Four-band directional vehicle antenna

Abstract

A four-frequency-band directional vehicle-mounted antenna comprises a metal floor, a dielectric substrate, a slotted radiation patch unit, a coaxial feeding structure and two T-shaped monopole branches. The slotted radiation patch unit is a circular patch, four L-shaped slots are formed on the circumferential edge of the circular patch, the L-shaped slots can change the current distribution of the high-order mode of the circular patch, reshape the irregular conical beam, and form a directional inclined double beam; meanwhile, the introduction of the L-shaped slots can increase the current path and thus reduce the resonance frequency of high frequency. The two T-shaped monopole branches are oppositely and equally spaced on the two sides of the slotted radiation patch unit, used to excite the equivalent magnetic current on the two end edges of the circular patch, and the equivalent magnetic current is symmetric about the center, thus forming a directional inclined double beam with higher gain value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antennas, in particular to a four-frequency directional vehicle-mounted antenna. BACKGROUND

[0002] In recent years, with the continuous development of wireless communication standards, multi-frequency has become a necessary requirement for more and more electronic devices. At the same time, as a means of transportation, cars are constantly being replaced to meet the growing needs of people's driving experience. While paying attention to travel safety, people's entertainment needs also need to be taken into account, so more and more wireless functions such as WIFI, Bluetooth, global navigation positioning, V2X, etc. are introduced into car electronic devices. Considering the appearance factor, these communication antennas often need to be designed as small-size planar structures to facilitate installation and reduce costs. SUMMARY

[0003] The purpose of the present application is to provide a four-frequency directional vehicle-mounted antenna that can exhibit different beam characteristics at four different frequency bands and meet the radiation performance of different frequency bands.

[0004] The purpose of the present application is achieved by such a technical solution, which includes a metal floor and a dielectric substrate attached to the upper surface of the metal floor. The antenna also includes a slotted radiation patch unit, a coaxial feed structure, and two T-shaped monopole stubs.

[0005] The slotted radiation patch unit is parallel to the metal floor and is arranged on the upper surface of the dielectric substrate.

[0006] The coaxial feed structure has an inner conductor connected to the slotted radiation patch unit and an outer conductor connected to the metal floor.

[0007] The two T-shaped monopole stubs are arranged on both sides of the slotted radiation patch unit with equal gaps, and are used to excite the equivalent magnetic current on the two end edges of the circular patch.

[0008] Further, the slotted radiation patch unit is a circular patch, and four L-shaped slots are formed on the circumferential edge of the circular patch.

[0009] Further, the T-shaped monopole stubs each include a shorting post and an arc-shaped horizontal arm, one end of the shorting post is in contact with the horizontal arm, and the other end is connected to the ground.

[0010] The two arc-shaped horizontal arms are located on both sides of the circular patch and are parallel to the circumference of the circular patch.

[0011] Further, the four L-shaped slots are a first L-shaped slot, a second L-shaped slot, a third L-shaped slot, and a fourth L-shaped slot.

[0012] The first L-shaped slot and the second L-shaped slot are equal in size and correspond to the positions of the two ends of one horizontal arm, and the third L-shaped slot and the fourth L-shaped slot are equal in size and correspond to the positions of the two ends of the other horizontal arm.

[0013] The first L-shaped slot and the second L-shaped slot are symmetric about the central axis X of the antenna, the third L-shaped slot and the fourth L-shaped slot are symmetric about the central axis X of the antenna, the first L-shaped slot and the third L-shaped slot are symmetric about the other central axis Y of the antenna, and the second L-shaped slot and the fourth L-shaped slot are symmetric about the other central axis Y of the antenna.

[0014] Further, the first L-shaped slot and the second L-shaped slot each include a first rectangular strip and a first arc-shaped strip, one end of the first rectangular strip is provided at the circumferential edge of the circular patch, the other end extends into the circular patch and is connected to one end of the first arc-shaped strip.

