CN104134857B - A kind of eight frequency range planographic antenna for mobile phone - Google Patents

Abstract

An eight-band planar printed mobile phone antenna, including a dielectric board, a main floor printed on one side of the dielectric board and a parasitic ground branch, and an excitation unit and a signal feed line printed on the other side of the dielectric board; the main board and the parasitic ground branch are directly connected , the gap between the two is L-shaped; the end of the parasitic branch is engraved with an L-shaped open circuit groove; the excitation unit includes the first branch, the second branch, and the third branch, and these three branches are directly connected to the signal feed-in line The mobile phone antenna is a planar structure, which can use planar printing technology to expand the bandwidth by using multiple resonance points, and each resonance point can be easily adjusted to form two wider bandwidths in the low frequency band and high frequency band, thus covering the current 4G communication. All cell phone bands. Compared with the prior art, the planar printed mobile phone antenna of the present invention has the advantages of two-dimensional structure, broadband and multi-band and easy adjustment, and is suitable for various small mobile terminals represented by mobile phones.

Description

An eight-band planar printed mobile phone antenna

technical field

The invention relates to a mobile terminal antenna, in particular to an eight-band planar printed mobile phone antenna.

Background technique

With the rapid development of mobile communication technology, mobile phones have become one of the most popular consumer electronics products in the world. The function of the mobile phone has also developed from a single voice service to an integrated service based on network, digital, multimedia video and so on. Considering that the communication protocols and allocated frequency bands adopted in different parts of the world are not the same, in order to realize global roaming, mobile terminal antennas need to be able to support multi-protocol and multi-band coverage. On the basis of 2G and 3G, 4G, which is initially put into commercial use, divides more frequency bands to achieve higher data transmission. The frequency bands covered by 4G are LTE700(698-784MHz), GSM850(824-894MHz), GSM900(880-960MHz), DCS(1710-1880MHz), PCS(1850-1990MHz), UMTS(1920-2170MHz), LTE2300(2300MHz) -2400MHz), LTE2500 (2500-2690MHz). Therefore, mobile terminal antennas supporting 4G generally need to cover the low frequency band of 698-960MHz and the high frequency band of 1710-2690MHz.

The performance of the antenna needs enough space for guarantee. In order to cover the above two frequency bands, the typical design method is to use three-dimensional structures, such as PIFA antennas and folded monopole antennas. This type of antenna has more degrees of freedom and can be adjusted, and generally can meet the frequency band coverage requirements. However, the three-dimensional structure is not conducive to processing and high integration, and cannot adapt to the current trend of thinner and thinner mobile phones. Planar printed mobile phone antennas are attracting more and more attention. In terms of design, planar printed antennas usually use two branches with similar lengths. The fundamental modes of the two branches are combined to cover the low frequency band of 698-960MHz; the high-order modes of the two branches are combined to cover the high frequency band of 1710-2690MHz. This design method can easily adjust the fundamental modes of the two branches, but it is difficult to adjust the high-order modes independently, which increases the complexity of debugging. Therefore, it is of great significance to design a planar printed mobile phone antenna that meets the requirements of the 4G frequency band and can be adjusted independently in the low frequency band and high frequency band.

Contents of the invention

In order to overcome the above-mentioned shortcoming of prior art, the object of the present invention is to provide a kind of planar printed mobile phone antenna that can cover all frequency bands of 4G; Each mode within a frequency band can be adjusted relatively independently.

In order to realize above-mentioned function, the technical scheme that the present invention adopts is:

An eight-band planar printed mobile phone antenna, comprising a dielectric board 6, a main floor 1 printed on one side of the dielectric board 6, a parasitic ground branch 3, and a signal feed-in line 2 and an excitation unit 4 printed on the other side of the dielectric board 6, wherein:

The main floor 1 is connected to the parasitic ground branch 3;

An L-shaped open circuit groove 5 is opened on the parasitic ground branch 3;

The excitation unit 4 includes a first branch 4a, a second branch 4b and a third branch 4c, wherein the first branch 4a is L-shaped, the second branch 4b and the third branch 4c are straight, and the The second branch 4b and the third branch 4c are parallel to each other;

The signal feed-in line 2 is directly connected to the first branch 4a, the second branch 4b, and the third branch 4c.

