CN107706507A - Dual-frequency antenna - Google Patents

Abstract

A dual-band antenna includes a first antenna portion and a second antenna portion. The dual-frequency antenna is used for feeding a first resonance signal and a second resonance signal, wherein the frequency of the second resonance signal is greater than that of the first resonance signal. The first antenna part includes: the second antenna part further comprises a first sub-radiator and a second sub-radiator. An included angle is formed between the second radiation section and the first radiation section. The lengths of the first radiation section and the second radiation section correspond to the wavelength of the second resonance signal and the wavelength of the first resonance signal respectively. The second sub-radiator is arranged between the first antenna part and the first sub-radiator. Further, the length of the second antenna portion is shorter than the length of the second radiating section.

Description

dual frequency antenna

technical field

The invention relates to a dual-frequency antenna, and in particular to a dual-frequency dipole antenna capable of improving the bandwidth of a resonance signal.

Background technique

With the rapid development of network technology, wireless communication has been closely integrated with the lives of most people. Therefore, portable electronic products with wireless communication functions have also become the mainstream of the market. In order to provide the wireless communication function, the portable electronic product needs to install an antenna through a built-in or an external way, and receive radio frequency (radiofrequency) signals from the outside through the antenna. Based on the consideration of thinness and shortness, portable electronic products must use a miniaturized antenna design to reduce the size of the antenna body as much as possible.

As wireless communication-related products are increasingly emphasizing practicality and technology, the demand for multi-band and broadband has also emerged. To this end, portable electronic products need to support multiple wireless communication standards. Incidentally, the small antennas used in portable electronic products must also be able to receive radio frequency signals in different frequency bands.

Contents of the invention

The invention relates to a dual-frequency antenna, and in particular to a dual-frequency dipole antenna capable of improving bandwidth. The dual-frequency antenna of the present invention improves the bandwidth of the resonance signal in the low frequency band through the coupling structure, and improves the bandwidth of the resonance signal in the high frequency band through the hypotenuse section.

According to one aspect of the present invention, a dual-frequency antenna is provided for feeding a first resonant signal and a second resonant signal, wherein the frequency of the second resonant signal is higher than the frequency of the first resonant signal. The dual-frequency antenna includes: a first antenna part and a second antenna part. The first antenna part further includes: a first radiating section and a second radiating section connected to each other, and a first angle is formed between the first radiating section and the second radiating section. The length of the first radiation segment corresponds to the wavelength of the second resonance signal; and the length of the second radiation segment corresponds to the wavelength of the first resonance signal. The second antenna part includes: a first sub-radiator and a second sub-radiator. The first sub-radiator includes a coupling section to extend the section. A second angle is formed between the extension section and the coupling section. The second sub-radiator is disposed between the first antenna part and the first sub-radiator, and at least a part of the second sub-radiator is parallel to the coupling section.

In order to have a better understanding of the above-mentioned and other aspects of the present invention, the preferred embodiments are specifically cited below, together with the accompanying drawings, and are described in detail as follows:

Description of drawings

Fig. 1 is a schematic diagram of a dual-band antenna conceived by the present invention.

Fig. 2 is a schematic diagram of the length configuration of the first antenna part of the dual-frequency antenna.

3A and 3B are schematic diagrams of different aspects of the first radiation section.

4A, 4B, 4C, and 4D are schematic diagrams of different aspects of the second radiation section.

Fig. 5 is a schematic diagram of the length configuration of the second antenna part of the dual-frequency antenna.

6A and 6B are schematic diagrams of different forms of the first sub-radiator.

7A and 7B are schematic diagrams of second sub-radiators in different forms.

Fig. 8 is a schematic diagram of an embodiment of a dual-band antenna conceived according to the present invention.

9A, 9B, and 9C are schematic diagrams illustrating the details of the dual-frequency antenna shown in FIG. 8 .

10A and 10B are schematic diagrams of current paths when the dual-frequency antenna of the present invention feeds control signals.