[0015] The third L-shaped slot and the fourth L-shaped slot each include a second rectangular strip and a second arc-shaped strip, one end of the second rectangular strip is provided at the circumferential edge of the circular patch, the other end extends into the circular patch and is connected to one end of the second arc-shaped strip.

[0016] Further, the length of the first rectangular strip and the second rectangular strip is 3.85mm, and the width g1 is 0.4mm; the width g2 of the first arc-shaped strip is 0.85mm, and the length is 11deg; the width g2 of the second arc-shaped strip is 0.85mm, and the length is 9deg.

[0017] Further, the gap between the arc-shaped horizontal arm and the slotted radiating patch unit is 0.15mm.

[0018] Further, the dielectric substrate material is Rogers / duroid 5880, the relative dielectric constant is 2.2, the loss tangent is 0.0009, the dielectric substrate and the metal ground plate have the same size, and the size of the dielectric substrate is 80mm in length and width.

[0019] Further, the width w of the horizontal arm is 2mm, the length is 84deg, A1: 42deg; the diameter of the shorting post is 2mm, R2: 1mm, the height is 3mm, the radius R1 of the circular patch is 15.4mm, and the included angle A1 between the L-shaped slot and the X axis is 43deg.

[0020] Due to the adoption of the above technical scheme, the present application has the following advantages:

[0021] 1. The present application uses a pair of grounded metal columns to generate a set of equivalent magnetic currents, which are symmetric about the center, so that a directional tilted dual-beam with high gain value can be formed.

[0022] 2、The application can change the surface current distribution of high order mode of the circular patch through the cut L-shaped slot, reshape the irregular conical beam to form a directional tilt radiation double beam; meanwhile, the introduction of the L-shaped slot can increase the current path to reduce the resonant frequency of high frequency.

[0023] 3、Compared with the traditional monopole antenna, the antenna of the application combines the low profile advantage of the microstrip antenna, the profile height is 0.024 lambda g, lambda g represents the wavelength value corresponding to the lowest frequency resonant frequency, the radiator diameter is R: 0.29 lambda g, easy to process integration, good directional radiation characteristics, the gain peak is as high as 9.55 dBi.

[0024] Other advantages, objects, and features of the application will be set forth in part in the following specification taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art from a consideration of the following specification and drawings, or can be learned from the practice of the application. The advantages and other objects of the application can be realized and attained by means of the instrumentalities and combinations pointed out in the following specification. BRIEF DESCRIPTION OF DRAWINGS

[0025] The drawings of the application are as follows.

[0026] Figure 1 is a perspective view of the four-frequency directional vehicle antenna of the application;

[0027] Figure 2 is a top view of the four-frequency directional vehicle antenna of the application;

[0028] Figure 3 is the antenna return loss characteristic curve and the corresponding frequency band antenna peak gain of the four-frequency directional vehicle antenna of the application calculated by HFSS software;

[0029] Figure 4 is the radiation pattern of the four-frequency directional vehicle antenna of the application at 2.45GHz;

[0030] Figure 5 is the radiation pattern of the four-frequency directional vehicle antenna of the application at 3.25GHz;

[0031] Figure 6 is the radiation pattern of the four-frequency directional vehicle antenna of the application at 4.45GHz;

[0032] Figure 7 is the radiation pattern of the four-frequency directional vehicle antenna of the application at 5.8GHz.

[0033] In the figure: 1, medium substrate; 2, metal ground plate; 3, slotted radiating patch unit; 4, coaxial feed structure; 5, first T-shaped monopole; 6, second T-shaped monopole; 7, L-shaped slot; L1, first L-shaped slot; L2, second L-shaped slot; L3, third L-shaped slot; L4, fourth L-shaped slot; W1, first rectangular strip; W2, second rectangular strip; S1, first arc-shaped strip; S2, second arc-shaped strip; 31, first horizontal arm; 32, second horizontal arm; P1, first shorting post; P2, second shorting post. DETAILED DESCRIPTION

[0034] The application will be further described below with reference to the drawings and examples.