There is an L-shaped gap between the main floor 1 and the parasitic ground branch 3 , and the positions of the signal feed-in line 2 and the excitation unit 4 correspond to the gap.

The first branch 4a is formed by vertically connecting one end of the first arm to one end of the second arm, the other end of the second arm is connected to one end of the second branch 4b, and one end of the signal feed-in line 2 is vertically connected to the first branch. On the two arms, the projection of the other end is located on the main floor 1, and one end of the third branch 4c is vertically connected to the signal feed-in line 2, and the third branch 4c and the second branch 4b are located on the same side of the signal feed-in line 2.

The line widths of the signal feed-in line 2 and the first branch 4a, the second branch 4b, and the third branch 4c of the excitation unit 4 are all equal.

The L-shaped open circuit slot 5 is located at the end of the parasitic ground branch 3, the width of the metal parts on both sides of the long arm of the open circuit slot is equal, the width of the long arm of the open circuit slot is equal to the width of the short arm, and the direction of the opening of the slot is the same as that of the first part of the excitation unit 4. The first arms of one branch 4a are parallel.

The second branch 4b and the third branch 4c of the excitation unit 4 are located in the L-shaped gap.

The characteristic impedance of the part of the microstrip line projected on the main floor 1 by the signal feed-in line 2 is 50 ohms.

Holes are opened on the main floor 1 , and a 50-ohm coaxial line is used to directly feed power. The inner conductor of the coaxial line is connected to the excitation unit 4 , and the outer conductor is connected to the main floor 1 .

The 0.25λ mode resonance of the parasitic ground branch 3 is near 720MHz, and the 0.75λ mode resonance is near 1750MHz; the 0.25λ mode resonance of the second branch 4b of the excitation unit 4 is near 920MHz, and the 0.25λ mode resonance of the third branch 4c is The resonance is around 2900MHz; the 0.25λ mode resonance of the L-shaped open groove 5 is around 2450MHz.

Compared with prior art, the beneficial effect of the present invention is:

(1) Covers eight frequency bands including GSM700, GSM850, GSM900, DCS, PCS, UMTS, LTE2300, and LTE2500 with a planar structure to meet the needs of 4G communication.

(2) The planar size of the antenna is 15mm×60mm, which occupies a small size, and the cost can be reduced by a planar printing process.

(3) The structure of the antenna is simple, the debugging is convenient, the working mode is clear, and the modes in each frequency band can be adjusted relatively freely.

Description of drawings

Fig. 1 is a schematic plan view of an eight-band planar printed mobile phone antenna provided by the present invention.

Fig. 2 is a top view of the implementation example after the antenna in Fig. 1 is installed, and the unit is millimeter (mm).

Fig. 3 is a bottom view of the implementation example after the antenna in Fig. 1 is installed, and the unit is millimeter (mm).

Fig. 4 is a side view of an implementation example of the antenna in Fig. 1 after installation, and the unit is millimeter (mm).

Fig. 5 is a reflection coefficient diagram of an example simulation after the antenna in Fig. 1 is installed.

FIG. 6 is a radiation efficiency diagram of an example simulation implemented after the antenna in FIG. 1 is installed.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a schematic structural view of the eight-band planar printed mobile phone antenna of the present invention. As shown in Fig. 1, the eight-band planar printed mobile phone antenna of the present invention includes: a dielectric board 6, a main floor 1, a signal feed-in line 2, and a parasitic ground branch 3. Excitation unit 4. The main floor 1 and the parasitic branch 3 are printed on one side of the dielectric board 6 , and the signal feed-in line 2 and the excitation unit 4 are printed on the other side of the dielectric board. The main floor 1 is used to simulate the circuit board of a mobile phone. An L-shaped open circuit groove 5 is formed on the parasitic ground branch 3 . The excitation unit 4 includes a first branch 4a, a second branch 4b, and a third branch 4c, and these three branches are directly connected to the signal feed-in line 2 . The characteristic impedance of the microstrip part of the signal feed-in line 2 located on the main floor 1 is 50 ohms.

