阅读说明：本技术 应用于无线局域网wlan频段的带内陷波宽带天线 (In-band notch broadband antenna applied to WLAN frequency band ) 是由 周涛 迟梦娇 宋开新 石仁刚 程知群 潘勉 董志华 李世琦 刘国华 刘杰 高扬华 于 2021-06-07 设计创作，主要内容包括：本发明公开应用于无线局域网WLAN频段的带内陷波宽带天线。包括介质基板；辐射贴片,设置在介质基板的上表面；微带馈线,设置在介质基板的上表面,且与辐射贴片相连；金属接地板,设置在介质基板的下表面；其中：所述辐射贴片内开有第一槽,第一槽内设有轴对称的两辐射枝节；两辐射枝节不接触；每个辐射枝节均包括第一枝节、与第一枝节垂直设置的第二枝节；第一枝节的一端与辐射贴片连接,另一端与第二枝节连接；所述金属接地板刻蚀有第二槽,第二槽的位置与微带馈线相对应。通过调整第一槽底边离馈电端口的距离d进而调控VSWR的峰值大小；通过调整两辐射枝节之间的距离g进而调控VSWR的峰值位置。(The invention discloses an in-band notch broadband antenna applied to a WLAN frequency band. Comprises a dielectric substrate; the radiation patch is arranged on the upper surface of the dielectric substrate; the microstrip feeder line is arranged on the upper surface of the dielectric substrate and is connected with the radiation patch; the metal grounding plate is arranged on the lower surface of the dielectric substrate; wherein: a first groove is formed in the radiation patch, and two axisymmetric radiation branches are arranged in the first groove; the two radiation branches are not contacted; each radiation branch comprises a first branch and a second branch which is perpendicular to the first branch; one end of the first branch is connected with the radiation patch, and the other end of the first branch is connected with the second branch; and a second groove is etched on the metal grounding plate, and the position of the second groove corresponds to the position of the microstrip feeder line. The peak value of the VSWR is regulated and controlled by adjusting the distance d between the bottom edge of the first groove and the feed port; the peak position of the VSWR is regulated and controlled by adjusting the distance g between the two radiation branches.)

1. In-band notch broadband antenna applied to WLAN frequency band, characterized by comprising:

a dielectric substrate;

the radiation patch is arranged on the upper surface of the dielectric substrate;

the microstrip feeder line is arranged on the upper surface of the dielectric substrate and is connected with the radiation patch;

the metal grounding plate is arranged on the lower surface of the dielectric substrate;

wherein:

a first groove is formed in the radiation patch, and two axisymmetric radiation branches are arranged in the first groove; the two radiation branches are not contacted;

each radiation branch comprises a first branch and a second branch which is perpendicular to the first branch; one end of the first branch is connected with the radiation patch, and the other end of the first branch is connected with the second branch;

and the metal grounding plate is etched with a second groove.

2. The in-band notch broadband antenna for WLAN frequency band according to claim 1, wherein the connection point of the first branch and the second branch is the center of the second branch.

3. The in-band notch broadband antenna applied to the WLAN frequency band of claim 1, wherein the two ends of the second branch are respectively connected with a tapered branch, and the narrower end of the tapered branch is connected with the second branch.

4. The in-band notch broadband antenna for WLAN frequency band according to claim 1, wherein the connection end of the radiation patch and the microstrip feed line adopts a tapered structure, wherein the narrower end is connected to the microstrip feed line.

5. The in-band notch broadband antenna for WLAN frequency band according to claim 1, wherein the end of the radiating patch far from the microstrip feed line is of a tapered structure, and the narrower end is far from the microstrip feed line.

6. An in-band notch broadband antenna for WLAN frequency band according to claim 1 characterized by that the radiating patch has a length satisfying 1/2 λ, where λ represents wavelength.

7. The in-band notch broadband antenna for WLAN frequency band according to claim 1, wherein the microstrip feed line is identical to the length of the metal ground plate.

8. The in-band notch broadband antenna for WLAN frequency bands of wireless local area networks as claimed in claim 1, wherein the width of the second slot is larger than the width of the microstrip feed line.