[0035] In the description of the embodiments of the application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance. In the description of the embodiments of the application, it should be noted that unless otherwise specifically specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the application can be understood according to the specific circumstances.

[0036] A four-frequency-band directional vehicle-mounted antenna can be designed to have different beam characteristics according to the needs of different frequency bands, such as in V2V communication, DSRC frequency band communication needs to have omnidirectional or double-end radiation performance; WIFI and Bluetooth frequency bands need to have directional radiation performance; in base station communication application, WiMax frequency band needs to have high gain value of directional inclined double-beam radiation performance; sub-6G communication application frequency band needs to be designed as an antenna with directional radiation performance.

[0037] As shown in Figure 1 , it comprises a metal ground plate 1, a medium substrate 2, a slotted radiating patch unit 3, a coaxial feed structure 4 and a T-shaped monopole stub, and the T-shaped monopole stub is two, which are a first T-shaped monopole stub 5 and a second T-shaped monopole stub 6.

[0038] The metal floor 1 is attached to the lower surface of the dielectric substrate 2, the slotted radiating patch unit 3 is parallel to the metal floor 1 and located on the upper surface of the dielectric substrate 2, the inner conductor of the coaxial feed structure 4 is connected with the slotted radiating patch unit 3, and the outer conductor is connected with the metal floor 1. The first T-shaped monopole stub 5 and the second T-shaped monopole stub 6 are respectively symmetrically located on both sides of the slotted radiating patch unit 3.

[0039] As shown in Figure 2 The slotted radiating patch unit 3 is a circular patch, four L-shaped slots 7 are formed on the circumferential edge of the circular patch, the four L-shaped slots 7 are respectively a first L-shaped slot L1, a second L-shaped slot L2, a third L-shaped slot L3 and a fourth L-shaped slot L4, the first L-shaped slot L1 and the second L-shaped slot L2 are equal in size, the third L-shaped slot L3 and the fourth L-shaped slot L4 are equal in size, the first L-shaped slot L1 and the second L-shaped slot L2 are symmetric about the central axis X of the antenna, the third L-shaped slot L3 and the fourth L-shaped slot L4 are symmetric about the central axis X of the antenna, the first L-shaped slot L1 and the third L-shaped slot L3 are symmetric about the other central axis Y of the antenna, and the second L-shaped slot L2 and the fourth L-shaped slot L4 are symmetric about the other central axis Y of the antenna.

[0040] The first L-shaped slot L1 and the second L-shaped slot L2 each include a first rectangular strip W1 and a first arc-shaped strip S1, one end of the first rectangular strip W1 is formed at the circumferential edge of the circular patch, the other end extends into the circular patch and is connected with one end of the first arc-shaped strip S1.

[0041] The third L-shaped slot L3 and the fourth L-shaped slot L4 each include a second rectangular strip W2 and a second arc-shaped strip S2, one end of the second rectangular strip W2 is formed at the circumferential edge of the circular patch, the other end extends into the circular patch and is connected with one end of the second arc-shaped strip S2.

[0042] The T-shaped monopole stubs located on both sides of the circular patch are respectively the first T-shaped monopole stub 5 and the second T-shaped monopole stub 6, the first T-shaped monopole stub 5 includes a first horizontal arm 31 and a first short connecting column P1, one end of the first short connecting column P1 is in contact with the first horizontal arm 31, and the other end is connected with the ground; the second T-shaped monopole stub 6 includes a second horizontal arm 32 and a second short connecting column P2, one end of the second short connecting column P2 is in contact with the second horizontal arm 32, and the other end is connected with the ground.

[0043] The first horizontal arm 31 and the second horizontal arm 32 are respectively located on both sides of the circular patch and are parallel to the circumference of the circular patch.