Technical scheme of the present invention is realized like this:

The first is to achieve low frequency band (698-960MHz) coverage. The parasitic ground branch 3 resonates at 720 MHz, and the effective electrical length of the parasitic ground branch 3 at this frequency point is about 0.25λ, so it works in the fundamental mode. The third branch 4c of the excitation unit 4 resonates at 920MHz, and the effective electrical length of the third branch 4c at this frequency point is about 0.25λ, so it works in the fundamental mode. These two fundamental modes can form a wider bandwidth due to the interaction of coupling and so on, so as to realize the coverage of low frequency band. Since the resonant frequencies of the two fundamental modes are mainly determined by their respective effective electrical lengths, the two resonant modes in the low frequency band can be adjusted by adjusting the respective lengths relatively independently.

The second is to realize the coverage of the high frequency band (1710-2690MHz). The parasitic ground branch 3 and the third branch 4c of the excitation unit 4 generate the fundamental mode in the low frequency band, and at the same time generate the third mode in the high frequency band. Considering that the bandwidth provided by these two tertiary modes is not enough to cover the entire high frequency, and the adjustment of these two tertiary modes is affected by the adjustment of the fundamental mode and cannot be adjusted independently, a new resonant unit is introduced to expand the bandwidth and adjust the high frequency mode in the frequency band. Specifically, an L-shaped open slot 5 is engraved on the parasitic ground branch 3, and the open slot generates resonance at 2450 MHz. The effective electrical length of the open slot at this frequency point is about 0.25λ, so it works in the fundamental mode. The second branch 4b of the excitation unit 4 resonates at 2750MHz, and the effective electrical length of this branch at this frequency point is about 0.25λ, so it works in the fundamental mode. On the other hand, the third-order mode of the parasitic ground branch 3 is pulled down to 1750MHz by the two newly introduced resonant units, and the third-order mode of the third branch 4c of the excitation unit 4 is pulled up to more than 3000MHz. Four modes, such as the third mode of the parasitic ground branch 3, the fundamental mode of the L-shaped open-circuit groove 5, the fundamental mode of the second branch 4b of the excitation unit 4, and the third mode of the third branch 4c of the excitation unit 4, are due to interactions such as coupling, A wider bandwidth can be formed to achieve high-frequency coverage. Moreover, the fundamental mode of the L-shaped open-circuit groove 5 and the fundamental mode of the second branch 4b of the excitation unit 4 can be adjusted independently, and have almost no influence on the two fundamental modes in the low frequency band. The first branch of the excitation unit 4 is used to adjust the mutual coupling of the four resonant modes in the high frequency band, so as to optimize the impedance matching in the high frequency band.

In order to verify the effectiveness of the scheme of the present invention, specific examples are given below for illustration.

Figures 2 to 4 show the dimensional drawings of the implementation examples at different angles such as top view, bottom view and side view, and the units of all dimensions in each figure are millimeters (mm). In this implementation example, an FR4 dielectric substrate with a relative permittivity of 4.4, a loss tangent of 0.02, and a thickness of 0.8 mm is selected, and the plane size of the substrate is 120*60 mm ² . The plane size of the main floor is 105*60*60mm ² . The overall antenna has a planar structure, is located on one side of the main floor, and occupies a planar size of 15*60mm ² . The characteristic impedance of the microstrip line part of the signal feed line 2 located on the main floor 1 is 50 ohms. In actual implementation, it can be properly extended to the RF feed-in part of the circuit, or a hole can be opened on the main floor, and a 50-ohm coaxial line can be used to directly feed power. The inner conductor of the coaxial line is connected to the excitation unit, and the outer conductor is connected to the main floor.

Figure 5 shows the simulation reflection coefficient results of mobile phone antennas manufactured with the dimensions shown in Figure 2, Figure 3 and Figure 4 above. It can be seen from the figure that the planar printed antenna has two resonance points in the low frequency band, forming a -6dB bandwidth of 688-1045MHz, covering the three frequency bands of LTE700, GSM850 and GSM900. The planar printed antenna has four resonance points in the high frequency band, forming a -6dB bandwidth from 1685MHz to over 3000MHz, covering the five frequency bands of DCS, PCS, UMTS, LTE2300 and LTE2500.