【Symbol Description】

Substrate 10 Dual-frequency dipole antenna 1, 2

First feed point 15a, 25a Second feed point 15b, 25b

The first antenna part 11, 21

The first radiating section 111, 311, 312, 211

Second radiating sections 112, 411, 412, 413, 414, 212

Second antenna part 12, 22

The first sub-radiators 121, 621, 622, 221

Coupling section 121a, 6211, 6221, 221a

Second extension section 121b, 221b

Second sub-radiators 122, 721, 722, 222

Distance d1, d2, d3, d4, d5 Length L1 of the first antenna part

Length L11 of the first radiating section Length L12 of the second radiating section

Angle α1, α2, α3, α4, β1, β2

Hypotenuse sections 3111, 3121, 211a

Straight section 3122, 211b First extension section 4111, 4131

Small segments 412a, 412b, 412c, 412c, 412d, 412e, 4141a, 4141b, 4141c, 4141d, 4141e, 6222a, 6222b, 6222c, 6222d

Length L2 of the vertical section 4132, 4142 second antenna portion

The length L21 of the first sub-radiator The length L21a of the parallel section

Length L21b of the second extension section

The length L22 of the second sub-radiator Long side sections 721a, 722a

Short side section 722b coaxial cable 27

RF transceiver module 29

Width w1, w2, w3, w4, w5, w6, w7

First first current CP11 First second current CP12

Second first current CP21 Second second current CP22

detailed description

The application of multiple frequency bands has become a necessary consideration when designing antennas. If the wireless signal transmission module of the portable electronic product integrates the 802.11b and 802.11a specifications of the Wireless Local Area Network (Wireless LAN) standard, its antenna structure or circuit must be designed to be applicable to two different operating frequencies of 2.4GHz and 5GHz. Such an antenna capable of receiving wireless communication signals in different frequency bands is called a dual band antenna (Dual Band Antenna).

When designing a dual-frequency antenna, the appearance of the dual-frequency antenna must meet the conditions of resonance before it can be used to feed the resonance signal. The frequency of the first resonant signal (first resonant frequency f1) is 2.4 GHz and the frequency of the second resonant signal (second resonant frequency f2) is 5 GHz as an example to illustrate how to design parameters related to the dual-band antenna in the present invention. However, in actual application, according to the frequency of different resonance signals, how to adjust and replace the parameters such as the length and angle of the designed dual-frequency antenna can be obtained through conversion.

When the length of the radiator of the dual-frequency antenna is, for example, an integer multiple of 1/4 wavelength of the resonance signal, the resonance condition can be achieved, and the resonance condition will make the radiator antenna and the feeding part match each other. Therefore, the present application aims at the application of the first resonant signal with a frequency of 2.4GHz and the second resonant signal with a frequency of 5GHz, according to a quarter of the first resonant wavelength λ1 (1/4*λ1=12.5cm/4= 31.25 mm (millimeter, mm for short), and a quarter of the second resonance wavelength λ2 (1/4*λ2=6cm/4=15mm) to design the length parameters related to the dual-frequency antenna. In addition, the antenna length can also be designed to be related to 1/1*λ1, 1/1*λ2, 1/2*λ1 or 1/2*λ2.

Please refer to FIG. 1 , which is a schematic diagram of a dual-frequency dipole antenna contemplated by the present invention. The dual-band dipole antenna 1 disposed on the substrate 10 includes: a first feeding point 15 a , a second feeding point 15 b , a first antenna part 11 and a second antenna part 12 . In the following description, the radiator of the first antenna part 11 is represented by the bottom of the grid in the vertical direction, and the radiator of the second antenna part 12 is represented by the grid bottom of the grid line, and different regions are divided by bold dotted lines. part. It should be noted that the segments demarcated by bold bold dotted lines are still connected to each other.

For the sake of illustration, it is assumed here that the substrate 10 has a rectangular appearance, its long side is parallel to the x direction (the first direction), and its short side is parallel to the y direction (the second direction). The substrate 10 can be a single-sided printed circuit board made of glass fiber, a double-layer or multi-layer printed circuit board, and the like. The radiator of the dual-frequency dipole antenna 1 is made of metal conductive material. If the substrate 10 is a double-layer or multi-layer printed circuit board, no metal structure can be formed or arranged on the other side corresponding to the position of the dual-frequency dipole antenna 1, so as to prevent the dual-frequency dipole antenna 1 from feeding a resonance signal. , interfered by his side.

