Vertically coupled feed circularly polarized annular directional radiation antenna

Abstract

The utility model relates to a vertically coupled feed circularly polarized annular directional radiation antenna, which comprises a first dielectric substrate and a second dielectric substrate which are arranged in parallel up and down, and a third dielectric substrate and a fourth dielectric substrate which are arranged between the first dielectric substrate and the second dielectric substrate in a crossed manner, an annular radiation patch and four square short circuit patches are printed on the upper surface of the first dielectric substrate; a T-shaped feed structure is printed on the lower surface of the first dielectric substrate; a reflecting plate is printed on the upper surface of the second dielectric substrate, and a rectangular slot and an in-slot rectangular patch are arranged in the middle of the reflecting plate; three metal patches in the vertical direction are printed on the surface of the third dielectric substrate; and two metal patches in the vertical direction are printed on the surface of the fourth dielectric substrate. The antenna provided by the utility model is small in size, good in performance, simple in processing, and suitable for RFID terminal products.

Description

TECHNICAL FIELD

[0001] The utility model relates to wireless communication technical field especially relates to a vertical coupling feed's circular polarization annular directional radiating antenna. BACKGROUND

[0002] Radio Frequency Identification (RFID) technology, as a kind of short-range wireless communication technology, realizes automatic identification and data reading of electronic tags by transmitting electromagnetic waves. The technology is initially mainly applied to military field, but with the rise of the concept of Internet of Things and the promotion of information age, it is widely applied in electronic toll collection system, warehousing logistics, medical care and other fields with the advantages of fast transmission speed, high security, dynamic change of tag data etc. At present, RFID technology is increasingly mature at home and abroad, and various RFID products are emerging, and in-depth study of its core technology not only promotes the innovation and development of the industry, but also brings people a more intelligent and convenient lifestyle.

[0003] RFID system is mainly composed of reader, electronic tag and computer system. The communication between reader and electronic tag relies on antenna to realize the transmission and reception of electromagnetic waves, and the performance of antenna directly affects the sensitivity of tag and the reading distance and efficiency of reader. Circularly polarized antenna is widely used in wireless communication system because it can effectively resist polarization mismatch and multipath interference attenuation. Most tag antennas are designed to be linearly polarized, and are placed in different positions, in order to ensure that the reader antenna can effectively identify the tag antenna in multiple directions, the reader antenna needs to be designed to be circularly polarized. In addition, in the design and application of RFID terminal products, the antenna is also required to have high gain, good directivity and as small size as possible to facilitate integration in the system. The widely used antennas in RFID include coil type antenna, dipole antenna and microstrip antenna, but their size is generally larger, which is difficult to meet the miniaturization requirement. Therefore, the research on small-sized and excellent performance RFID antenna has broad application prospect. SUMMARY

[0004] The utility model aims at providing a kind of circular polarization annular directional radiating antenna of vertical coupling feed;The antenna can be covered in the ultra-high frequency frequency band (920-925MHz) of our country RFID. Antenna adopts coupling feed mode, realizes the miniaturization design of antenna while keeping high performance, so that it can adapt to more application scenarios, especially in space limited occasions, such as small electronic equipment, smart card etc.

[0005] In order to achieve the above object, the technical scheme of the utility model is: a circularly polarized annular directional radiation antenna of vertical coupling feed, the antenna comprises first and second dielectric substrates placed in parallel from top to bottom, and third and fourth dielectric substrates placed in cross in the middle of the first and second dielectric substrates;

[0006] The upper surface of the first dielectric substrate is printed with an annular radiation patch and four square short-circuit patches; the lower surface of the first dielectric substrate is printed with a T-shaped feed structure to feed the annular radiation patch on the upper surface by coupling;

[0007] The upper surface of the second dielectric substrate is printed with a reflecting plate, and the reflecting plate is provided with a rectangular slot and a rectangular patch in the slot in the middle;

[0008] The third and fourth dielectric substrates are both wide H-shaped and placed in cross as the support structure of the antenna; the surface of the third dielectric substrate is printed with three metal patches in vertical direction, the metal patches on both sides of the third dielectric substrate are connected with the square short-circuit patches and the reflecting plate as transmission lines, and the metal patch close to the middle of the third dielectric substrate is used to connect the T-shaped feed structure and the rectangular patch in the slot; the surface of the fourth dielectric substrate is printed with two metal patches in vertical direction, and the two metal patches are on both sides of the fourth dielectric substrate and connected with the square short-circuit patches and the reflecting plate as transmission lines.

