CN101471484B - Multi-frequency antenna - Google Patents

Abstract

The present invention relates to a multi-frequency antenna, comprising: a ground plane, a supporting substrate and a radiating metal part; the ground plane has a first short-circuit point and a second short-circuit point; the radiating metal part is attached to the surface of the supporting substrate and comprises: a first radiating metal line, a radiating metal sheet, a second radiating metal line and a parasitic radiating metal arm; one end of the first radiating metal line is a feeding end of the antenna, and the other end is electrically connected to the first short-circuit point of the ground plane, and the radiating metal sheet is electrically connected to a section of the first radiating metal line; the second radiating metal line is surrounded by the first radiating metal line, and one end of the second radiating metal line is electrically connected to the first radiating metal line; one end of the parasitic radiating metal arm is electrically connected to the second short-circuit point of the ground plane.

Description

A multi-frequency antenna

technical field

The invention relates to a mobile phone antenna, in particular to a multi-frequency antenna suitable for being built into a mobile phone.

Background technique

With the rapid development of wireless communication, antennas play a more important role in wireless communication products. Especially under the trend of light, thin, short, and small, the height of the antenna will affect the value of a product, and most of these wireless communication products use flat-panel antennas or exposed monopole antennas as the main design types. The thickness of the known dual-frequency mobile phone panel antenna needs about 7-10mm, such as TW patent announcement No. 490,884 "dual-frequency inverted F-shaped panel antenna and its radiating metal sheet", which discloses a The ground, and the example of the built-in mobile phone antenna used in the mobile communication system GSM (Global System for Moblie Communications) and DCS (Digital Cellular System) dual-band operation, makes the overall thickness of the mobile phone obviously exceed 10mm. If we apply the above-mentioned known antenna technology to a thin mobile phone (thickness of the mobile phone is about 10 mm or less), we will face the problem that the thickness of the antenna is too large, and cannot really meet the requirements of thin mobile phones.

In order to solve this problem in this field, monopole antennas are often used for design. Since the exposed monopole antenna protruding from the ground plane is less affected by the ground plane, the thickness of the antenna can be reduced to achieve a thin mobile phone antenna. Applications.

However, whether it is a flat-panel antenna or a monopole antenna, due to the limited design space used in mobile phones, the GMS frequency band usually only covers the GSM850 operating frequency band; however, mobile phone applications are now moving towards multi-frequency development. Most of the panel antennas or monopole antennas can only meet the dual-band requirements of GSM/DCS in a limited space, and it is difficult to design antennas that meet the requirements of multi-band applications.

Contents of the invention

In response to the increasing demand for multi-frequency antennas, in order to provide mobile phone antennas that meet multi-frequency applications, we propose a multi-frequency antenna that can be formed on a support substrate. The metal wires electrically connected at the position cooperate to realize the five-frequency operation of GSM850/900 (820-960MHz)/DCS (1710-1880MHz)/PCS (1850-1990)/UMTS (1920-2170MHz). The antenna of the present invention is a half-wavelength resonant mode of a loop antenna in the low frequency part. This resonant mode can cover the operation requirements of GSM850/900, while the high frequency part is a broadband operation synthesized by two resonant modes. The specific resonant mechanism Will be introduced later. The bandwidth of the low-frequency operating frequency band of the antenna of the present invention is about 140MHz (820～960MHz), which can cover the operation of GSM850/900, and the bandwidth of the high-frequency operating frequency band is about 460MHz (1700～2170), and can also cover DCS/PCS/ The operation of UMTS meets the application requirements of the actual mobile phone system.

As mentioned above, the purpose of the present invention is to provide a multi-frequency mobile phone antenna, which can not only meet the requirements of the GSM850/900/DCS/PCS/UMTS operating frequency band, but also has a simple structure and a clear operating mechanism. It has industrial application value.

The antenna of the present invention includes: a ground plane, a supporting base and a radiating metal part. The ground plane has a first short-circuit point and a second short-circuit point; the shape of the support base is roughly hexahedron, and its material can be plastic or ceramics or Styrofoam or microwave substrate material; and the above-mentioned radiating metal part is attached to the support base surface, and the radiating metal part includes: a first radiating metal wire, a radiating metal sheet, a second radiating metal wire and a parasitic radiating metal arm. The shape of the first radiating metal wire is roughly ring-shaped, and has a first end point and a second end point, wherein the first end point is the feed-in end of the antenna, used to connect to the radio frequency signal line of the mobile phone system module, and the The second terminal point is electrically connected to the first short-circuit point of the ground plane; the radiating metal sheet is electrically connected to a section of the first radiating metal wire; the shape of the second radiating metal wire is roughly an inverted L shape, Surrounded by the first radiating metal wire, and one end point of the second radiating metal wire is electrically connected to the first radiating metal wire; the shape of the parasitic radiating metal arm is also roughly an inverted L shape, and has been bent once, and the parasitic radiating metal arm One terminal of the arm is electrically connected to the second short circuit point of the ground plane.

