A broadband patch antenna based on multi-mode control

Abstract

A broadband patch antenna based on multi-mode control, comprising a dielectric substrate, an upper patch, a lower patch, a floor, a feeding structure, a coupling slot, a microstrip feeder, an air layer and a short-circuit frequency modulation structure to form a slot coupling feeding structure, wherein the dielectric substrate includes an upper dielectric substrate, a middle dielectric substrate and a lower dielectric substrate from top to bottom, the upper patch is arranged on the upper surface of the upper dielectric substrate, the lower patch is arranged on the upper surface of the middle dielectric substrate, the floor is arranged between the middle dielectric substrate and the lower dielectric substrate, the coupling slot is opened on the floor, the microstrip feeder is arranged on the lower surface of the lower dielectric substrate, the air layer is arranged between the middle dielectric substrate and the floor, and the short-circuit frequency modulation structure is evenly arranged between the upper dielectric substrate and the lower dielectric substrate. The antenna of the present invention has the purpose of simple structure, low profile, light weight, high impedance bandwidth and high gain bandwidth, as well as good directional pattern and polarization characteristics, and is suitable for a variety of different terminal application environments.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communications, and in particular to a broadband patch antenna based on multi-mode control. Background Art

[0002] Antennas are at the forefront of radio frequency communication systems and are important components for sending and receiving information. The quality of wireless communication is greatly affected by the quality of their radiation performance. Antennas are used in different fields, and their bandwidth, gain, direction, etc. vary to meet specific functional requirements. Patch antennas are widely used in wireless products, but the narrowband characteristics of their single-resonance radiation limit their use in broadband situations. Broadband patch antennas are commonly used in wireless communication systems such as Bluetooth, Wi-Fi, and GPS. They not only have the low profile of traditional patch antennas, simple structure, low processing cost, and easy integration with microwave circuits, but also can achieve high precision and miniaturization. Broadband patch antennas can be applied to more fields to better meet people's needs for high-speed, high-quality, and high-reliability data transmission and achieve high-quality communication. Therefore, research on broadband patch antennas has high economic value.

[0003] Based on the working principle, traditional broadband patch antennas can be divided into three categories. The first category is to change the structure of the antenna itself to achieve bandwidth. Increasing the cross-section of the patch antenna can increase its radiation resistance, thereby reducing the loss of reflected and scattered signals and improving the transmission efficiency of the antenna. At the same time, the increase in the cross-section of the antenna can also change the resonant frequency, which is convenient for matching with signals in different frequency bands and further expanding the bandwidth of the antenna. Reducing the dielectric constant of the medium can increase the edge field effect and radiation effect of the antenna, and the bandwidth and efficiency of the antenna will also increase. However, although the above methods can improve the bandwidth, they also make the antenna size larger and the gain lower. The second category is to introduce parasitic units or multi-layer structure coupling on the basis of the antenna itself to achieve broadband. The gain, bandwidth and other characteristics of the antenna are optimized by introducing parasitic units. For example, parasitic units such as inductors, capacitors or microstrip lines are introduced to improve the impedance bandwidth of the antenna, and new resonant modes are excited by electromagnetically coupling parasitic units. Parasitic elements can be installed vertically above the radiating patch to generate additional resonance to improve the bandwidth. Multi-layer structure coupling can achieve broadband by adopting slot coupling feeding, proximity coupling feeding or stacked patch configuration. However, the introduction of parasitic units and multi-layer structure coupling will increase the size or cross-section of the patch, resulting in high manufacturing difficulty and cost, which is not conducive to miniaturization. The third category is to improve the bandwidth through coupled feeding and various feeding networks. Coupled feeding can make the antenna have a relatively flat frequency response in a broadband range, thereby improving the bandwidth and performance of the antenna. The feeding network can use sequential phase feeding technology to generate broadband circularly polarized radiation to achieve broadband. The use of 90° phase delay lines and parasitic loops can also increase the circular polarization bandwidth, thereby achieving broadband. However, there are also shortcomings in achieving broadband using the above method. Although the impedance bandwidth of the antenna has increased, it cannot effectively broaden the gain bandwidth of the antenna itself. Moreover, the feeding network has a complex structure, is difficult to design, and has a high manufacturing cost, which is not conducive to production. Therefore, it is necessary to design a new broadband patch antenna based on multi-mode control to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to propose a broadband patch antenna based on multi-mode control to solve at least one technical problem existing in the above-mentioned prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A broadband patch antenna based on multi-mode control, comprising a dielectric substrate, an upper patch, a lower patch, a floor, a feeding structure, a coupling slot, a microstrip feed line, an air layer and a short-circuit frequency modulation structure to form a slot coupling feeding structure, wherein the dielectric substrate comprises an upper dielectric substrate, a middle dielectric substrate and a lower dielectric substrate in order from top to bottom, the upper patch is arranged on the upper dielectric substrate, the lower patch is arranged on the middle dielectric substrate, the upper patch is stacked on the lower patch, the floor is arranged between the middle dielectric substrate and the lower dielectric substrate, the coupling slot is opened on the floor, the microstrip feed line is arranged on the lower surface of the lower dielectric substrate, and the air layer is arranged between the middle dielectric substrate and the floor;