[0009] Preferably, the lower surface of the first dielectric substrate is printed with two T-shaped feed structures of different sizes, and the two T-shaped feed structures are placed vertically.

[0010] Preferably, the two T-shaped feed structures placed vertically are specifically that the T-shaped vertical parts of the two T-shaped feed structures intersect at a 90° angle at the center position of the lower surface of the first dielectric substrate.

[0011] Preferably, the length and width of the T-shaped feed structure satisfy that different coupling capacitances are generated between the annular radiation patch in two orthogonal directions by the two T-shaped feed structures of different sizes, two linear polarizations are excited, and the amplitudes of the two linear polarizations are equal and the phases are different by 90°, so that the circularly polarized radiation of the antenna is realized.

[0012] Preferably, the annular radiation patch is bent at four corners of the first dielectric substrate to form four grooves toward the center of the upper surface of the first dielectric substrate, and one square short-circuit patch is arranged at each groove.

[0013] Preferably, the antenna is fed by a coaxial line, the outer conductor of the coaxial line is connected with the reflecting plate of the second dielectric substrate, and the inner conductor of the coaxial line is connected with the rectangular patch in the slot of the second dielectric substrate.

[0014] Preferably, the upper end of the metal patch close to the middle of the third dielectric substrate is connected with the vertical part of the T-shaped feeding structure; and the lower end of the metal patch close to the middle of the third dielectric substrate is connected with the rectangular patch in the groove on the upper surface of the second dielectric substrate to connect the inner conductor of the coaxial line, so as to adjust the input impedance of the antenna.

[0015] Preferably, a square groove adapting to the thickness of the fourth dielectric substrate is arranged at the upper middle of the third dielectric substrate, and a square groove adapting to the thickness of the third dielectric substrate is arranged at the lower middle of the fourth dielectric substrate, so that the third dielectric substrate and the fourth dielectric substrate are clamped with each other through the two square grooves to realize the cross, fixation and connection of the two dielectric substrates.

[0016] Preferably, four square through grooves are arranged at the four corners of the first dielectric substrate and the second dielectric substrate respectively, and the vertical upper and lower protrusions of the H-shaped structure on the two sides of the third dielectric substrate and the fourth dielectric substrate are clamped with the square through grooves of the first dielectric substrate and the second dielectric substrate to realize the fixation and support of the antenna.

[0017] Preferably, the average value of the inner circumference and the outer circumference of the annular radiation patch of the antenna is less than or equal to the wavelength corresponding to the working frequency of the antenna.

[0018] Compared with the prior art, the antenna has the following beneficial effects:

[0019] The antenna has low cost, simple processing and stable performance, and is covered by the ultra-high frequency band (920-925MHz) in the RFID in China. The antenna adopts a coupling feeding mode, realizes the miniaturization design of the antenna while maintaining high performance, and can adapt to more application scenarios, especially in space-limited occasions, such as small electronic devices, smart cards and the like. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a perspective view of an embodiment of the utility model;

[0021] Figure 2 is a front view of an embodiment of the utility model;

[0022] Figure 3 is a structure schematic view of the upper surface of the first dielectric substrate of an embodiment of the utility model;

[0023] Figure 4 is a structure schematic view of the lower surface of the first dielectric substrate of an embodiment of the utility model;

[0024] Figure 5 is a structure schematic view of the upper surface of the second dielectric substrate of an embodiment of the utility model;