As shown in FIG. 1 , the radiator of the present invention is based on a strip-shaped design. Therefore, the length of the sides of the radiator is approximately equal to the length of its centerline. Considering the convenience of wiring, the width of the radiator is roughly equal, for example, the width can be designed to be one-thousandth of the first resonance wavelength λ1, 12.5cm/1000=0.125mm.

According to an embodiment of the present invention, the first antenna part 11 includes only one radiator; the second antenna part 12 includes two first sub-radiator 121 and second sub-radiator 122 parallel to each other and separated by a small distance. Wherein, the position of the second sub-radiator 122 is between the first antenna part 11 and the first sub-radiator 121 , and the length of the second sub-radiator 122 is shorter than that of the first antenna part 11 and the first sub-radiator 121 . In addition, the distance d1 between the second sub-radiator 122 and the first antenna part 11 must be greater than or equal to 1 mm.

The first antenna part 11 can be divided into two parts, the first radiating section 111 and the second radiating section 112 . Wherein, there is an angle α1 between the second radiating section 112 and the first radiating section 111 . In the second antenna part 12, the first sub-radiator 121 can be further divided into a coupling section 121a and a second extending section 121b. Wherein, there is an included angle β1 between the coupling section 121a and the second extension section 121b. According to the idea of the present invention, the coupling section 121a is arranged parallel to the second sub-radiator 122 , and the distance between the coupling section 121a and the second sub-radiator 122 is quite close to form a coupling effect.

In the dual-frequency dipole antenna shown in FIG. 1 , the length, appearance, and location of each radiator can be further changed and adjusted. The following describes several ways of possible matching when designing the appearance of the first antenna part 11 and the second antenna part 12 . In actual application, the appearance of the first antenna part and the second antenna part can be selected and designed according to factors such as the space of the substrate. The various appearances of the radiators in the accompanying drawings can also be used in any combination and combination.

Please refer to FIG. 2 , which is a schematic diagram of the length configuration of the first antenna part of the dual-frequency dipole antenna. The first antenna part 11 uses the first radiation section 111 to cooperate with the second resonance signal. Therefore, the length L11 of the first radiation section 111 is designed to be a quarter of the second resonance wavelength λ2, L11=1/4*λ2. The first antenna part 11 uses the second radiation section 112 to cooperate with the first resonance signal. Therefore, the length L12 of the second radiating section 112 is designed to be a quarter of the first resonance wavelength λ1, L12=1/4*λ1.

Continuing the foregoing description, it can be known that if the first resonant frequency is 2.4 GHz and the second resonant frequency is 5 GHz, the length L11 of the first radiating section is about 15 mm, and the length L12 of the second radiating section is about 31.25 mm. The length L1 of the first antenna part 11 is equal to the sum of the lengths of the first radiating section 111 and the second radiating section 112 , ie, L1=L11+L12=1/4*(λ1+λ2). For example: 15+31.25=46.25mm. In addition, because the second resonance frequency is greater than twice the first resonance frequency, the wavelength of the first resonance signal is greater than twice the wavelength of the first resonance signal. Therefore, in Figure 2, 1/4*λ2<1/2*1/4*λ1.

Hereinafter, possible appearance changes of the first radiating section 111 will be described by using FIGS. 3A and 3B ; possible appearance changes of the second radiating section 111 will be described by using FIGS. 4A , 4B, 4C and 4D. Wherein, various appearance changes of the first radiating section 111 and the second radiating section 111 can be matched with each other, and no special limitation is required.

The appearance of the first radiating section 111 can be further divided into two categories, the first category is the situation including only the hypotenuse section (as shown in Figure 3A); the second category is the situation including the hypotenuse section and the straight section (as shown in Figure 3A). 3B).

Please refer to FIG. 3A , which is a schematic diagram of the first radiating section including only the hypotenuse section. Since the first radiating section 311 in FIG. 3A only includes the hypotenuse section 3111 , the length L11 a of the hypotenuse section 3111 is equal to the length L11 of the first radiating section 311 . That is, L11a=L11=1/4*λ2. In addition, the angle α2 between the hypotenuse section 3111 and the vertical direction must meet the restriction of 0°<α2<90°.