[0007] The short-circuit frequency modulation structure is arranged between the upper dielectric substrate and the lower dielectric substrate. The microstrip feed line excites the two working modes of the lower patch, and then the two working modes of the upper patch are excited through slot coupling feeding and the offset of the upper patch. By loading the short-circuit frequency modulation structure, several working modes are brought closer to form a wide impedance bandwidth characteristic.

[0008] Preferably, the upper patch and the lower patch are both set to TM10 and TM30 working modes, the microstrip feed line excites the TM10 and TM30 working modes of the lower patch, and excites the TM10 and TM30 modes of the upper patch through slot coupling feeding and the offset of the upper patch.

[0009] Preferably, the short-circuit frequency modulation structure is a short-circuit nail, and the short-circuit nail is arranged on the upper dielectric substrate, and the short-circuit nail is used to increase the resonant frequency of the TM10 working mode of the upper patch and the lower patch, and continuously approach the resonant frequency of the TM30 working mode.

[0010] Preferably, there are a plurality of short-circuit spikes, which are evenly arranged on the upper dielectric substrate and arranged in two rows, and the short-circuit spikes are distributed in a centrally symmetrical manner.

[0011] Preferably, the upper patch is a parasitic patch, the lower patch is a radiation patch, the upper patch is stacked on the lower patch, and two additional resonant modes are generated by coupling by performing a certain amount of horizontal offset in a direction orthogonal to the radiation electric field of the lower patch. The two working modes resonate on both sides of the TM10 mode frequency of the lower patch, so that the four resonant modes of the upper patch and the lower patch together form a broadband.

[0012] Preferably, the dielectric constant of the upper dielectric substrate is 2.08 and the thickness is 0.8 mm, the dielectric constant of the middle dielectric substrate is 2.08 and the thickness is 1.27 mm, and the dielectric constant of the lower dielectric substrate is 3.38 and the thickness is 0.813 mm.

[0013] Preferably, the upper patch is a rectangular radiation patch with a length of 1.03 vacuum wavelengths and a width of 0.365 vacuum wavelengths.

[0014] Preferably, the lower patch is a rectangular radiation patch with a length of 1.11 vacuum wavelengths and a width of 0.4 vacuum wavelengths.

[0015] Compared with the prior art, the broadband patch antenna based on multi-mode control provided by the present invention has the following beneficial effects:

[0016] 1. The present invention has a simple structure and low profile, and is suitable for various terminal environments. The simulation results show that the -10dB impedance bandwidth of the antenna is 2.28GHz-2.59GHz, the maximum actual gain at the center frequency of 2.385GHz is 7.2dB, and the 3dB gain bandwidth is 2.29GHz-2.73GHz. The antenna radiation pattern in the passband maintains good consistency, showing excellent broadband radiation characteristics.

[0017] 2. By setting the upper patch and the lower patch to excite two resonant modes, there are four resonant modes in total. Through multi-mode control, the four modes can be brought closer to each other, thereby forming a wide impedance bandwidth characteristic. The four modes are brought closer to the frequency position of the high-order mode, so that high gain characteristics can be achieved in a wide bandwidth range, improving the performance and availability of the antenna.

