Design method of UWB (Ultra Wideband) three-antenna device suitable for miniaturized terminal

Abstract

The invention provides a design method of a UWB three-antenna device suitable for a miniaturized terminal, and belongs to the technical design field of UWB antennas. The method comprises the following steps: for a UWB three-antenna device comprising three UWB antenna units, respectively forming a gap corresponding to a quarter wavelength on floors on two sides of a middle UWB antenna unit; when the antenna feeds, floor current flows from one side to the other side along the edge path of the gap and is reversed after passing through the path with the half wavelength, so that the floor current on the two sides of the antenna flows leftwards in the same direction at the same time. In order to reduce the influence of slotting, the method can also be used for respectively slotting a slot smaller than 1 / 8 wavelength on floors on two sides of a middle UWB antenna unit of the UWB three-antenna device, and then bridging a capacitor on each slot. The problem that directional diagram pits are formed in the front area of the antenna due to the fact that currents on the two sides of a traditional scheme are reverse can be solved, and the consistency of directional diagrams of the three unit antennas is effectively guaranteed.

Description

Technical Field

[0001] The invention belongs to the field of ultra-wideband antenna technology design, and in particular relates to a UWB three-antenna device design method suitable for a miniaturized terminal. Background Art

[0002] Ultra Wideband (UWB) is a carrier-free narrow pulse communication technology with ns-ps level transmission and reception. Since the time width of UWB pulse is extremely short, it can be used for distance measurement with high-precision timing and angle positioning. Compared with other indoor positioning technologies, this technology has many advantages such as high positioning accuracy, strong anti-multipath capability, and good confidentiality. It is widely used in IOT products such as smart phones, smart cars and smart homes.

[0003] To achieve accurate angle measurement in three-dimensional space, the three UWB antenna units need to have good consistency, especially the directional pattern within the tested FOV (Field of View) needs to be highly consistent to ensure the accuracy and stability of angle measurement; however, due to the requirements of miniaturization and thinness of terminal product ID, the three units of UWB antenna are very compact, and there will be serious mutual coupling and directional pattern distortion between the units, which makes the directions of the three antennas inconsistent. Figure 1 The consistency is obviously deteriorated, which seriously affects the accuracy of angle measurement.

[0004] Figure 1 It is a topological diagram of an existing UWB antenna unit. Figure 2 is a side view of the UWB antenna unit, Figure 3 and Figure 4 They are respectively the top view and bottom view of the UWB three-antenna device composed of the UWB antenna unit. Figure 3 Components 3-1, 3-2 and 3-3 are the feeding points in the top view, and components 3-4, 3-5 and 3-6 are the floors of the three antenna units. In the existing solution, on the one hand, the unit antennas are concentrated on one side of the opening, resulting in insufficient vertical coverage; on the other hand, due to the symmetry of the floors on both sides of the middle unit, pits appear in the front radiation pattern, which seriously affects the consistency of the three unit radiation patterns, and thus seriously deteriorates the angle measurement accuracy. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the existing technology and propose a design method for a UWB three-antenna device suitable for a miniaturized terminal. The present invention does not require additional devices and can achieve consistency in the directional pattern while ensuring the miniaturization of the antenna. It has great application value for the miniaturization of UWB terminal antennas with a 3D angle measurement function.

[0006] The embodiment of the present invention provides a design method for a UWB three - antenna device applicable to a miniaturized terminal, including:

[0007] For a UWB three - antenna device including three UWB antenna units, a slot corresponding to a quarter - wavelength is respectively opened on the floors on both sides of the middle UWB antenna unit; when the antenna is fed, the floor current flows from one side to the other along the edge path of the slot, and after passing through a path of half - wavelength, it reverses, so that the floor currents on both sides of the antenna flow in the same direction to the left at the same time; wherein, the UWB antenna unit includes: a bent region of the slot antenna for tuning the resonant frequency of the UWB antenna, two ground - return paths of the UWB antenna, and a reverse - extended unit for grounding.

[0008] The embodiment of the present invention also provides a design method for a UWB three - antenna device applicable to a miniaturized terminal, including:

[0009] For a UWB three - antenna device including three UWB antenna units, a slot less than one - eighth wavelength is respectively opened on the floors on both sides of the middle UWB antenna unit, and then a capacitor is connected across each slot; wherein, the current path around the slot is equivalent to an inductor, and the inductor and the capacitor are equivalent to a parallel LC circuit; the UWB antenna unit includes: a bent region of the slot antenna for tuning the resonant frequency of the UWB antenna, two ground - return paths of the UWB antenna, and a reverse - extended unit for grounding.