Please refer to FIG. 3B , which is a schematic diagram of the first radiating section including both a hypotenuse section and a straight section. If the first radiating section 312 includes both the hypotenuse section 3121 and the straight section 3122 , the sum of the length L11 a of the hypotenuse section 3121 and the length L11 b of the straight section 3122 is equal to the length L11 of the first radiating section 311 . That is, L11a+L11b=L11=1/4*λ2. Wherein, the length L11a of the hypotenuse section 3121 may be less than, equal to, or greater than the length L11b of the straight section 3122 .

The included angle α4 between the hypotenuse section 3121 and the vertical direction is greater than 0°, and the included angle α3 between the hypotenuse section 3121 and the straight section 312 is greater than or equal to 90°. The hypotenuse section 3121 can be shifted counterclockwise with the upper endpoint as the center, thereby changing the size of the included angle α4. Similarly, the straight side section 3122 can use the connection point with the hypotenuse section 3121 as an end point, and can be shifted counterclockwise or clockwise, thereby changing the size of the included angle α3. When the included angle α3 is 180°, it corresponds to the situation that only includes the hypotenuse section. In actual application, the offset range between the hypotenuse section 3121 and the straight section 3122 can be based on the principle that the straight section 3122 does not touch the second radiation section.

The appearance of the second radiating section 112 can be further divided into two categories. The first category includes only the first extension section (as shown in Figures 4A and 4B); the second category includes both the first extension section and the first extension section. The situation of the vertical section (as shown in Fig. 4C, 4D). In any case, the length L12 of the second radiating section 112 is 1/4*λ1 (for example: 31.25 mm).

In the case where the second radiating section only includes the first extension section, it can be further divided into two types according to the appearance of the first extension section. One is that the first extension section itself does not have any corners and is simply a long strip. Shaped appearance (as shown in Figure 4A); the second is that the first extension section itself contains a plurality of small sections, and the corners are formed between each small section, and the overall appearance of the first extension section is concave-convex (as shown in Figure 4B shown). In Figures 4A and 4B, the length of the second radiating section is equal to the length L12a of the first extending section. Therefore, the length L12a of the first extension section is a quarter of the first resonance wavelength λ1, L12a=1/4*λ1.

Please refer to FIG. 4A , which is a schematic diagram of the second radiating section only including the first extension section, and the first extension section does not have any corners. The second radiating section 411 only includes the first extension section 4111 , and the first extension section 4111 is in a horizontal direction. Therefore, the included angle α5 between the first extension section 4111 and the vertical direction is, for example, a right angle. That is, α5=90°.

Please refer to FIG. 4B , which is a schematic diagram assuming that the second radiating section only includes the first extension section, and the first extension section includes a knuckle. The second radiating section 412 includes a first extending section, and the first extending section can be further divided into a plurality of small sections 4121a, 4121b, 4121c, 4121d, 4121e with shorter lengths. These small segments 4121a, 4121b, 4121c, 4121d, 4121e form a knuckle with each other of about 90°.

The method of meandering the first extension section to form a knuckle can reduce the area occupied by the dual-band antenna on the substrate. In actual application, whether the first extension section has a knuckle, the length of each small section separated by the knuckle, and the number of knuckles do not need to be limited.

In order to prevent the first radiating section from being too close to the second radiating section, in addition to the first extending section, the second radiating section can also use a vertical section. Wherein, the length of the first extension section is longer than that of the vertical section. Figures 4C and 4D show the situation where the second radiating section includes both the first extension section and the vertical section, wherein Figure 4C corresponds to the situation where the first extension section does not have a knuckle, and Figure 4D corresponds to the situation where the first extension section has a knuckle situation.

Please refer to FIG. 4C , which is a schematic diagram showing that the second radiating section includes both the first extending section and the vertical section, and the first extending section has no corner. The second radiating section 413 includes a first extending section 4131 and a vertical section 4132 . The sum (L12a+L12b) of the length L12a of the first extension section 4131 and the length L12b of the vertical section 4132 is equivalent to the length L12 of the second radiating section. That is, L12a+L12b=L12=1/4*λ1.