[0018] 3. The present invention has the advantages of small size, light weight and easy installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A 3D diagram of the antenna structure of the broadband patch antenna based on multi-mode control according to the present invention;

[0020] Figure 2 A top view of the antenna structure of the broadband patch antenna based on multi-mode control according to the present invention;

[0021] Figure 3 This is a side view of the broadband patch antenna structure based on multi-mode control according to the present invention;

[0022] Figure 4 It is an exploded view of the overall structure of the present invention;

[0023] Figure 5 This is a reflection coefficient simulation result diagram of the broadband patch antenna based on multi-mode control according to the present invention;

[0024] Figure 6 This is a graph of the gain-bandwidth simulation results of the broadband patch antenna based on multi-mode control according to the present invention;

[0025] Figure 7The 3D gain pattern of the center frequency of the broadband patch antenna based on multi-mode control described in the present invention (observation frequency: 2.385 GHz);

[0026] Figure 8 The actual gain 2D radiation pattern of the broadband patch antenna based on multi-mode control described in the present invention (observation frequency: 2.3 GHz, section: Phi = 0°, 90°);

[0027] Fig. 9 The actual gain 2D radiation pattern of the broadband patch antenna based on multi-mode control described in the present invention (observation frequency: 2.34 GHz, section: Phi = 0°, 90°);

[0028] Fig.10 The actual gain 2D radiation pattern of the broadband patch antenna based on multi-mode control described in the present invention (observation frequency: 2.38 GHz, section: Phi = 0°, 90°);

[0029] Fig.11 The actual gain 2D radiation pattern of the broadband patch antenna based on multi-mode control described in the present invention (observation frequency: 2.54 GHz, section: Phi = 0°, 90°). In the figure: 1, dielectric substrate; 2, upper patch; 3, lower patch; 4, floor; 5, feeding structure; 6, coupling gap; 7, microstrip feed line; 8, air layer; 9, short-circuit frequency modulation structure (short-circuit spike). DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0031] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship 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 a limitation on the present invention.

[0032] Example 1

[0033] Please see attached Figure 1-4As shown, this embodiment provides a broadband patch antenna based on multi-mode control, which consists of a dielectric substrate 1, an upper patch 2, a lower patch 3, a floor 4, a feeding structure 5, a coupling slot 6, a microstrip feed line 7, an air layer 8 and a short-circuit frequency modulation structure 9 to form a slot-coupled feeding structure. The dielectric substrate 1 includes an upper dielectric substrate, a middle dielectric substrate and a lower dielectric substrate from top to bottom, the upper patch 2 is arranged on the upper dielectric substrate, the lower patch 3 is arranged on the middle dielectric substrate, the floor 4 is arranged between the middle dielectric substrate and the lower dielectric substrate, the coupling slot 6 is opened on the floor 4, the microstrip feed line is arranged on the back of the floor, the feeding structure 5 is arranged on the lower dielectric substrate 13, and the floor 4 is a metal floor. The air layer 8 is arranged between the middle dielectric substrate 12 and the floor 4, the short-circuit frequency modulation structure is specifically arranged as a short-circuit spike structure, and the short-circuit spikes 9 are evenly arranged between the upper dielectric substrate and the lower dielectric substrate; the microstrip feed line 7 excites the TM10 and TM30 modes of the lower patch 3, and excites the TM10 and TM30 modes of the upper patch 2 through slot coupling feeding and the offset of the upper patch 2.

