UWB antenna array

Abstract

The invention provides a UWB antenna array. The antenna array comprises two antennas which are symmetrically arranged, and the two antennas are arranged according to a half-wavelength interval of a target frequency; the antenna is formed by folding a yagi antenna and forms a microstrip balun structure; the antenna is folded to form two resonance arms; a gap exists between the two resonance arms; the two excitation elements are respectively and vertically arranged relative to the gaps of the two antennas; a ground plane defect graph structure is also arranged between the antennas; and the ground plane defect pattern structure is symmetrically arranged relative to a center line between the two antennas. The antenna array provided by the invention can meet the requirements of miniaturization, unidirectivity, isolation and wide bandwidth at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of antenna design, and in particular to a UWB antenna array. Background Art

[0002] With the vigorous development of wireless communication technology, Ultra-Wide Band (UWB) wireless communication technology has gained wide attention for its advantages such as wide frequency band and low power consumption. In some cases, there is a need to measure the single-plane incident angle of the UWB system. In response to this demand, the UWB system calculates the incident angle by measuring the phase difference of the signal reaching each antenna in the array and the known relative position of the antenna. However, since the UWB system is usually used in handheld devices, the back-reflected signal (reflected by the human body) brought by the omnidirectional antenna will become an interference signal for measuring the phase. At the same time, due to the high operating frequency of the UWB system, the half-wavelength required for the antenna spacing is relatively small. In addition, the isolation and bandwidth design between arrays also need to meet certain conditions. Therefore, it is necessary to design an antenna that meets the requirements of miniaturization, unidirectionality, isolation and bandwidth design at the same time. Summary of the invention

[0003] In order to at least partially solve the problems existing in the prior art, the present invention provides a UWB antenna array.

[0004] A UWB antenna array comprises: two symmetrically arranged antennas, and the two antennas are placed at a half-wavelength interval of a target frequency; the antennas are formed by folding a Yagi antenna to form a microstrip balun structure; the antennas are folded to form two resonant arms; there is a gap between the two resonant arms; two excitation elements are respectively arranged perpendicularly relative to the gap of the two antennas; a ground plane defect pattern structure is also arranged between the antennas; the ground plane defect pattern structure is symmetrically arranged relative to the midline between the two antennas.

[0005] Exemplarily, the ground plane defect pattern structure is a triangular ground plane protrusion pattern structure; the triangular ground plane protrusion pattern structure is used to achieve decoupling of a common signal induction current path between the two antennas.

[0006] Exemplarily, the target frequency is 8 GHz.

[0007] Exemplarily, the length of the antenna array is 32 mm, wherein the length is the distance between one end of one antenna and the other end of another antenna.

[0008] Exemplarily, the folded antenna comprises two first transverse portions, two longitudinal resonant arms, two opposite second transverse portions and longitudinal portions respectively arranged on the outside of the transverse portions; wherein the first transverse portions, the longitudinal resonant arms, the second transverse portions and the longitudinal portions are internally connected.

[0009] Exemplarily, the slot is formed between the two longitudinal resonant arms; the two antennas are coupled to the relative excitation elements through the corresponding slots to achieve a larger working bandwidth.

[0010] Exemplarily, a feeding point is provided on a side of the two first transverse portions away from the second transverse portion, and the feeding point is provided on an extension line of the gap.

[0011] Exemplarily, the antenna connects the feeding point to a 50 ohm microstrip feed line through the microstrip balun.

[0012] Exemplarily, the first transverse portion and the second transverse portion are parallel to form a total transverse portion; the two excitation elements are respectively parallel to the total transverse portion, and the distance between the two excitation elements and the transverse side edges of the total transverse portion is 3.3 mm.

[0013] Exemplarily, the first transverse portion and the second transverse portion have the same transverse length, which is 6.2 mm.

[0014] The UWB antenna array provided by the present invention comprises two symmetrically arranged antennas, and the two antennas are placed at a half-wavelength interval of the target frequency to ensure a wider bandwidth of the antenna array; the antenna is formed by folding a Yagi antenna and forming a microstrip balun structure, which can not only meet the requirement of unidirectionality, but also realize miniaturization of the antenna after folding; the antenna forms two resonant arms by folding; there is a gap between the two resonant arms, and two excitation elements are respectively arranged vertically relative to the gap of the two antennas to realize the excitation of the antenna signal; a ground plane defect pattern structure is also arranged between the antennas; the ground plane defect pattern structure is symmetrically arranged relative to the midline between the two antennas, and the setting of the ground plane defect pattern structure can isolate the two antennas. Therefore, the antenna array provided by the present scheme can simultaneously meet the requirements of miniaturization, unidirectionality, isolation and wide bandwidth.