Please refer to FIG. 4D , which is a schematic diagram assuming that the second radiating section includes both the first extending section and the vertical section, and the first extending section has a knuckle. The second radiating section 414 includes both a first extending section and a vertical section 4142 , wherein the first extending section is composed of a plurality of shorter small sections 4141a, 4141b, 4141c, 4141d, 4141e. Although FIG. 4D depicts five small segments, the number of knuckles actually included in the first extension segment, the length of the small segments, etc., are not limited.

Please refer to FIG. 5 , which is a schematic diagram of the length configuration of the second antenna part of the dual-frequency dipole antenna. The second antenna part 12 includes a first sub-radiator 121 and a second sub-radiator 122 . The length L22 of the second sub-radiator 122 is shorter than the length L21 of the first sub-radiator 121 . Due to the coupling formed between the coupling section 121 a of the first sub-radiator 121 and the second sub-radiator 122 , the total length of the second antenna part 12 can be made shorter than 1/4*λ1. That is, L21+L22=L2<1/4*λ1.

The first sub-radiator 121 may further include a coupling section 121a and a second extension section 121b. Therefore, the length 21 of the first sub-radiator 121 is equal to the sum of the length L21a of the coupling section 121a and the length L21b of the second extension section 121b, ie, L21=(L21a+L21b).

The following describes possible changes in the appearance of the first sub-radiator 121 and the second sub-radiator 122 . Wherein, the appearance change of the first sub-radiator 121 will be described in FIGS. 6A and 6B . The appearance change of the second sub-radiator 122 will be described in FIGS. 7A and 7B .

According to the appearance of the second extension section, the appearance of the first sub-radiator 121 can be further divided into two types. One is that the second extension section has an elongated appearance without any corners; the other is that the second extension section has at least one corner, and its overall appearance is concave-convex. 6A and 6B are divided into cases where the second extension section of the first sub-radiator does not have a corner and has a corner.

Please refer to FIG. 6A , which is a schematic diagram of the second extension section without a corner. The first sub-radiator 621 includes a coupling section 6211 and a second extension section 6212 . Wherein the coupling section 6211 is parallel to the vertical direction. The length of the coupling section 6211 is L21a, and the length of the second extension section 6212 is L21b. Since the length L21 of the first sub-radiator 121 must satisfy: 1/4*λ2<L21<1/4*λ1, the sum of the lengths of the coupling section 6211 and the second extension section 6212 must meet 1/4*λ2<L21a +L21b=Limitation of L21<1/4*λ1. In addition, the angle β1 between the coupling section 6211 and the second extension section 6212 is between 90° and 180°. That is, (90≦β1≦180).

Please refer to FIG. 6B , which is a schematic diagram of the second extension section having a knuckle. The first sub-radiator 621 includes a coupling section 6221 and a second extension section. In this figure, the second extension section includes a plurality of small sections 6221a, 6221b, 6221c, 6221d, 6221e of shorter length. Whether the second extension section includes a knuckle, the length of each small section, and the number of knuckles do not need to be limited.

As shown in Figures 3B, 4B, and 6B, when the first extension section and/or the second extension section have knuckles, the number of knuckles does not need to be limited, and the length of each small section does not need to be limited and needs to be equal. . In one or more small segments included in the first extension section and/or the second extension section, if it is combined with other radiators (such as the first radiation section in Figure 3B, 4B, and the coupling section in Figure 6 ) start numbering, then the small segments belonging to the odd numbers are parallel to each other, and the small segments belonging to the odd numbers are perpendicular to the small segments belonging to the even numbers.

The appearance of the second sub-radiator can be further divided into two categories, the first category is the situation that only includes the long side section (as shown in Figure 7A, I-shaped); the second category is the situation that includes the long side section and the short side section Situation (as shown in Figure 7B, inverted L shape).