[0010] The features and beneficial effects of the present invention are as follows:

[0011] In the present invention, slots with a quarter - wavelength are respectively opened on both sides of the middle UWB antenna unit, so that the current paths close to both sides of the slot are reversed, and the floor currents at the mirror - image positions on both sides of the middle antenna flow in the same direction, avoiding the problem that the traditional scheme causes a pattern pit in the region directly in front of the antenna due to the reverse current on both sides, and effectively ensuring the consistency of the patterns of the three unit antennas. Further, by loading a small capacitor on both sides of the slot, the loop - slot current is equivalent to an inductor, and forms a parallel LC circuit with the loaded capacitor. This circuit constructs a "band - stop" filter in the UWB frequency band, effectively blocking the current path on the floor between the two antenna units. On the one hand, it improves the isolation between the two unit ports, and on the other hand, it avoids the reverse of the floor currents on both sides of the middle unit, resulting in a pattern pit.

[0012] Compared with the previous technical solutions, the present invention does not require additional devices, and can achieve pattern consistency on the basis of ensuring antenna miniaturization, which has great application value for the miniaturization of UWB terminal antennas with 3D angle - measuring functions. Description of the Drawings

[0013] Figure 1It is a topological diagram of an existing UWB antenna unit;

[0014] Figure 2 It is a side view of an existing UWB antenna unit;

[0015] Figure 3 It is a top view of a UWB three - antenna device composed of existing UWB antenna units;

[0016] Figure 4 It is a bottom view of a UWB three - antenna device composed of existing UWB antenna units;

[0017] Figure 5 It is a topological diagram of the UWB antenna unit according to the embodiment of the present invention;

[0018] Figure 6 It is a floor current distribution diagram of a UWB three - antenna device composed of existing UWB antenna units;

[0019] Figure 7 It is a UWB three - antenna device applicable to a miniaturized terminal and its floor current distribution diagram according to the embodiment of the present invention;

[0020] Figure 8 It is in the embodiment of the present invention corresponding to Figure 7 The comparison diagram of the radiation patterns in the XOZ plane before and after slits are opened on both sides of the middle UWB antenna unit of the device shown;

[0021] Figure 9 It is in the embodiment of the present invention corresponding to Figure 7 The comparison diagram of the consistency of the three UWB antenna units of the device shown;

[0022] Figure 10 It is another UWB three - antenna device applicable to a miniaturized terminal and its floor current distribution diagram according to the embodiment of the present invention;

[0023] Figure 11 It is in the embodiment of the present invention corresponding to Figure 10 The equivalent circuit model diagram of the slotted loading capacitor in the device shown;

[0024] Figure 12 It is in the embodiment of the present invention corresponding to Figure 10 The comparison diagram of the radiation patterns in the XOZ plane before and after the middle UWB antenna unit of the device shown is slotted;

[0025] Figure 13 It is in the embodiment of the present invention corresponding to Figure 10 The radiation pattern in the XOZ plane of the UWB three - antenna of the device shown. Detailed implementation manners

[0026] The present invention provides a design method for a UWB three - antenna device suitable for miniaturized terminals, which will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] An embodiment of the present invention provides a design method for a UWB three - antenna device suitable for miniaturized terminals. Among them, the UWB three - antenna device includes three UWB antenna units, and the topology diagram of each UWB antenna unit is as Figure 5 described. Among them, component 5 - 1 is the bending area of the slot antenna, which is used to tune the resonant frequency of the UWB antenna. Component 5 - 2 are the two ground - return paths of the UWB antenna, and component 5 - 3 is the reverse - extension unit of the ground - return. On the one hand, it can effectively expand the lobe width of the antenna in the vertical direction to achieve a larger FOV (Field of View) in the YOZ plane. Further, components such as MIC and infrared lamps can be placed at the opening position between the two ground - return positions of component 5 - 2, which can realize the miniaturized and integrated design of the UWB antenna with more components. The reverse - extension unit can be a conductor with a specific shape and size such as a rectangle or a semicircle.

[0028] Figure 6 is the floor - current distribution diagram of the UWB three - antenna device composed of existing UWB antenna units, where 6 - 1 indicates that the floor current is symmetrically distributed and flows in opposite directions on both sides.