9. The in-band notch broadband antenna for WLAN frequency band according to claim 1 wherein the width of the radiating patch is larger than the width of the radiating stub.

10. The in-band notch broadband antenna applied to the WLAN frequency band of claim 1, wherein the VSWR peak value is adjusted by adjusting the distance d from the bottom edge of the first slot to the feeding port; the peak position of the VSWR is regulated and controlled by adjusting the distance g between the two radiation branches.

Technical Field

The invention belongs to the technical field of antennas, relates to the technical field of broadband notch antennas, and particularly relates to an antenna with a notch function.

Background

In the 60's of the 20 th century, ultra wide band (ultrawide band) began to appear, which initially described the transient characteristics of a microwave network with an impulse response on the order of nanoseconds to microseconds, and could be used for indoor positioning at close range, and then was used in the design of broadband antennas. The existing broadband technology has the advantages of high transmission rate, strong anti-interference capability, strong anti-multipath effect capability and the like, and is widely applied to the fields of wireless sensors, high-precision positioning, radars and the like. However, in a wide frequency band, other communication frequency bands exist, so that interference is generated in a communication process, and the transmission quality of signals is affected.

In order to solve the above problems, many solutions have been proposed by researchers. For example, CN212587713U discloses an antenna with a notch function, which includes a substrate, and an oscillator and a microstrip feed line located on the upper surface of the substrate, and a floor located on the lower surface of the substrate; the floor is in a semi-elliptical shape; the oscillator is provided with a gap, the gap is in an Contraband shape with an opening pointing to the microstrip feeder line, and the gap is positioned in the middle of the oscillator, so that the stop line can realize a trap function on a frequency band with interference in ultra-wideband communication. However, since only the center frequency of the notch is given as 5.8Ghz, it cannot be observed whether the notch covers the whole WLAN range (WLAN:5.15-5.35Ghz,5.725-5.825Ghz), which makes the practical application limited. For another example, CN 111478027a discloses a broadband double-notch ultra-wideband antenna, which includes a dielectric substrate, a radiating element, a microstrip feed line, and a metal ground plate. The antenna has small size and simple structure, can cover the whole frequency band of the WLAN, but because the notch of the antenna is too wide, signals at other frequencies can be interfered.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an in-band notch broadband antenna applied to a WLAN frequency band, which has the advantages of miniaturization, simple structure and capability of covering the whole frequency band of the WLAN by a notch frequency band.

In order to achieve the purpose, the invention adopts the technical scheme that:

in-band notch broadband antenna applied to WLAN frequency band, comprising:

a dielectric substrate;

the radiation patch is arranged on the upper surface of the dielectric substrate;

the microstrip feeder line is arranged on the upper surface of the dielectric substrate and is connected with the radiation patch;

the metal grounding plate is arranged on the lower surface of the dielectric substrate;

wherein:

a first groove is formed in the radiation patch, and two axisymmetric radiation branches are arranged in the first groove; the two radiation branches are not contacted;

each radiation branch comprises a first branch and a second branch which is perpendicular to the first branch; one end of the first branch is connected with the radiation patch, and the other end of the first branch is connected with the second branch;

and a second groove is etched on the metal grounding plate, and the position of the second groove corresponds to the position of the microstrip feeder line.

Preferably, the connection point of the first branch and the second branch is the center of the second branch;

preferably, two ends of the second branch are respectively connected with a gradual change branch, wherein the narrower end of the gradual change branch is connected with the second branch;

preferably, the connection end of the radiation patch and the microstrip feeder line adopts a gradual change structure, wherein the narrower end is connected with the microstrip feeder line;

preferably, the end of the radiation patch far away from the microstrip feeder line adopts a gradual change structure, wherein the narrower end is far away from the microstrip feeder line;

preferably, the radiating patch has a length of 1/2 λ, where λ represents a wavelength.

Preferably, the microstrip feed line and the metal ground plate have the same length.

Preferably, the width of the second slot is greater than the width of the microstrip feed line.

Preferably, the width of the radiating patch is greater than the width of the radiating stub.