If the antenna of the present invention is applied to a mobile phone system, the ground plane is the system ground plane of the internal circuit of the mobile phone, on which system modules and circuit elements can be arranged.

In the present invention, the first radiating metal wire is used to resonate the half-wavelength and full-wavelength resonant modes (operating at 1000MHz and 1800MHz respectively), and then cooperate with the radiating metal sheet and the parasitic radiating metal arm to extend the first radiating metal wire. The effective resonant path makes the resonance frequency of the first resonant mode (half-wavelength mode) of the first radiating metal line drop, and also cooperates with the third resonant mode provided by the second radiating metal line, and the full-wavelength mode of the first radiating metal line mode synthesis - wideband operation.

The first resonant mode of the antenna of the present invention provides an operating bandwidth of 140MHz, which is sufficient to cover the operational requirements of GSM850/900; the second and third resonant modes are combined to form a broadband operation, providing an operating bandwidth of about 460MHz, and can cover Operational requirements of DCS/PCS/UMTS.

The return loss of the antenna provided by the present invention in the required frequency band (GSM850/900: 824-960MHz, DCS/PCS/UMTS: 1710-2170MHz) is higher than 6dB, which meets the requirements of practical applications. At the same time, the antenna design provided by the present invention has a simple structure and a clear operating mechanism, and it is easy to achieve multi-frequency requirements through design; and the radiating metal part of the antenna can be adhered to the surface of the supporting substrate, and this antenna design method using surface adhesion technology can be used. The convenience of integrating the whole antenna with the system circuit board is improved, so the antenna of the present invention is an antenna with application value.

The above and other objects and advantages of the present invention will be more apparent through the detailed description of the embodiments of the present invention with reference to the accompanying drawings.

Description of drawings

Fig. 1 is a structural diagram of an antenna according to a first embodiment of the present invention.

Fig. 2 is a structural diagram of an antenna according to a second embodiment of the present invention.

Fig. 3 is the return loss test result of the antenna according to the first embodiment of the present invention.

Fig. 4 is a radiation pattern diagram of the first resonance mode (880 MHz) of the antenna according to the first embodiment of the present invention.

Fig. 5 is a radiation pattern diagram of the second resonance mode (1840 MHz) of the antenna according to the first embodiment of the present invention.

Fig. 6 is a radiation pattern diagram of the third resonance mode (2110 MHz) of the antenna according to the first embodiment of the present invention.

Fig. 7 is a low frequency operation band gain diagram of the antenna according to the first embodiment of the present invention.

Fig. 8 is a gain diagram of the high-frequency operating band of the antenna according to the first embodiment of the present invention.

Fig. 9 is a structural diagram of an antenna according to another embodiment of the present invention.

Detailed ways

Fig. 1 is a configuration diagram of a multi-frequency antenna 1 according to a first embodiment of the present invention. The multi-frequency antenna 1 includes: a ground plane 11 , a supporting base 12 and a radiating metal part 13 . The above-mentioned ground plane 11 has a first short-circuit point 111 and a second short-circuit point 112; the shape of the support base 12 is roughly hexahedron, and its material can be plastic or ceramic or Styrofoam or microwave substrate material; the above-mentioned radiating metal part 13 is attached to On the surface of the support base 12 , the radiating metal part 13 includes: a first radiating metal wire 14 , a radiating metal sheet 15 , a second radiating metal wire 16 and a parasitic radiating metal arm 17 . The shape of the first radiating metal wire 14 is roughly ring-shaped, and has a first end point 141 and a second end point 142, wherein the first end point 141 is the feed-in end of the antenna, which is used to connect the radio frequency signal line of the mobile phone system module 10, and the second terminal 142 is electrically connected to the first short-circuit point 111 of the ground plane 11; the radiating metal sheet 15 is electrically connected to a section of the first radiating metal line 14; the second radiating metal line 16 The shape is roughly an inverted L shape, surrounded by the first radiating metal wire 14, and the terminal 161 of the second radiating metal wire 16 is electrically connected to the first radiating metal wire 14; and the shape of the parasitic radiating metal arm 17 is also roughly It is in an inverted L shape and is bent once, and its end point 171 is electrically connected to the second short-circuit point 112 of the ground plane 11 .

If the above-mentioned antenna of the present invention is applied to a mobile phone system, the ground plane 11 is the system ground plane of the internal circuit of the mobile phone, on which system modules and circuit components can be arranged. The return loss test results of this embodiment are shown in FIG. 3 .