[0029] Therefore, for a design method of a UWB three - antenna device suitable for miniaturized terminals in an embodiment of the present invention, the structure of the UWB three - antenna device suitable for miniaturized terminals is as Figure 7 shown, including: opening a quarter - wavelength slot corresponding to 8 GHz on the floors on both sides of the middle UWB antenna unit respectively; when the antenna is fed, the floor current flows from one side to the other along the edge path of the slot, and reverses after passing through a half - wavelength path. Therefore, the floor currents on both sides of the antenna flow in the same direction to the left at the same time, and the antenna has good radiation characteristics in the +Z - direction region of the XOZ plane. The comparison of the radiation patterns of the middle - unit antenna in the XOZ plane before and after slot - opening in this embodiment is as Figure 8 shown, Figure 8 in which the solid line corresponds to an existing UWB three - antenna device, and the dashed line corresponds to the UWB three - antenna device designed according to the method described in this embodiment. Among them, in the existing UWB three - antenna device, there is a concave pit of about 3 dB in the +Z - direction region of the XOZ plane of the UWB antenna radiation pattern. The comparison of the consistency of the three UWB antenna units in the UWB three - antenna device designed according to the method described in this embodiment is as Figure 9As shown in the figure, farfield (f = 8) in the figure represents the radiation patterns of three UWB antennas in the phi = 0 plane. It can be seen from the comparison that although the environment of the middle antenna element is significantly different from that of the two sides, this embodiment can effectively improve the pit problem of the middle unit antenna in the +Z direction region of the XOZ plane, and the radiation patterns of the three unit antennas have good consistency, and the maximum GAP is within 3 dB in the ±60° region, effectively ensuring the requirements of the 3D-PDOA algorithm for antenna consistency.

[0030] Furthermore, in order to reduce the influence of the slot and miniaturize the slot, the method of this embodiment can also be improved on the basis of the device as Figure 7 shown. The structure of the improved UWB three-antenna device is as Figure 10 shown; specifically, a slot less than one-eighth of the wavelength is respectively opened on the two sides of the floor of the middle UWB antenna element of the UWB three-antenna device, and then a small capacitor is connected across each slot, as Figure 10 shown in 10-1 and 10-2. The current path around the slot can be equivalent to an inductor, and the overall addition of a 0.5 pF capacitor can be equivalent to a parallel LC circuit. The equivalent circuit model of the slot loaded with a capacitor is as Figure 11 shown. In this embodiment, the radiation pattern of the middle unit antenna in the XOZ plane has an improvement and enhancement of about 4.5 dB in the +z direction by adopting the scheme of capacitive loaded slot, as Figure 12 shown. As Figure 13 shown, after adopting the method of loading the slot with a capacitor, the three UWB unit antennas also have good consistency, and the maximum GAP is within 2.7 dB in the FOV ±60 region, well meeting the requirements of the algorithm for antenna consistency.

[0031] The above-designed antenna radiation part can be any metal material with conductive properties such as LDS, FPC, and copper sheet; the embodiment is only used to illustrate the technical solution of this embodiment, rather than limiting it; although this patent has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of this patent.

Claims

1. A design method for a UWB three-antenna device suitable for a miniaturized terminal, characterized in that: include: For a UWB three-antenna device including three UWB antenna units, a slot corresponding to a quarter wavelength is opened on the floor on both sides of the middle UWB antenna unit respectively; when the antenna is fed, the floor current flows from one side to the other side along the slot edge path, and reverses after passing through a half-wavelength path, so that the floor currents on both sides of the antenna flow to the left in the same direction at the same time; wherein the UWB antenna unit includes: a bending area of ​​the slot antenna for tuning the resonant frequency of the UWB antenna, two return paths of the UWB antenna, and a reverse extension unit of the return path.

2. A design method for a UWB three-antenna device suitable for a miniaturized terminal, characterized in that: include: For a UWB three-antenna device including three UWB antenna units, a slot smaller than one-eighth of the wavelength is opened on the two side floors of the middle UWB antenna unit, and then a capacitor is connected across each slot; wherein the current path around the slot is equivalent to an inductor, and the inductor and the capacitor are equivalent to a parallel LC circuit; the UWB antenna unit includes: a bending area of ​​the slot antenna for tuning the resonant frequency of the UWB antenna, two return paths of the UWB antenna, and a reverse extension unit of the return path.

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