Compared with the prior art, the invention has the following advantages:

the notch antenna applied to the WLAN frequency band of the wireless local area network, provided by the invention, is used for increasing an extra path of current, increasing the effective current length of the antenna and generating resonant frequency by digging grooves on the metal grounding plate and the radiation patch so as to realize the notch antenna just covering the WLAN frequency band, and signals at other frequency bands are not interfered. The branches added in the first slot enable the whole radiating patch to be similar to an ELC resonant unit, the ELC is excited by flowing current coupling, and the strip widening around the ELC is used for weakening the resonance and reducing the inductance effect. The two ends of the radiation patch adopt the gradual change structure, so that the half-wavelength current path is reduced, the gain is reduced, the bandwidth is increased, and the ultra-wideband is better realized.

Drawings

FIG. 1 is a schematic diagram of the overall structure of an embodiment of the present invention;

fig. 2(a) is a top view of the radiation patch structure on the upper surface of the dielectric substrate of the present invention, and fig. 2(b) is a branch structure in the empty slot of the radiation patch of the present invention;

FIG. 3 is a structural view of a metal floor according to an embodiment of the present invention;

FIG. 4 is a graph of a simulation of the reflection coefficient for an embodiment of the present invention;

FIG. 5 is a graph of a simulation of the standing wave ratio VSWR of an embodiment of the present invention;

fig. 6(a) and (b) are H-plane and E-plane radiation patterns at 6Ghz for an embodiment of the invention.

Detailed Description

The invention is described in further detail below with reference to the following figures and specific examples:

referring to fig. 1, the present invention provides a notch broadband antenna, as shown in fig. 1, including:

a dielectric substrate 4;

the radiation patch 1 is arranged on the upper surface of the dielectric substrate;

the microstrip feeder line 2 is arranged on the upper surface of the dielectric substrate and connected with the radiation patch;

a metal grounding plate 3 arranged on the lower surface of the dielectric substrate;

the length of the microstrip feeder line is consistent with that of the metal grounding plate.

The top view of the radiating patch 1 and the microstrip feed line 2 on the upper surface of the dielectric substrate of the invention is shown in fig. 2(a), and the schematic structure of the first slot and the radiating branch on the radiating element is shown in fig. 2 (b).

A first groove is formed in the radiation patch, and two axisymmetric radiation branches are arranged in the first groove; the two radiation branches are not contacted;

each radiation branch comprises a first branch and a second branch which is perpendicular to the first branch; one end of the first branch is connected with the radiation patch, and the other end of the first branch is connected with the second branch;

as shown in fig. 3, a second slot is etched in the metal ground plate, and the position of the second slot corresponds to the position of the microstrip feed line;

the connection point of the first branch knot and the second branch knot is the center of the second branch knot;

the two ends of the second branch are respectively connected with a gradual change branch, wherein the narrower end of the gradual change branch is connected with the second branch;

the connection end of the radiation patch and the microstrip feeder line adopts a gradual change structure, wherein the narrower end is connected with the microstrip feeder line;

the end of the radiation patch far away from the microstrip feeder line adopts a gradual change structure, wherein the narrower end is far away from the microstrip feeder line;

the length of the radiating patch satisfies 1/2 λ, where λ represents a wavelength;

the length of the microstrip feeder line is consistent with that of the metal grounding plate;

the width of the second slot is larger than that of the microstrip feeder line;

the width of the radiation patch is larger than that of the radiation branch.

In the embodiment of the invention, the connecting end of the radiation patch and the microstrip feeder line adopts a gradual change structure, and the shape is obtained by cutting the angle of the radiation patch, so that the aim is to reduce the half-wavelength current path, reduce the gain, increase the bandwidth and realize the miniaturization of the antenna;

the microstrip feed line has a rectangular structure, the width of which is given by the formula (1) (2), and the characteristic impedance is usually set to 50 Ω. One end of the microstrip feeder line is connected with the radiation patch, so that the current path is increased, the radiation efficiency of the antenna is improved, and broadband matching is realized. And grooves and branch sections are formed on the radiation patch, so that an additional path of current can be increased, resonance frequency is generated, and the trap characteristic is realized.

The metal grounding plate is provided with the groove, so that the radiation efficiency of the antenna is improved, the impedance matching changes slowly at the central resonance frequency point, and the impedance bandwidth of the antenna can be effectively expanded.