Please refer to FIG. 7A , which is a schematic diagram of the second sub-radiator only including the long side section. When the second sub-radiator 721 only includes the long side section 721a, the second feeding point (not shown) will be set at the top of the long side section 721a. In FIG. 7A , the shortest distance between the second sub-radiator 721 and the first antenna part (not shown) corresponds to the distance from the right side of the long side section 721 a to the first antenna part L1 .

Please refer to FIG. 7B , which is a schematic diagram of the second sub-radiator including both the long-side section and the short-side section. As shown in FIG. 7 , the second sub-radiator includes both a long side section 722 a and a short side section 722 b. The length L22a of the long side section 722a is shorter than the length L22b of the short side section 722b, and the angle β2 between them is a right angle (β2=90°). When the second sub-radiator 722 is L-shaped, the second feeding point (not shown) is disposed at the far right of the short side section 722b. At this time, the shortest distance between the second sub-radiator 722 and the first antenna part (not shown) corresponds to the distance from the rightmost edge of the short side section 722b to the first antenna part L1.

Please refer to FIG. 8 , which is a schematic diagram of an embodiment of a dual-frequency dipole antenna conceived according to the present invention. The dual-frequency dipole antenna 2 is disposed on the substrate 20. According to the control of the radio frequency transceiver module (transceiver) 29, the coaxial cable 27 and the dual-frequency dipole antenna 20 are fed into the first resonance signal and the second resonance signal through the feeding point. The first feeding point 25a is used for feeding ground signals, and the second feeding point 25b is used for feeding electromagnetic signals.

When the resonance signal is transmitted through the first feeding point 25a and the second feeding point 25b, the current generates a waveguide (waveguide) through the transmission line to form an electromagnetic wave to radiate out, thereby achieving the transmission of the electromagnetic signal; when the resonance signal passes through the first feeding point 25a When receiving with the second feeding point 25b, the radiation of electromagnetic energy is received through the antenna to form electric energy of radio frequency, thereby achieving the transmission of electromagnetic signals.

The second sub-radiator 222 and the coupling section 221a of the first sub-radiator 221 jointly form a coupling structure, and the length L22 of the second sub-radiator 222 is quite close to the length of the coupling section 221a of the first sub-radiator 221 . When the second sub-radiator 222 has an I-shaped shape, the length of the second sub-radiator 222 is less than or equal to the length of the coupling section of the first sub-radiator. When the second sub-radiator 222 is in an inverted L shape, the length of the long side section is less than or equal to the length of the coupling section 221 a of the first sub-radiator 221 . At this time, the length of the short side section will affect the comparison result between the length of the second sub-radiator 222 and the length of the coupling section 221 a of the first sub-radiator 221 .

Please refer to FIG. 9A , which is a schematic diagram of the first antenna part in the dual-frequency dipole antenna. Through the use of the hypotenuse section 211a, the dual-frequency dipole antenna can have a larger bandwidth range when feeding a high-frequency resonance signal. After confirmation by simulation, for the application of the second resonance frequency of 5 GHz, the bandwidth of the resonance signal in the high frequency band is increased from 1150 MHz to 1870 MHz. That is, the dual-frequency dipole antenna of the present application can improve the bandwidth of the resonant signal in the high frequency band by 62.6%. Since the feed-in point is disposed on the beveled section 211a, in order to avoid short circuit when soldering the feed-in point, the width w2 of the beveled section 211a is wider than the width w1 of the straight section 211b (w2>w1).

Please refer to FIG. 9B , the second antenna part of the dual-frequency dipole antenna. The dual-frequency dipole antenna of the present invention uses a coupling structure in the second antenna part, which can improve the bandwidth of the resonance signal fed into the low frequency band. Simulation results show that for the application of the first resonance frequency of 2.4GHz, the bandwidth of the first resonance signal can be increased from 100MHz to 120MHz, an increase of 20%.

In this figure, the distance d2 between the second sub-radiator 222 and the coupling section 221b is less than 0.8mm (0<d2<0.8). The length of the short side section 222b of the second sub-radiator 222 is between 0-3.2mm, and the length of the long side section 222a is between 7.25mm and 8.25mm. Accordingly, the ratio of the length of the long side section 222 a to the length of the short side section 222 b in this embodiment is between 2.578125 and infinity (∞).