[0034] In this embodiment, a slot-coupled feeding structure is provided, and the slot-coupled feeding structure can effectively couple the energy on the microstrip feed line 7 to the antenna radiator, thereby realizing effective energy transmission. This can reduce reflection and power loss to a certain extent and improve feeding efficiency. The present invention is based on the multi-mode resonance of the patch antenna and the principle of parasitic coupling, and constructs a model of "loaded short-circuit nail + parasitic offset patch". The slot-coupled antenna can only excite the odd mode and completely eliminate the resonance of the even mode. The upper patch 2 and the lower patch 3 both excite two resonant modes, a total of four resonant modes. Through multi-mode regulation, the four modes can be brought closer, thereby forming a wide impedance bandwidth characteristic, so that the antenna can work normally in a wider frequency range, which is conducive to maintaining the stability of the receiving and transmitting signals. In addition, the present invention also realizes a wide gain bandwidth. The present invention brings the four modes closer to the frequency position of the higher-order mode, so that high gain characteristics can be achieved within a wide frequency band, thereby improving the performance and availability of the antenna. This model also has the advantages of small size, light weight and easy installation.

[0035] In a specific embodiment, Figure 1-4 As shown, the number of the short-circuit pins 9 is eight and they are evenly arranged on both sides of the upper dielectric substrate.

[0036] In this embodiment, the function of the short-circuit spike 9 is to increase the resonance frequency of TM10 and continuously approach the resonance frequency of TM30.

[0037] In a specific embodiment, the dielectric constant of the upper dielectric substrate is 2.08 and the thickness is 0.8 mm, the dielectric constant of the middle dielectric substrate is 2.08 and the thickness is 1.27 mm, and the dielectric constant of the lower dielectric substrate is 3.38 and the thickness is 0.813 mm. The upper patch 2 is a rectangular radiation patch with a length of 1.03 vacuum wavelengths and a width of 0.365 vacuum wavelengths. The lower patch 3 is a rectangular radiation patch with a length of 1.11 vacuum wavelengths and a width of 0.4 vacuum wavelengths.

[0038] like Figure 5 As shown, it can be found that the four resonant frequencies are 2.299 GHz, 2.335 GHz, 2.385 GHz, and 2.543 GHz, and the -10 dB impedance bandwidth is 2.28 GHz-2.59 GHz.

[0039] like Figure 6 As shown, the 3dB gain bandwidth is 2.29GHz-2.73GHz.

[0040] like Figure 7 As shown, it can be found that the maximum practical gain is 7.2dB.

[0041] like Figures 8 to 11 As shown, it can be found that the radiation effect of the antenna is good.

[0042] The working process of the present invention is as follows:

[0043] The antenna excites two modes of the lower patch 3 by the microstrip feed line 7, and then excites two modes of the upper patch 2 through slot coupling feeding and the offset of the upper patch 2. By analyzing the current distribution of the four modes, the loading short-circuit nail 9 is used to bring several modes closer, thereby improving the impedance bandwidth and gain bandwidth of the patch antenna.

[0044] In summary, the present invention is based on the multi-mode resonance and parasitic coupling principle of patch antennas, and by constructing a "loaded short-circuit pin + parasitic offset patch" model, the broadband characteristics of four mode frequencies are achieved in a very small antenna volume without the need for an additional feeding network. Generally speaking, patches operating in TM10 and TM30 modes can produce wide-edge radiation with the same polarization. The radiating patch, i.e., the lower patch 3, is loaded with four pairs of centrally symmetrical short-circuit pins to increase the frequency of the TM10 mode, so that it is close to the TM30 mode frequency to form a broadband. The parasitic patch, i.e., the upper patch 2, is stacked on the radiating patch, and two additional resonant modes are generated by coupling by a certain amount of horizontal offset in a direction orthogonal to the radiation electric field of the radiating patch. These two modes resonate on both sides of the TM10 mode frequency of the lower patch 3. These four resonant modes together form a broadband, with a -10dB impedance bandwidth of 2.28GHz-2.59GHz (about 13%), and good gain and directivity in the band, while the height of the antenna is only 0.037 free space wavelengths. In addition, the slot-coupled feeding method adopted in this invention makes it easy to achieve impedance matching and bandwidth expansion and improves the feeding efficiency and performance of the antenna. Fine-tuning the position of the parasitic patch can achieve matching of additional modes. The low-profile design is suitable for a variety of terminal devices and has great application potential.

[0045] Embodiment 2:

[0046] The short-circuit nail 9 can be replaced with a slit to achieve the mode of pulling the lower patch 3 closer. The rest is completely consistent with the first embodiment.