Fig. 2 is a structural diagram of a multi-frequency antenna 2 according to a second embodiment of the present invention. The structure of the multi-frequency antenna 2 is substantially the same as that of the multi-frequency antenna 1 according to the first embodiment, and the multi-frequency antenna 2 according to the second embodiment also includes: a ground plane 11, a supporting base 12 and a radiating metal part 13, only the radiating metal The structure of the part 13 is slightly different from the multi-frequency antenna 1 of the first embodiment, the radiation metal part 13 of the multi-frequency antenna 2 does not have a parasitic radiation metal arm, and the rest is the same as the multi-frequency antenna 1 of the first embodiment.

FIG. 3 is an experimental test result of the return loss of the multi-frequency antenna 1 according to the first embodiment of the present invention. In this experiment, the following dimensions are selected for testing: the size of the ground plane 11 is 40×75mm ² , the area occupied by the antenna is 40×10×5mm ³ , and the antenna is composed of a supporting base (polystyrene material) 12 and attached to the supporting base 12 The radiation metal portion 13 on the surface is formed. The radiating metal part 13 is the main body of the antenna, mainly including the first radiating metal wire 14 , the radiating metal sheet 15 , the second radiating metal wire 16 and the parasitic radiating metal arm 17 . The first radiating metal wire 14 is roughly formed into a ring, the line width is about 0.5mm, and the total length is about 100mm, and its two ends are respectively the feed-in end 141 and the short-circuit end 142 of the antenna. The signal line 10, and the short-circuit end 142 is connected to the first short-circuit point 111 of the ground plane 11; the radiating metal sheet 15 has a size of 40×15mm ² , is bent into an inverted L shape with a height of 5mm, and is electrically connected to the A section of the first radiating metal line 14; the width of the second radiating metal line 16 is 5mm, and the length is about 20mm, its shape is roughly an inverted L shape, and is surrounded by the first radiating metal line 14, and the second radiating metal line 16 The end point 161 of the two radiating metal wires 16 is electrically connected to the position of the first radiating metal wire 14 close to the feeding end 141, and the distance between the end point 161 and the feeding end 141 of the antenna is less than 20 mm; the parasitic radiating metal arm 17 is a width of A metal arm with a length of 1 mm is about 11 mm and is bent once. Its end point 171 is electrically connected to the second short-circuit point 112 of the ground plane 11 . Actual operation and testing are carried out according to this design dimension. Since the first radiating metal wire 14 is a ring structure, it can generate a half-wavelength and a full-wavelength resonant mode, and the center frequencies of these two resonant modes are located at 1000MHz and 1800MHz respectively; Cooperating with the radiating metal sheet 15 and the parasitic radiating metal arm 17 (the functions of both are to prolong the equivalent resonance path of the first radiating metal wire), the first resonant mode of the first radiating metal wire 14 ( The resonant frequency of the half-wavelength mode) drops, and this resonant mode provides an operating bandwidth of 140MHz, which is sufficient to cover the operational requirements of GSM850/900; while the second radiating metal line 16 provides an additional resonant mode at 2100MHz, which can be compared with the first radiating metal The second resonant mode (full wavelength mode) of line 14 is combined to provide a broadband operating bandwidth of about 460 MHz, and can cover the operating requirements of DCS/PCS/UMTS. The antenna of the present invention has a return loss higher than 6dB in the frequency band required by mobile phone applications (GSM850/900: 824-960MHz, DCS/PCS/UMTS: 1710-2170MHz), which meets the requirements of practical applications.

FIG. 4 is a radiation pattern at 880 MHz of the multi-frequency antenna 1 according to the first embodiment of the present invention. As shown in the figure, the radiation pattern of the half-wavelength mode resonated by the first radiating metal wire combined with the radiating metal sheet and the parasitic radiating metal arm is the same as the radiation when the frequency of the traditional monopole antenna or panel antenna resonates The patterns are similar in that they are donut-shaped radiation patterns.

FIG. 5 is a radiation pattern at 1840 MHz of the multi-frequency antenna 1 according to the first embodiment of the present invention. As shown in the figure, the radiation pattern of the full-wavelength mode resonated by the first radiating metal wire in cooperation with the radiating metal sheet and the parasitic radiating metal arm is affected by the ground plane length (75mm) of the antenna of the present invention, which is A radiation pattern is different from the butterfly-shaped radiation pattern when the traditional mobile phone antenna resonates at 1800MHz. There is no concave point on the x-y plane, and it has a nearly omnidirectional radiation pattern on this plane.