The dielectric substrate of the antenna is made of a material with the dielectric constant of 2.65 and the thickness of 0.8 mm; the thickness of the radiation patch and the metal grounding plate is 0.018 mm.

The first groove on the radiation patch is in a gourd shape and has a symmetrical structure; the two radiation branches in the first groove respectively comprise a first branch and a second branch which is perpendicular to the first branch; one end of the first branch is connected with the radiation patch, and the other end of the first branch is connected with the second branch; the first branch is a vertical patch, and the second branch is a horizontal patch.

In one embodiment of the invention, d is the distance from the lower edge of the first slot to the feed point, the whole radiating patch and the branch in the slot are equivalent to an ELC structure, the ELC structure is excited by the coupling of flowing current, when the radiating patch is close to the outer edge of the patch, the coupling effect is obvious, the stop band cut-off is good, when the slot moves upwards, the coupling effect is weakened, the resonator cannot be effectively excited, the stop band cut-off is not obvious, and therefore the peak value of the VSWR can be changed by adjusting d; r1 determines the length of current path, and the notch range can be changed by adjusting r 1; two radiation branches in the first groove are in an axisymmetric structure, when resonance occurs, two second branches gather charges with opposite polarities, electric field effect between the charges generates capacitance, the size of the capacitance is determined by a gap g between the two second branches, and therefore the size of the capacitance is adjusted, and a peak value can move left and right. By varying these parameter values, different notch frequency bands are generated.

TABLE 1 trap antenna structure size

Parameter(s)	Size (mm)	Parameter(s)	Size (mm)
				W	32	r1	3
L	24	W2	2.2
				d	15	x	1.2
gr	11	g	0.7
				L2	6.6	W3	0.6
r	6	C	3.7
				L1	4.2	W1	3

The parameter values shown in table 1 are specific parameter values of an antenna embodiment, the length of the dielectric substrate is L, the width of the dielectric substrate is W, the length of the radiating patch satisfies 1/2 wavelengths, and the width of the radiating patch is given by formula (1); the end, far away from the microstrip feed line, of the radiation patch is semicircular, the radius of the radiation patch is r, the middle part of the gradual change structure at the two ends of the radiation patch is of a rectangular structure, and the length of the radiation patch is L2; the calabash-shaped first slot in the radiation patch consists of an upper half part and a lower half part, the radiuses of the upper half part and the lower half part are both r1, the distance from the bottom edge of the first slot to the feed port is d, the gap distance between the two second branches is g, the width of the microstrip feed line is W2, the width of the microstrip feed line is calculated according to the formulas (2) - (3), and the length of the microstrip feed line is gr; the widths of the first branch and the second branch are W3, and the length of the second branch is x; the length of the gradual change structure connected with the second branch is (c/2-x), the length of the first branch is 0.05 × d + r1, the width of the second groove of the metal grounding plate is W1, and the length of the second groove is L1.

Wherein epsilon_rFor the dielectric constant, f is the resonant frequency, c is the speed of light, and w is the width of the radiating patch.

Wherein epsilon_eIs dielectric constant, w is width of microstrip feed line, d is thickness of dielectric plate, Z is characteristic impedance, and is 50 Ω, ε_rIs the dielectric constant.

The technical effects of the invention are further explained by combining simulation experiments:

FIG. 4 is a simulation graph of the reflection coefficient of the embodiment of the present invention, in which, when the reflection coefficient is less than or equal to-10 dB, the antenna generates notch in the frequency band of 5.1-5.9 Ghz, covering the whole WLAN frequency band (5.15-5.35Ghz, 5.725-5.825 Ghz); FIG. 5 is a graph of a simulation of the standing wave ratio VSWR of an embodiment of the present invention; as can be seen from fig. 4 and 5, the antenna provided by the embodiment of the present invention meets the requirement of achieving the WLAN band notch.

Fig. 6(a) and (b) are H-plane and E-plane radiation patterns at 6Ghz for an embodiment of the invention.

In summary, the above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Based on the present disclosure, modifications, improvements, etc. in the parameters and structures may be made after understanding the present disclosure and design principles, and such modifications and improvements are still within the scope of the present disclosure.