[0044] The length of the first rectangular strip W1 and the second rectangular strip W2 is 3.85mm, and the width g1 is 0.4mm; the width g2 of the first arc-shaped strip S1 is 0.85mm, and the length is 11deg; the width g2 of the second arc-shaped strip S2 is 0.85mm, and the length is 9deg.

[0045] The gap between the first horizontal arm 31 and the second horizontal arm 32 and the slotted radiating patch unit is 0.15mm.

[0046] The material of the dielectric substrate 1 is Rogers / duroid 5880, the relative dielectric constant is 2.2, and the loss tangent is 0.0009; the dielectric substrate 1 and the metal ground plate 2 have the same size, and the size of the dielectric substrate 1 is 80mm in length and width.

[0047] The width w of the first horizontal arm and the second horizontal arm is 2mm, the length is 84deg, and A1 is 42deg; the diameter of the first shorting post P1 and the second shorting post P2 is 2mm, R2 is 1mm, the height is 3mm, the radius R1 of the circular patch is 15.4mm, and the included angle A1 of the L-shaped slot and the X-axis is 43deg.

[0048] After the initial design is completed, simulation analysis is performed using high-frequency electromagnetic simulation software HFSS, and the optimal sizes of various parameters after simulation optimization are shown in Table 1:

[0049] Table 1 Optimal size table of various parameters of the application

[0050]

[0051] According to the above parameters, the reflection coefficient, peak gain and four frequency band radiation pattern characteristic parameters of the designed small-size four-frequency directional vehicle-mounted antenna are simulated and tested using HFSS, and the analysis results are as follows:

[0052] As shown in Figure 3 , it is a small-size four-frequency directional vehicle-mounted antenna reflection coefficient |S 11 | simulation curve and peak gain curve, between 2.42-2.47GHz, 3.23-3.27GHz, 4.44-4.51GHz and 5.78-5.82GHz |S 11|<-10dB, relative bandwidths are 2%, 1.2%, 1.6% and 0.7% respectively, and four resonance points are generated at 2.45GHz, 3.25GHz, 4.45GHz and 5.8GHz, it is pointed out that for vehicle-mounted applications, such as WIFI-2.4G and DSRC (Dedicated Short Range Communication) dedicated short-range communication frequency bands are based on narrowband design, therefore the bandwidth of each frequency band of the antenna in the application belongs to the narrowband range. In addition, the coordinate axis on the right side of the figure represents the peak gain value of the antenna, corresponding to the four frequency bands, the peak gain values from low frequency to high frequency are 6.33dBi, 6.98dBi, 9.55dBi and 6.83dBi respectively.

[0053] As shown in Figures 4-7 , the vehicle-mounted antenna of the application is simulated by using electromagnetic simulation software HFSS. The antenna radiation patterns at 2.45GHz, 3.25GHz, 4.45GHz and 5.8GHz are given respectively. It can be seen that the antenna has good radiation performance at different frequencies, and has strong radiation ability in the specified direction, that is, the antenna has good directional radiation.

[0054] As shown in Figure 4 , the antenna presents axial radiation, and the maximum gain value corresponds to the angle directly above the antenna. Figure 5 In the middle, the antenna presents left and right dual directional radiation, and the maximum gain value corresponds to the angle of θ=±44°. Figure 6 In the middle, the antenna presents axial radiation, and the maximum gain value corresponds to the angle directly above the antenna. Figure 7 In the middle, the antenna presents front and back dual directional radiation, and the maximum gain value corresponds to the angle of θ=±34°.

[0055] In summary, the small size four-band directional vehicle-mounted antenna of the application has the advantages of excellent radiation characteristics, compact size, simple structure and high gain.

[0056] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the application and not to limit them, although the application has been described in detail with reference to the above examples, those skilled in the art should understand that the specific embodiments of the application can be modified or replaced, without departing from the spirit and scope of the application, any modification or equivalent replacement, which should be covered within the protection scope of the claims of the application.