Fig. 6 is a radiation pattern at 2110 MHz of the multi-frequency antenna 1 according to the first embodiment of the present invention. As shown in the figure, the radiation pattern of the third resonant mode resonated by the second radiation metal wire is also because the ground plane length of the antenna of the present invention is 75mm, so this radiation pattern and the traditional mobile phone antenna resonate at 2000MHz The butterfly-shaped radiation pattern of the above is different, there is no concave point in the x-y plane, and it also has a nearly omnidirectional radiation pattern on this plane. Combining the test results of the radiation pattern of the high-frequency resonance mode in Fig. 5 and Fig. 6, it can be seen that the radiation pattern of the antenna of the present invention has the advantages of reducing the sag in the radiation pattern compared with the butterfly-shaped pattern of the traditional mobile phone antenna operating at high frequencies. point of merit.

Fig. 7 is the antenna gain diagram in the low frequency operating frequency band according to the multi-frequency antenna 1 of the first embodiment of the present invention, the antenna gain in the GSM850/900 frequency band is about -2.7～-0.6dBi, and Fig. 8 is the high frequency (DCS/PCS/UMTS) Antenna gain diagram in the operating frequency band, the gain in the DCS/PCS/UMTS frequency band is about -1.7 ~ 3.5dBi, which generally meet the needs of practical applications. In addition, the antenna of the present invention is suitable for mobile communication products with different ground plane sizes, and when the ground plane size is 40×100mm ² , the obtained antenna gain can be higher. In addition, as far as the multi-frequency antenna 2 of the second embodiment is concerned, if its radiating metal part 13 is slightly different from the multi-frequency antenna 1 of the first embodiment, if the ground plane size of ⁴⁰ ×100mm2 is used, it can also obtain At least three resonant modes provide at least five-frequency operation to achieve the same effect as the multi-frequency antenna 1 of the first embodiment.

Fig. 9 is a structural diagram of an antenna 9 according to another embodiment of the present invention. The overall structure of the antenna 9 according to this embodiment is substantially the same as that of the multi-frequency antenna 1 of the first embodiment, but the radiation metal part of the antenna 9 of this embodiment is the same as the radiation metal part of the multi-frequency antenna 1 of the first embodiment. Slightly different in structural details. The radiating metal portion of the antenna 9 according to this embodiment includes: a first radiating metal wire 14, a radiating metal sheet 15, a second radiating metal wire 16 and a parasitic radiating metal arm 17; wherein the first radiating metal wire 14 and the radiating metal sheet 15 The shape and configuration are similar to the multi-frequency antenna 1 of the first embodiment, except that the shape of the second radiating metal wire 96 is a straight line, and the parasitic radiating metal arm 97 is also a straight line (without bending), but its configuration Still similar to the configuration of the multi-frequency antenna 1 in the first embodiment. The above-mentioned another embodiment can also smoothly resonate at least three resonance modes, provide at least five-frequency operation, and achieve the same effect as the multi-frequency antenna 1 of the first embodiment.

Based on the above description, the antenna of the present invention has a simple structure and a clear operating mechanism. The radiating metal part of the antenna can be surface-bonded on the surface of the supporting substrate, and this antenna design concept using the surface-mounting process can improve the antenna as a whole and the system. Because of the convenience of circuit board integration, the antenna of the present invention has high industrial application value.

The implementation manners described above are only preferred embodiments of the present invention, and the scope of the present invention cannot be limited thereby.

Claims (8)

1. multifrequency antenna comprises:

Ground plane has a short dot at least;

Support base; And

Radiation metal portion is attached to this support base surface, and comprises:

First radiation metal wires is roughly annular, has first end points and second end points, this first end points feed side that is antenna wherein, and this second end points then is electrically connected to the short dot of this ground plane;

Radiation sheet metal is electrically connected to one of this first radiation metal wires section; With

Second radiation metal wires is centered on by first radiation metal wires, and an end points of second radiation metal wires is connected electrically on first radiation metal wires;

Wherein, This ground plane has first short dot and second short dot; And second end points of this first radiation metal wires is connected electrically to first short dot of ground plane; And radiation metal portion has the parasitic radiation metal arm in addition, and an end points of this parasitic radiation metal arm is connected electrically to second short dot of ground plane.

2. multifrequency antenna as claimed in claim 1 is characterized in that, this ground plane is the system ground of mobile phone internal circuit.

3. multifrequency antenna as claimed in claim 1 is characterized in that, first end points of this first radiation metal wires is the feed side of antenna, and is connected to the rf signal line of cell phone system module.

4. multifrequency antenna as claimed in claim 1 is characterized in that, the material of this support base is from the group of being made up of plastic cement, Poly Foam, pottery and microwave base plate material, to choose.

5. multifrequency antenna as claimed in claim 1 is characterized in that the shape of this support base is roughly hexahedron.

6. multifrequency antenna as claimed in claim 1 is characterized in that the shape of this second radiation metal wires is roughly L shaped.

7. multifrequency antenna as claimed in claim 1 is characterized in that, this second radiation metal wires be shaped as linear.

8. multifrequency antenna as claimed in claim 1 is characterized in that the shape of this parasitic radiation metal arm is roughly L shaped.

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