[0025] Figure 6This is a schematic diagram of the structure of the third dielectric substrate according to an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the structure of the fourth dielectric substrate according to an embodiment of the present invention;

[0027] Figure 8 This is a simulation result diagram of the reflection coefficient of an embodiment of this utility model;

[0028] Figure 9 This is a simulation result diagram of the shaft ratio of an embodiment of this utility model;

[0029] Figure 10 This is a simulation result of the radiation direction in the XOZ plane of an embodiment of this utility model;

[0030] Figure 11 This is a simulation result diagram of the gain of an embodiment of this utility model;

[0031] In the figure, 1-first dielectric substrate; 2-second dielectric substrate; 3-third dielectric substrate; 4-fourth dielectric substrate; 5-ring radiating patch; 6-square short-circuit patch; 7-square through slot of the first dielectric substrate; 8-square through slot of the second dielectric substrate; 9-T-shaped feeding structure; 10-vertically placed short-circuit patch; 11-vertically placed feeding patch; 12-reflector; 13-rectangular slot inside the reflector; 14-rectangular patch inside the slot of the reflector; 15-square slot of the third dielectric substrate; 16-square slot of the fourth dielectric substrate. Detailed Implementation

[0032] The following is in conjunction with the appendix Figures 1-11 The present invention will be described in detail below with specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0033] like Figures 1-7 As shown, this utility model proposes a vertically coupled fed circularly polarized ring directional radiation antenna, the antenna including a first dielectric substrate 1 and a second dielectric substrate 2 placed vertically in parallel, and a third dielectric substrate 3 and a fourth dielectric substrate 4 placed crosswise between the first dielectric substrate 1 and the second dielectric substrate 2.

[0034] The upper surface of the first dielectric substrate 1 is printed with an annular radiating patch 5 and four square short-circuit patches 6; the lower surface of the first dielectric substrate 1 is printed with a T-shaped feeding structure 9 to feed the annular radiating patch 5 on the upper surface through coupling.

[0035] The upper surface of the second dielectric substrate 2 is printed with a reflector 12, and the reflector 12 has a rectangular slot 13 and a rectangular patch 14 in the middle of the slot.

[0036] The third dielectric substrate 3 and the fourth dielectric substrate 4 are both wide H-shaped and are placed in cross as a support structure of the antenna; the surface of the third dielectric substrate 3 is printed with three metal patches in vertical direction, which are a vertically placed short circuit patch 10 and a vertically placed feeding patch 11, and two vertically placed short circuit patches 10 are located on both sides of the third dielectric substrate 3 as transmission lines connecting the square short circuit patch 6 and the reflector plate 12, and the vertically placed feeding patch 11 is close to the middle position of the third dielectric substrate 3 for connecting the T-shaped feeding structure 9 and the in-slot rectangular patch 14; the surface of the fourth dielectric substrate 4 is printed with two metal patches in vertical direction, which are both vertically placed short circuit patches 10, and the two vertically placed short circuit patches 10 are located on both sides of the fourth dielectric substrate as transmission lines connecting the square short circuit patch 6 and the reflector plate 12. The antenna has small size, good performance and simple processing, and is suitable for RFID terminal products.

[0037] In the embodiment, the lower surface of the first dielectric substrate 1 is printed with two T-shaped feeding structures 9 of different sizes, and the T-shaped feeding structures 9 are vertically placed.

[0038] In the embodiment, the two T-shaped feeding structures 9 are vertically placed in particular as follows: the T-shaped vertical parts of the two T-shaped feeding structures 9 intersect at a 90° angle at the center position of the lower surface of the first dielectric substrate 1.

[0039] In the embodiment, the lengths and widths of the two T-shaped feeding structures 9 are adjusted to make them different in size, so as to generate different coupling capacitances in two orthogonal directions and the annular radiation patch 5, excite two linear polarizations, and make the amplitudes of the two linear polarizations equal and the phases of the two linear polarizations differ by 90°, so as to realize circularly polarized radiation of the antenna.