[0047] Embodiment 3:

[0048] The slot coupling feeding structure can be replaced by a dual coaxial differential feeding structure. The rest is the same as that of Embodiment 1 and Embodiment 2.

[0049] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A broadband patch antenna based on multi-mode control, characterized in that: The invention comprises a dielectric substrate (1), an upper patch (2), a lower patch (3), a floor (4), a feeding structure (5), a coupling gap (6), a microstrip feed line (7), an air layer (8) and a short-circuit frequency modulation structure (9); the dielectric substrate (1) comprises, from top to bottom, an upper dielectric substrate (11), a middle dielectric substrate (12) and a lower dielectric substrate (13); the upper patch (2) is arranged on the upper surface of the upper dielectric substrate (11); the lower patch (3) is arranged on the middle dielectric substrate (12). The upper surface of the board (12), the upper patch (2) is stacked on the lower patch (3), the floor (4) is arranged between the middle dielectric substrate (12) and the lower dielectric substrate (13), the coupling gap (6) is opened on the floor (4), the microstrip feed line (7) is arranged on the lower surface of the lower dielectric substrate (13), the feeding structure (5) is arranged on the lower dielectric substrate (13), and the air layer (8) is arranged between the middle dielectric substrate (12) and the floor (4); The short-circuit frequency modulation structure (9) is arranged between an upper dielectric substrate (11) and a lower dielectric substrate (13); the microstrip feed line (7) excites two working modes of the lower patch (3); and then excites two working modes of the upper patch (2) through slot coupling feeding and the offset of the upper patch (2); and the several working modes are brought closer together by loading the short-circuit frequency modulation structure (9), thereby forming a wide impedance bandwidth characteristic; The upper patch (2) is a parasitic patch, and the lower patch (3) is a radiation patch. The upper patch (2) is stacked on the lower patch (3), and two additional resonance modes are generated by coupling through a certain amount of horizontal shift in a direction orthogonal to the radiation electric field of the lower patch (3). The two working modes resonate on both sides of the TM10 mode frequency of the lower patch (3), so that the four resonance modes of the upper patch (2) and the lower patch (3) together form a broadband.

2. The broadband patch antenna based on multi-mode control according to claim 1, characterized in that: The upper patch (2) and the lower patch (3) are both set to two working modes, TM10 and TM30; the microstrip feed line (7) excites the two working modes, TM10 and TM30, of the lower patch (3); and the two modes, TM10 and TM30, of the upper patch (2) are excited through slot coupling feeding and the offset of the upper patch (2).

3. The broadband patch antenna based on multi-mode control according to claim 2, characterized in that: The short-circuit frequency modulation structure (9) is a short-circuit nail. The short-circuit nail is arranged between the upper dielectric substrate (11) and the lower dielectric substrate (13), and the upper and lower ends of the short-circuit nail are connected to the lower patch (3) and the floor (4) in sequence. The short-circuit nail is used to increase the resonance frequency of the TM10 working mode of the upper patch (2) and the lower patch (3), and continuously approach the resonance frequency of the TM30 working mode.

4. The broadband patch antenna based on multi-mode control according to claim 3, characterized in that: There are a plurality of short-circuit spikes, which are evenly arranged between the upper dielectric substrate and the lower dielectric substrate and arranged in two rows, and the short-circuit spikes are centrally symmetrical.

5. The broadband patch antenna based on multi-mode control according to claim 1, characterized in that: The dielectric constant of the upper dielectric substrate (11) is 2.08 and the thickness is 0.8 mm, the dielectric constant of the middle dielectric substrate (12) is 2.08 and the thickness is 1.27 mm, and the dielectric constant of the lower dielectric substrate (13) is 3.38 and the thickness is 0.813 mm.

6. The broadband patch antenna based on multi-mode control according to claim 1, characterized in that: The upper patch (2) is a rectangular radiation patch with a length of 1.03 vacuum wavelengths and a width of 0.365 vacuum wavelengths.

7. The broadband patch antenna based on multi-mode control according to claim 1, characterized in that: The lower patch (3) is a rectangular radiation patch with a length of 1.11 vacuum wavelengths and a width of 0.4 vacuum wavelengths.

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