Figure 6 shows the radiation efficiency results of the mobile phone antenna simulation with the dimensions shown in Figure 2, Figure 3 and Figure 4 above. The radiation efficiency of the mobile phone antenna in the low frequency band is about 80%, and the radiation efficiency in the high frequency band fluctuates between 70%-90%.

It can be seen from the above-mentioned technical scheme that the mobile phone antenna of the present invention realizes the coverage of eight mobile phone frequency bands in the plane space of 60 × 15mm ² , and each mode can be adjusted conveniently to meet the multi-frequency requirements of the mobile communication system for mobile terminals. Design requirements for planar printed antennas.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (8)

1. eight frequency range planographic antenna for mobile phone, comprise dielectric-slab (6), are printed in dielectric-slab (6)The main floor (1) of one side and autoeciously branch (3) and be printed in the signal of dielectric-slab (6) another sideFeed-in line (2) and exciting unit (4), wherein:

Described main floor (1) is connected with branch (3) autoeciously;

In described branch autoeciously (3), have L shaped open circuit groove (5);

Described exciting unit (4) comprises the first branch (4a), the second branch (4b) and the 3rd branch (4c),Wherein said the first branch (4a) is L shaped, and described the second branch (4b) and the 3rd branch (4c) areVertical bar shaped, and described the second branch (4b) and the 3rd branch (4c) are parallel to each other;

Described signal feed-in line (2) and the first branch (4a), the second branch (4b), the 3rd branch (4c)All directly be connected;

It is characterized in that, described main floor (1) and have L shaped space between branch (3) autoeciously,Yu Gai space, the position correspondence of described signal feed-in line (2) and exciting unit (4).

2. eight frequency range planographic antenna for mobile phone according to claim 1, is characterized in that, described inThe first branch (4a) is by one end of the first arm and vertical the connecting and composing in one end of the second arm, described the second armThe other end connect one end of the second branch (4b), described in signal feed-in line (2) one end is vertically connected onOn the second arm, it is upper that the projection of the other end is positioned at main floor (1), and one end of the 3rd branch (4c) vertically connectsBe connected on signal feed-in line (2) upper, the 3rd branch (4c) and the second branch (4b) are positioned at signal feed-in line(2) homonymy.

3. eight frequency range planographic antenna for mobile phone according to claim 1 and 2, is characterized in that,First branch (4a) of described signal feed-in line (2) and exciting unit (4), the second branch (4b),The live width of the 3rd branch (4c) all equates.

4. eight frequency range planographic antenna for mobile phone according to claim 2, is characterized in that, described inL shaped open circuit groove (5) is positioned at the end of branch (3) autoeciously, the metal part of open circuit flute length arm both sidesWidth equate, open circuit flute length arm equates with the width of galianconism, and the direction of channel opening and exciting unit (4)The first arm of the first branch (4a) parallel.

5. according to eight frequency range planographic antenna for mobile phone described in claim 1 or 2 or 4, its feature existsIn, second branch (4b) of described exciting unit (4) and the 3rd branch (4c) are positioned at described L shapedIn space.

6. eight frequency range planographic antenna for mobile phone according to claim 1, is characterized in that, described inThe microstrip line Partial Feature impedance of signal feed-in line (2) projection above main floor (1) is 50 ohm.

7. eight frequency range planographic antenna for mobile phone according to claim 6, is characterized in that, in instituteState the upper perforate in main floor (1), with the coaxial line direct feed of 50 ohm, the inner wire of coaxial line is with sharpEncourage unit (4) and be connected, outer conductor is connected with main floor (1).

8. eight frequency range planographic antenna for mobile phone according to claim 1, is characterized in that, described in0.25 λ pattern resonance of branch (3) is near 720MHz autoeciously, and 0.75 λ pattern resonance is at 1750MHzNear; 0.25 λ pattern resonance of second branch (4b) of described exciting unit (4) is attached at 920MHzClosely, 0.25 λ pattern resonance of the 3rd branch (4c) is near 2900MHz; Described L shaped open circuit groove (5)0.25 λ pattern resonance near 2450MHz.