Claims

1. A four-band directional vehicle-mounted antenna, comprising a metal ground plane and a dielectric substrate attached to the upper surface of the metal ground plane, characterized in that, The antenna also includes a slotted radiating patch unit, a coaxial feed structure, and two T-shaped monopole stubs; The slotted radiating patch unit is parallel to the metal floor and is disposed on the upper surface of the dielectric substrate; The coaxial feeding structure has its inner conductor connected to the slotted radiating patch unit and its outer conductor connected to the metal ground plane. Two T-shaped monopole stubs are arranged opposite each other with equal spacing on both sides of the slotted radiating patch unit to excite the equivalent magnetic current at both ends of the circular patch. The slotted radiating patch unit is a circular patch with four L-shaped slots on its circumferential edge.

2. The four-band directional vehicle-mounted antenna as described in claim 1, characterized in that, Each T-shaped monopole stub includes a shorting post and an arc-shaped horizontal arm. One end of the shorting post contacts the horizontal arm, and the other end is connected to the ground. The two arc-shaped horizontal arms are located opposite each other on both sides of the circular patch and are parallel to the circumference of the circular patch.

3. The four-band directional vehicle-mounted antenna as described in claim 1, characterized in that, The four L-shaped grooves are respectively the first L-shaped groove, the second L-shaped groove, the third L-shaped groove, and the fourth L-shaped groove; The first and second L-shaped grooves are of equal size and correspond to the two ends of one of the horizontal arms; the third and fourth L-shaped grooves are of equal size and correspond to the two ends of the other horizontal arm. The first L-shaped slot and the second L-shaped slot are symmetrical about the central axis X of the antenna, and the third L-shaped slot and the fourth L-shaped slot are symmetrical about the central axis X of the antenna; The first L-shaped slot and the third L-shaped slot are symmetrical about the other central axis Y of the antenna, and the second L-shaped slot and the fourth L-shaped slot are symmetrical about the other central axis Y of the antenna.

4. The four-band directional vehicle-mounted antenna as described in claim 3, characterized in that, The first L-shaped groove and the second L-shaped groove both include a first rectangular strip and a first arc-shaped strip. One end of the first rectangular strip is opened at the circumferential edge of the circular patch, and the other end extends into the circular patch and is connected to one end of the first arc-shaped strip. Both the third L-shaped groove and the fourth L-shaped groove include a second rectangular strip and a second arc-shaped strip. One end of the second rectangular strip is opened at the circumferential edge of the circular patch, and the other end extends into the circular patch and is connected to one end of the second arc-shaped strip.

5. The four-band directional vehicle-mounted antenna as described in claim 4, characterized in that, The length of both the first and second rectangular strips is 3.85 mm, and the width is... g 1 The width is 0.4 mm; the width of the first arc-shaped strip g 2 It measures 0.85mm and has a length of 11deg; The width of the second arc-shaped strip g 2 It measures 0.85mm and has a length of 9deg.

6. The four-band directional vehicle-mounted antenna as described in claim 2, characterized in that, The gap between the arc-shaped horizontal arm and the slotted radiating patch unit is 0.15 mm.

7. The four-band directional vehicle-mounted antenna as described in claim 1, characterized in that, The dielectric substrate material is Rogers / duroid 5880, with a relative permittivity of 2.2 and a loss tangent of 0.0009. The dielectric substrate and the metal ground plane have the same dimensions, with the length and width of the dielectric substrate both being 80 mm.

8. The four-band directional vehicle-mounted antenna as described in claim 2, characterized in that, The width of the horizontal arm w It is 2mm thick and 84deg long. A 1 :42deg; The diameter of the shorting post is 2mm. R 2 The diameter of the circular patch is 1mm, the height is 3mm, the radius R1 of the circular patch is 15.4mm, and the angle between the L-shaped groove and the X-axis is... A 1 It is 43deg.

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