Considering the convenience of wiring, in Figures 9A and 9B, in addition to the width w2 of the hypotenuse section 211a, the width w1 of the straight section 212b, the width w3 of the first extension section; the width w6 of the short section 222b ; and the width w5 of the long side section 222a and the width w7 of the second extension section 221b may be equal to each other.

Alternatively, the width w5 of the long-side section 222a is second only to the width w2 of the hypotenuse section 211a, but the width w6 of the short-side section 222b, the width w1 of the straight-side section 212b in the first antenna part, the width w1 of the first extension section The width w3 is wider than the width w4 of the coupling section 221 a of the first sub-radiator 221 and the width w7 of the second extension section 221 b.

Please refer to FIG. 9C , which is a schematic diagram further illustrating the relative positions of the dual-frequency dipole antennas according to the embodiment of the present invention. The distance d3 is the shortest distance between the long side section and the hypotenuse section. The distance d4 is the longest distance between the side closer to the second antenna portion 13 and the side of the short side section in the vertical section. The distance d5 is the shortest distance between the hypotenuse section and the first extension section. Based on the consideration of setting the feeding point, in FIG. 9C , the spacing d3 and the spacing d4 are at least 1 mm. Furthermore, the distance d5 must be greater than 0 mm. In actual application, regardless of whether the second sub-radiator 222 has an inverted L shape or an I-shape, the minimum distance between the second sub-radiator 222 and the first radiating section 211 mainly depends on the welding space required for the feeding point . That is, it is used to avoid a short circuit between the feeding point 25a and the feeding point 25b.

With the different frequency bands used, the current path in the dual-frequency dipole antenna also changes. FIGS. 10A and 10B respectively represent the current paths when the dual-frequency dipole antenna is applied to resonance signals in the low frequency band and high frequency band.

Please refer to FIG. 10A , which is a schematic diagram of a dual-frequency dipole antenna used to feed the first resonance signal. The first first current CP11 flows through the second radiation section of the first antenna part 21 , and the first second current CP12 flows through the first sub-radiator 221 and the second sub-radiator 222 of the second antenna part 22 . Depending on whether the RF transceiver module 29 is set for transmission or reception, the flow directions of the first first current CP11 and the first second current CP12 will change accordingly. Regardless of the direction in which the current flows, the intensity of the current will be inversely proportional to the distance between the feed points. Therefore, the first first current CP11 has a stronger current intensity near the first feeding point 25 a; and, the first second current CP12 has a stronger current intensity near the second feeding point 25 b.

Please refer to FIG. 10B , which is a schematic diagram of a dual-frequency dipole antenna used to feed the second resonance signal. The second first current CP21 flows through the first radiation section of the first antenna part 21 . At the same time, the second second current CP22 flows through a part of the first sub-radiator 221 , the second sub-radiator 222 . As the radio frequency transceiver module 29 is set to transmit or receive, the flow directions of the second first current CP21 and the second second current CP22 will change accordingly. Regardless of the direction in which the current flows, the intensity of the current will be inversely proportional to the distance between the feed points. Therefore, the current intensity of the second first current CP21 near the first feeding point 25 a is relatively strong, and the current intensity of the second second current CP22 near the second feeding point 25 b is relatively strong.

10A and 10B, it can be seen that the current path corresponding to the first resonance signal with a lower frequency (the flow path of the first first current CP11 and the first second current CP12) is smaller than that of the second resonance signal with a higher frequency. The corresponding current paths (the flow paths of the second first current CP21 and the second second current CP22 ) are long.

According to the idea of the present invention, the second resonance frequency is about twice or more than the first resonance frequency. For example, the dual-frequency dipole antenna of the present invention can be applied to the situation where the first resonant frequency is 800/900 MHz and the second resonant frequency is 1800 MHz. Alternatively, the dual-frequency dipole antenna of the present invention can be applied to the situation where the first resonant frequency is 2400-2500 MHz, and the second resonant frequency is 5150-5850 MHz.