[0015] A series of simplified concepts are introduced in the summary of the invention, which will be further described in detail in the detailed description. The summary of the invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0016] The advantages and features of the present invention are described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following drawings of the present invention are used as part of the present invention for understanding the present invention. The drawings show the embodiments of the present invention and their descriptions, and are used to explain the principles of the present invention. In the drawings,

[0018] Figure 1 is a schematic structural diagram of an antenna array according to an exemplary embodiment of the present invention;

[0019] Figure 2 FIG. 4 is a schematic structural diagram of an antenna array according to another exemplary embodiment of the present invention.

[0020] The above drawings include the following reference numerals:

[0021] 10. Antenna; 11. Resonant arm; 12. Slot; 13. Feeding point; 20. Excitation element; 30. Ground plane defect graphic structure. DETAILED DESCRIPTION

[0022] In the following description, a large amount of details are provided so that the present invention can be thoroughly understood. However, it will be appreciated by those skilled in the art that the following description only exemplarily illustrates a preferred embodiment of the present invention, and the present invention can be implemented without one or more such details. In addition, in order to avoid confusion with the present invention, some technical features well known in the art are not described in detail.

[0023] See also Figure 1 , providing a UWB antenna array. The antenna array provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0024] A UWB antenna array includes: two symmetrically arranged antennas 10, and the two antennas 10 are placed at a half-wavelength interval of a target frequency; the antenna 10 is formed by folding a Yagi antenna 10 to form a microstrip balun structure; the antenna 10 forms two resonant arms 11 by folding; there is a gap 12 between the two resonant arms 11; two excitation elements 20 are respectively arranged perpendicular to the gaps 12 of the two antennas 10; a ground plane defect pattern structure 30 is arranged between the antennas 10; the ground plane defect pattern structure 30 is symmetrically arranged relative to the midline between the two antennas 10.

[0025] The UWB system operates at a high frequency, so the half wavelength required for antenna spacing is relatively small, so the spacing between antennas needs to be reduced. Further, the antenna array includes two antennas 10, and the spacing between antennas 10 is small, which can meet the high operating frequency requirements of the UWB system.

[0026] For example, the target frequency is 8 GHz. The two antennas may be placed at a half-wavelength spacing of 8 GHz. Furthermore, the length of the antenna array is 32 mm, where the length is the distance between one end of one antenna 10 and the other end of another antenna 10. The antenna array of this size has the characteristic of a small size, thereby realizing the miniaturization of the antenna array.

[0027] Exemplarily, the antenna 10 is a MIMO (Multiple-in Multiple-out) type antenna. MIMO is a radio antenna technology that uses multiple antennas at the transmitter and receiver to provide multiple signal paths to carry data. MIMO can achieve beamforming, transmit diversity and receive diversity.

[0028] Furthermore, antenna 10 is a Yagi antenna. The Yagi antenna is an end-fire antenna composed of an active array (generally a folded array), a passive reflector and a number of passive directors arranged in parallel. The Yagi antenna is designed to be folded to reduce its size, and this design also introduces a planar balun. Among them, the balun structure is also called a balanced-unbalanced transformer (Balance-Unbalance Transformer, referred to as Balun). Exemplarily, the antenna 10 connects the feeding point to a 50 ohm microstrip feeder through a microstrip balun. That is, the Yagi antenna is folded in this solution, and a planar balun is introduced to achieve the characteristic of directly connecting the antenna feed port to a 50 ohm impedance line. This design makes it easy to connect the antenna to the system RF routing.

[0029] Exemplarily, the antenna array may also include a ground. Antenna 10 may be superimposed on the ground. Furthermore, the structure of the ground may be changed to form a DGS (Defected Ground Structure). The design of the defective ground structure can make the isolation between antennas higher, so as to reduce the phase interference of the system measurement and increase the angle measurement accuracy. At the same time, because the reference ground plane under the antenna body is relatively complete, the antenna body is not affected by other metal objects under the antenna, and the characteristic of being able to be deployed close to other objects is achieved.