[0040] In the embodiment, the annular radiation patch 5 is bent at four corners of the first dielectric substrate 1 to form four grooves towards the center of the upper surface of the first dielectric substrate 1, and one square short circuit patch 6 is arranged at each groove.

[0041] In the embodiment, the antenna is fed by a coaxial line, the outer conductor of the coaxial line is connected to the reflector plate 12 of the second dielectric substrate 2, and the inner conductor of the coaxial line is connected to the in-slot rectangular patch 14 of the second dielectric substrate 2.

[0042] In the embodiment, the upper end of the vertically placed feeding patch 11 is connected to the T-shaped vertical part of the T-shaped feeding structure 9, and the lower end of the vertically placed feeding patch 11 is connected to the in-slot rectangular patch 14 on the upper surface of the second dielectric substrate 2 to connect the inner conductor of the coaxial line and adjust the input impedance of the antenna.

[0043] In the embodiment, the third dielectric substrate 3 is provided with a square slot in the middle of the upper position, and the fourth dielectric substrate 4 is provided with a square slot in the middle of the lower position, and the third dielectric substrate 3 and the fourth dielectric substrate 4 are clamped with each other through the two square slots to realize the cross, fixation and connection of the two dielectric substrates.

[0044] In the embodiment, the first dielectric substrate 1 and the second dielectric substrate 2 are respectively provided with four square through slots, i.e., the first dielectric substrate square through slot 7 and the second dielectric substrate square through slot 8, and the H-shaped vertical upper and lower protrusions on the two sides of the third dielectric substrate 3 and the fourth dielectric substrate 4 are clamped with the first dielectric substrate square through slot 7 and the second dielectric substrate square through slot 8 to realize the fixation and support of the antenna.

[0045] In the embodiment, the average value of the inner circumference and the outer circumference of the annular radiation patch of the antenna is less than or equal to the wavelength corresponding to the working frequency of the antenna.

[0046] In the embodiment, the annular radiation patch 5, the square short circuit patch 6, the T-shaped feeding structure 9, the vertically placed short circuit patch 10, the vertically placed feeding metal patch 11, the reflector plate 12 and the rectangular patch in the reflector plate slot 14 of the antenna are metal materials, which can be copper or stainless steel.

[0047] In the embodiment, the circumference of the annular radiation patch 5, the size of the four square short circuit patches 6 and the distance between the annular radiation patch 5 and the square short circuit patch 6 are adjusted to adjust the impedance matching, so that the antenna works in the ultra-high frequency band (920-925MHz) in the RFID in China.

[0048] In the embodiment, the annular radiation patch 5, the square short circuit patch 6, the T-shaped feeding structure 9, the vertically placed short circuit patch 10, the vertically placed feeding metal patch 11, the reflector plate 12 and the rectangular patch in the reflector plate slot 14 of the antenna have a metal thickness, but the thickness is not limited. The annular radiation patch 5, the square short circuit patch 6, the T-shaped feeding structure 9, the reflector plate 12 and the rectangular patch in the reflector plate slot 14 are thin layers on the surface of the dielectric substrate by printing process.

[0049] The preferred embodiments of the utility model are described above with reference to the drawings, and the utility model is not limited by this. Any modification, equivalent replacement and improvement made by the person skilled in the art within the scope and essence of the utility model should be within the scope of the utility model.

