip patch antenna comprises a dielectric substrate, a conductor patch and a ground plate, wherein the dielectric substrate is fixedly connected to the flexible printed circuit board and is located on a side of the flexible printed circuit board away from the outer wall of the metal cavity, and forms a conformal antenna array; the conductor patch and the radiation surface of the flexible printed circuit board are designed to be integrated and coplanar, and are attached to the dielectric substrate, and the conductor patch is electrically connected to the feed network, the ground plate is fixedly connected to the dielectric substrate and is located at one end of the dielectric substrate away from the flexible printed circuit board, a plurality of short-circuit vias are arranged in the middle of the conductor patch, and the plurality of short-circuit vias are arranged in a horizontal row; The outer wall of the metal cavity is provided with a plurality of receiving grooves, and each receiving groove is located directly below each corresponding conductor patch, the interior of each receiving groove is filled with a dielectric gasket, and the outer wall of each dielectric gasket is flush with the outer wall of the metal cavity.

2. The miniaturized conformal antenna according to claim 1, characterized in that: Each of the dielectric gaskets is arranged in an arc-shaped structure.

3. The miniaturized conformal antenna according to claim 2, characterized in that: The medium gasket is made of polytetrafluoroethylene material.

4. The miniaturized conformal antenna according to claim 3, characterized in that: The thickness of each dielectric gasket is 1 mm to 3 mm.

5. The miniaturized conformal antenna according to any one of claims 1 to 4, characterized in that: The thickness of the flexible printed circuit board is 0.5 mm to 0.6 mm.

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