[0030] Exemplarily, the DGS is a ground plane defect pattern structure disposed between the antennas and is symmetrically disposed relative to a midline between the antennas, and can effectively balance the two antennas while isolating the two antennas, thereby ensuring the directivity of the antenna array.

[0031] Exemplarily, the ground plane defect pattern structure 30 may be a T-shaped, triangular or other structure. Further, the ground plane defect pattern structure is a triangular ground plane protrusion pattern structure; the triangular ground plane protrusion pattern structure is used to achieve decoupling of the common signal induction current path between the two antennas, thereby improving the isolation between the two antennas. Further, the ground plane defect pattern structure 30 may be set at the center position between the two antennas.

[0032] The UWB antenna array provided by the present invention comprises two antennas arranged symmetrically, and the two antennas are placed at a half-wavelength interval of the target frequency to ensure a wider bandwidth of the antenna array; the antenna is folded from a Yagi antenna and forms a microstrip balun structure, which can not only meet the requirements of unidirectionality, but also the folded antenna can make the antenna body on the same metal layer of the PCB (printed circuit board), which brings the advantage that the antenna body is easily placed in the inner layer of the PCB to reduce its size relative to the wavelength, so as to achieve the purpose of miniaturization of the antenna; the antenna forms two resonant arms by folding; there is a gap between the two resonant arms, and two excitation elements are respectively arranged vertically relative to the gaps of the two antennas to realize the excitation of the antenna signal; a ground plane defect pattern structure is also arranged between the antennas; the ground plane defect pattern structure is symmetrically arranged relative to the midline between the two antennas, and the setting of the ground plane defect pattern structure can isolate the two antennas, so the antenna array provided by the present scheme meets the requirements of miniaturization, unidirectionality, isolation and wide bandwidth at the same time. Moreover, the antenna array can be applied to the single-plane incident angle measurement requirements of the UWB system in small devices, and can resist the signal interference generated by the back multipath effect. At the same time, since the antenna body only occupies one layer of the PCB, its integration in the system PCB does not affect the stacking selection of the system PCB.

[0033] Exemplarily, the antenna array as a whole may be a symmetrical structure, that is, the antenna, the excitation element and the ground plane defect pattern structure are all symmetrical about a certain straight line.

[0034] For example, Figure 1 As shown, the folded antenna 10 includes two first transverse portions, two longitudinal resonant arms 11, two opposite second transverse portions and longitudinal portions respectively arranged on the outside of the transverse portions; wherein the first transverse portions, the longitudinal resonant arms 11, the second transverse portions and the longitudinal portions are internally connected.

[0035] Exemplarily, a slot 12 is formed between the two longitudinal resonant arms 11; the two antennas 10 are coupled to the relative excitation elements 20 via the corresponding slots 12 to achieve a larger working bandwidth.

[0036] Exemplarily, the two first transverse portions are provided with a feeding point on a side away from the second transverse portion, and the feeding point 13 is provided on an extension line of the slot 12. The feeding point may be formed by providing a notch in the first transverse portion. This arrangement of the feeding point allows the signal to be transmitted better, so as to connect the feeding point to a 50 ohm microstrip line feeder.

[0037] Exemplarily, the first transverse portion and the second transverse portion are parallel to form a total transverse portion; the two excitation elements 20 are respectively parallel to the total transverse portion, and the distance between the two excitation elements 20 and the transverse side edges of the total transverse portion is 3.3 mm.

[0038] Exemplarily, the first transverse portion and the second transverse portion have the same transverse length, which is 6.2 mm.

[0039] Exemplarily, the substrate of the antenna array is FR4, which has a relative dielectric constant of 4.4, a dielectric loss angle of 0.02, and a total thickness of 1.0 mm.

[0040] Exemplarily, after the antenna array design parameters are optimized, the generated antenna array design is printed on a circuit board for manufacturing. The manufactured antenna array can be used for single-plane incident angle measurement of UWB systems in small devices.

[0041] For example, Figure 2 The following are examples of the dimensions of the antenna array. The dimensions are in mm. The x direction is the horizontal direction and the y direction is the vertical direction.