Claims

1. A circularly polarized loop directional radiating antenna with vertical coupled feed, characterized by, The antenna comprises a first dielectric substrate and a second dielectric substrate arranged in parallel from top to bottom, and a third dielectric substrate and a fourth dielectric substrate arranged in cross between the first dielectric substrate and the second dielectric substrate; The upper surface of the first dielectric substrate is printed with a ring-shaped radiation patch and four square short-circuit patches; The lower surface of the first dielectric substrate is printed with a T-shaped feeding structure for feeding the ring-shaped radiation patch on the upper surface by coupling; The upper surface of the second dielectric substrate is printed with a reflecting plate, and a rectangular slot and a rectangular patch in the slot are arranged in the middle of the reflecting plate; The third dielectric substrate and the fourth dielectric substrate are both wide H-shaped and arranged in cross as a support structure of the antenna; the surface of the third dielectric substrate is printed with three metal patches in vertical direction, the metal patches on both sides of the third dielectric substrate are used as transmission lines to connect the square short-circuit patches and the reflecting plate, and the metal patch close to the middle of the third dielectric substrate is used to connect the T-shaped feeding structure and the rectangular patch in the slot; the surface of the fourth dielectric substrate is printed with two metal patches in vertical direction, and the two metal patches on both sides of the fourth dielectric substrate are used as transmission lines to connect the square short-circuit patches and the reflecting plate.

2. A circularly polarized loop directional antenna with vertical coupling feed according to claim 1, characterized in that, The lower surface of the first dielectric substrate is printed with two T-shaped feeding structures of different sizes, and the two T-shaped feeding structures are arranged vertically.

3. A circularly polarized loop directional antenna with vertical coupling feed according to claim 2, characterized in that, The two T-shaped feeding structures arranged vertically specifically intersect at the center of the lower surface of the first dielectric substrate with a 90° included angle between the T-shaped vertical parts of the two T-shaped feeding structures.

4. A circularly polarized loop directional antenna with vertical coupling feed according to claim 3, characterized in that, The length and width of the T-shaped feeding structure satisfy that different coupling capacitances are generated between the ring-shaped radiation patch in two orthogonal directions by the two T-shaped feeding structures of different sizes, two linear polarizations are excited, and the amplitudes of the two linear polarizations are equal and the phases are different by 90°, so as to realize circularly polarized radiation of the antenna.

5. The circularly polarized loop directional antenna of claim 1, wherein, The ring-shaped radiation patch is bent at four corners of the first dielectric substrate to form four recesses towards the center of the upper surface of the first dielectric substrate, and one square short-circuit patch is arranged at each recess.

6. The circularly polarized loop directional antenna of claim 1, wherein, The antenna is fed by a coaxial line, the outer conductor of the coaxial line is connected to the reflecting plate of the second dielectric substrate, and the inner conductor of the coaxial line is connected to the rectangular patch in the slot of the second dielectric substrate.

7. A circularly polarized loop directional antenna with vertical coupling feed according to claim 6, characterized in that, The upper end of the metal patch close to the middle of the third dielectric substrate is connected to the T-shaped vertical part of the T-shaped feeding structure, and the lower end of the metal patch close to the middle of the third dielectric substrate is connected to the rectangular patch in the slot of the upper surface of the second dielectric substrate to connect the inner conductor of the coaxial line.

8. The circularly polarized loop directional antenna of claim 1, wherein, A square slot with a thickness adapted to the fourth dielectric substrate is arranged at an upper position in the middle of the third dielectric substrate, and a square slot with a thickness adapted to the third dielectric substrate is arranged at a lower position in the middle of the fourth dielectric substrate, and the third dielectric substrate and the fourth dielectric substrate are clamped to each other through the two square slots to realize cross, fixation and connection of the two dielectric substrates.

9. The circularly polarized loop directional antenna of claim 1, wherein, Four square through-slots are arranged at four corners of the first dielectric substrate and the second dielectric substrate respectively, and the vertical upper and lower protrusions of the H-shaped on both sides of the third dielectric substrate and the fourth dielectric substrate are clamped to the square through-slots of the first dielectric substrate and the second dielectric substrate to realize fixation and support of the antenna.

10. The circularly polarized loop directional antenna of claim 1, wherein, An average of an inner circumference and an outer circumference of the annular radiating patch of the antenna is less than or equal to a wavelength corresponding to the operating frequency of the antenna. An average of an inner circumference and an outer circumference of the annular radiating patch of the antenna is less than or equal to a wavelength corresponding to the operating frequency of the antenna.

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