In order to cope with the thin, light and small features of the portable electronic device, the dual-band dipole antenna can be built into a corner of the system circuit board of the portable electronic device. Alternatively, the substrate used for disposing the antenna can be another printed circuit board with a relatively small size, which is independently disposed on the inner wall of the housing of the electronic device, and used together with a coaxial cable or a button-type RF connector. The dual-frequency dipole antenna of the present invention can be easily adjusted and corrected to meet the operating frequency band required by the system according to product requirements, and is applicable to many wireless communication devices.

In summary, although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the art to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims (13)

1. a kind of dual-band antenna, the frequency for the resonance signal of feed-in first and the second resonance signal, wherein second resonance signal Rate is higher than the frequency of first resonance signal, and the dual-band antenna includes：

First antenna portion, comprising：

First radiant section, the wherein length of first radiant section correspond to the wavelength of second resonance signal；And

Second radiant section, it is connected with first radiant section, and the first angle, wherein second spoke is formed with first radiant section The length for penetrating section corresponds to the wavelength of first resonance signal；And

Second antenna part, comprising：

First sub- radiant body, comprising：

Couple section；And

Extension of section, with the second angle of the intersegmental formation in the coupled zone；And

Second sub- radiant body, it is arranged between the first antenna portion and the first sub- radiant body, and the second sub- radiant body is at least A part is parallel to the coupling section.

2. dual-band antenna as claimed in claim 1, the wherein first sub- radiant body are grown compared with the second sub- radiant body, and this second Distance between sub- radiant body and the first sub- radiant body is less than the distance between the second sub- radiant body and the first antenna portion.

3. the length of dual-band antenna as claimed in claim 1, the wherein length of the first sub- radiant body and the second sub- radiant body The summation of degree is shorter than the length of second radiant section.

4. dual-band antenna as claimed in claim 1, the wherein frequency of second resonance signal are more than or equal to first resonance Twice of the frequency of signal, wherein

The length of first radiant section is a quarter of the wavelength of first resonance signal；And

The length of second radiant section is a quarter of the wavelength of second resonance signal.

5. dual-band antenna as claimed in claim 1, wherein second radiant section are parallel to first direction, and the coupling section is put down Row is vertical with the second direction in second direction, the wherein first direction.

6. dual-band antenna as claimed in claim 5, wherein first angle is acute angle, and second angle is right angle or is blunt Angle.

7. dual-band antenna as claimed in claim 5, wherein first radiant section include：

Hypotenuse section, with intersegmental formation first angle of the second radiation；And

The 3rd angle is formed between straight flange section, with the hypotenuse section.

8. dual-band antenna as claimed in claim 7, the wherein width of the hypotenuse section are more than the width of the straight flange section, and should 3rd angle is obtuse angle.

9. dual-band antenna as claimed in claim 1, wherein,

When the second sub- radiant body is I type shapes, the second sub- radiant body be shorter in length than or the length equal to the coupling section Degree；Or

When the second sub- radiant body is inverted L shape shape, the second sub- radiant body includes short side section and long side section, and the length Border area section is shorter than or the length equal to the coupling section.

10. dual-band antenna as claimed in claim 9, wherein the long side section are parallel to the coupling section, and the short side section Beeline between the first antenna portion is shorter than or equal to the long side section and the beeline in the first antenna portion.

11. dual-band antenna as claimed in claim 1, wherein,

When the dual-band antenna is used for feed-in first resonance signal, the one the first electric currents flow through second radiant section, and first Second electric current flows through the second sub- radiant body and the first sub- radiant body；And

When the dual-band antenna is used for feed-in second resonance signal, the two the first electric currents flow through first radiant section, and second Second electric current flows through the second sub- radiant body and the partial first sub- radiant body.

12. dual-band antenna as claimed in claim 11, wherein also including：

First load point, is arranged at first radiant section and second radiation is intersegmental, wherein the one the first electric currents with this second First electric current flows through first load point；And

Second load point, one end of the second sub- radiant body is arranged at, wherein the one the second electric currents and the two the second electric currents Flow through second load point.

13. dual-band antenna as claimed in claim 1, the wherein extension of section include an at least away minor segment, wherein at this at least In one away minor segment, first community section adjacent to each other and the intersegmental formation knuckle of second community.