[0042] Further, Figure 2 The simulation of the antenna array shows that in the frequency range of 6.6 to 8.7 GHz, the simulated |S 11 | is less than -10dB, and the relative bandwidth formed is about 28%. Therefore, the operating frequency range of the antenna array provided by this scheme is 6.6 to 8.7GHz, which meets the available working bandwidth required by the UWB protocol. And the simulated gain achieved in the required working frequency band is about 3.7dBi. The forward and backward gain ratio of a single antenna reaches 24dB at 8GHz. The isolation between the dual antennas is greater than 15dB in the entire working band. In addition, the radiation pattern of the antenna array shows that its antenna forward gain is relatively average and has good directivity. Therefore, according to the miniaturized Yagi antenna dual antenna array with microstrip line balun in the present invention, it is possible to achieve high isolation, a bandwidth that meets the UWB standard, a stable forward radiation pattern and a high forward and backward gain ratio, which is suitable for the application of anti-multipath effect plane angle of incidence measurement in UWB systems. In addition, due to its overall size and processing materials, it has a wide range of applicable characteristics such as low cost, small size and anti-interference, and is particularly suitable for the application of UWB systems in high incident angle measurement accuracy equipment. At the same time, both simulation and measurement show that the antenna array provided by the present invention is easy to integrate into a circuit board, and various indicators of the antenna array are significantly better than those of an ordinary microstrip line antenna array.

[0043] In the description of the present invention, it is necessary to understand that the orientation or positional relationship indicated by directional words such as "front", "back", "up", "down", "left", "right", "lateral", "longitudinal", "vertical", "horizontal", "top", "bottom", etc. is usually based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present invention; the directional words "inside" and "outside" refer to the inside and outside relative to the contour of each component itself.

[0044] For ease of description, regional relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the regional positional relationship between one or more components or features shown in the figure and other components or features. It should be understood that regional relative terms include not only the orientation of the components as described in the figure, but also different orientations in use or operation. For example, if the components in the accompanying drawings are inverted as a whole, the components "above other components or features" or "above other components or features" will include the situation where the components are "below other components or structures" or "below other components or structures". Therefore, the exemplary term "above" may include both "above" and "below". In addition, these components or features may also be positioned at other different angles (e.g., rotated 90 degrees or other angles), and this article is intended to include all of these situations.

[0045] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, parts, components and / or combinations thereof.

[0046] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0047] The present invention has been described by the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the present invention is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope of the protection claimed by the present invention. The protection scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A UWB antenna array, characterized in that: include: Two symmetrically arranged antennas, with the two antennas placed at a half-wavelength interval of the target frequency; The antenna is formed by folding a Yagi antenna and forming a microstrip balun structure; The antenna is folded to form two resonant arms; there is a gap between the two resonant arms; Two excitation elements are respectively arranged vertically relative to the slots of the two antennas; A ground plane defect pattern structure is also arranged between the antennas; the ground plane defect pattern structure is arranged symmetrically with respect to the midline between the two antennas.

2. According to the UWB antenna array of claim 1, the ground plane defect pattern structure is a triangular ground plane protrusion pattern structure; the triangular ground plane protrusion pattern structure is used to achieve decoupling of the shared signal induction current path between the two antennas.

3. The UWB antenna array according to claim 1, characterized in that: The target frequency is 8 GHz.

4. The UWB antenna array according to claim 3, characterized in that: The length of the antenna array is 32 mm, wherein the length is the distance between one end of one antenna and the other end of another antenna.

5. The UWB antenna array according to any one of claims 1 to 4, characterized in that: The folded antenna comprises two first transverse portions, two longitudinal resonant arms, two opposite second transverse portions and longitudinal portions respectively arranged on the outside of the transverse portions; wherein the first transverse portions, the longitudinal resonant arms, the second transverse portions and the longitudinal portions are connected to each other.

6. The UWB antenna array according to claim 5, characterized in that: The slot is formed between the two longitudinal resonant arms; the two antennas are coupled to the relative excitation elements through the corresponding slots to achieve a larger working bandwidth.

7. The UWB antenna array according to claim 6, characterized in that: The two first transverse portions are provided with a feeding point on a side away from the second transverse portion, and the feeding point is arranged on an extension line of the gap.

8. The UWB antenna array according to claim 7, characterized in that: The antenna connects the feeding point to a 50 ohm microstrip feed line through the microstrip balun.

9. The UWB antenna array according to claim 5, characterized in that: The first transverse portion and the second transverse portion are parallel to form a total transverse portion; the two excitation elements are respectively parallel to the total transverse portion, and the distance between the two excitation elements and the transverse side edges of the total transverse portion is 3.3 mm.

10. The UWB antenna array according to claim 5, characterized in that: The first transverse portion and the second transverse portion have the same transverse length, which is 6.2 mm.

Images