CN1988252B - Printed folding antenna - Google Patents

Abstract

A printed folding antenna, comprising a circuit board including two conductive layers and a conducting element, a ground plane on one conductive layer, and a first radiator and a second radiator on the other conductive layer body, the first radiator is used to determine the communication frequency band, and includes a first section, a second section and a third section connected in sequence, and gradually widens from the first section to the third section, the The first section extends outward from the edge of the projected area of the ground plane, and its end close to the projected area of the ground plane is connected to a circuit on the circuit board, and the end of the third section away from the second section is close to the In the projection area of the ground plane, the second radiator is used to adjust the input impedance of the antenna, and one end thereof is connected to the first section, and the other end is connected to the ground plane through the conduction element. The present invention can make the surface current distribution of the first radiator uniform, and can achieve the effects of improving radiation gain, thinning and convenient production.

Description

Printed Folded Antenna

【Technical field】

The present invention relates to an antenna, in particular to a foldable antenna that can increase the radiated energy at the end of the antenna.

Referring to FIG. 1 and FIG. 2 , US Patent No. 6054955 discloses a folded monopole antenna (Folded Monopole Antenna) 7 . The folded monopole antenna 7 is printed on two printed circuit boards (Printed Circuit Board). The two circuit boards are a first circuit board 91 and a second circuit board 92 respectively. The first circuit board 91 is placed horizontally and has a slit 911 at the center of the top surface. The second circuit board 92 is inserted into the slit 911 of the first circuit board 91 , and the first and second circuit boards 91 , 92 are perpendicular to each other to form an inverted T-shaped structure.

The folded monopole antenna 7 includes a ground plane 71 , a first radiator 72 , a second radiator 73 and a connecting body 74 .

The ground plane 71 is located on the top surface of the first circuit board 91 .

The first radiator 72 is located on the second circuit board 92 and includes a first segment 721 and a second segment 722 . The first segment 721 vertically extends upward from a place close to the ground plane 71 . The second section 722 extends horizontally from an end of the first section 721 away from the ground plane 71 . Both the first segment 721 and the second segment 722 are rectangular.

The second radiator 73 is located on the second circuit board 92 and includes a third segment 731 and a fourth segment 732 . The third section 731 extends horizontally from two ends of the first section 721 and extends in the same direction as the second section 722 . The fourth section 732 vertically extends downward from an end of the third section 731 away from the first section 721 to the ground plane 71 . Both the third segment 731 and the fourth segment 732 are rectangular.

The second radiator 73 is used to adjust the input impedance (Input Impedance) of the folded monopole antenna 7 .

The connecting body 74 is located on the second circuit board 92 and extends horizontally from an end of the third segment 731 away from the second segment 722 , and extends in the same direction as the second segment 722 . The connection body 74 is welded to the ground plane 71 , so that the second radiator 73 is electrically connected to the ground plane 71 .

During manufacture, the ground plane 71 is manufactured together with the first circuit board 91 , and the first radiator 72 , the second radiator 73 and the connecting body 74 are manufactured together with the second circuit board 92 . Then the first and second circuit boards 91, 92 are assembled and soldered.

In use, the folded monopole antenna 7 is electrically connected to a circuit (not shown) through a wire 8 . The wire 8 includes a first conductor 81 and a second conductor 82 . The first conductor 81 is electrically connected to the junction of the first radiator 72 and the second radiator 73 , and the second conductor 82 is electrically connected to the ground plane 71 .

According to the simulation, it can be seen that the surface current (Surface Current) at the end of the first radiator 72 of the known folded monopole antenna 7 is less, so that the surface current distribution of the first radiator 72 is uneven, resulting in the known folded monopole antenna 7. The radiation gain of the monopole antenna 7 is smaller than ideal.

Furthermore, since the known folded monopole antenna 7 is printed on the two mutually perpendicular circuit boards 91, 92, and the first radiator 72 is arranged on the upright second circuit board 92, the The height of the folded monopole antenna 7 is limited by the communication frequency band, which is not conducive to thinning the product. And during manufacture, the steps of assembling and welding cannot be omitted, and during use, the wire 8 must be added to be electrically connected with the circuit (not shown), causing inconvenience in production.

【Content of invention】

Therefore, the object of the present invention is to provide a printed folded antenna, the radiator of which is bent so that its end is close to its ground plane, so that the surface current distribution of the first radiating body is uniform, and the radiator and the ground plane are located On the same circuit board, the effects of improving radiation gain, thinning and convenient production can be achieved.

In order to achieve the above purpose, the printed folded antenna of the present invention is suitable for connecting with a circuit, and includes a circuit board, a ground plane, a first radiator and a second radiator.

The circuit board includes two surfaces respectively located on the circuit board and a conduction component which can connect the two surfaces. The circuit is on this board.

The ground plane is located on a surface of the circuit board.

The first radiator is located on the other surface of the circuit board, and is used to determine the communication frequency band, and includes a first segment, a second segment and a third segment connected in sequence, and goes from the first segment to the The third segment gradually widens. The first section extends outward from the edge of the projection area of the ground plane, and one end of the first section close to the projection area of the ground plane is connected to the circuit, and the other end is connected to one end of the second section. One end of the third section is connected to the other end of the second section, and the other end of the third section is close to the projected area of the ground plane.

The second radiator is located on the same surface of the circuit board as the first radiator, and is used to adjust the input impedance of the printed folded antenna, and one end thereof is connected to the first segment of the first radiator, and the other end The conducting element of the circuit board is connected to the ground plane.

The printed folded antenna is characterized in that: the length of the first radiator is close to 1/4 wavelength of the communication frequency band.

The printed folded antenna is characterized in that: the first section extends outward from the edge of the projection area of the ground plane, and the second section bends and extends from the end of the first section away from the projection area of the ground plane, And the third section bends and extends from the end of the second section away from the first section to the projected area of the ground plane.

The printed folded antenna is characterized in that: the second section of the first radiator is substantially perpendicular to the first section, and the third section is substantially perpendicular to the second section.

The printed folded antenna is characterized in that the first section and the second section of the first radiator are both rectangular.

The printed folded antenna is characterized in that: the third section of the first radiator is rectangular, circular, trapezoidal, L-shaped, or trapezoidal with an acute angle truncated.

The printed folded antenna is characterized in that: the width of the second section of the first radiator is not smaller than the width of the first section, and the width of the third section is larger than the width of the second section.

The printed folded antenna is characterized in that: the second radiator includes a fourth section and a fifth section, and the fourth section extends outwards from between the two ends of the first section of the first radiator, And the extending direction thereof is substantially the same as that of the second section of the first radiator, and the fifth section bends and extends from an end of the fourth section far away from the first section, and is electrically connected to the ground plane.

The printed folded antenna is characterized in that: the fourth section of the second radiator is substantially perpendicular to the first section of the first radiator, and the fifth section of the second radiator is substantially perpendicular to the first section of the first radiator. Four vertical sections.

The printed folded antenna is characterized in that: the fourth section and the fifth section of the second radiator are rectangular.

In summary, the printed folded antenna of the present invention includes a circuit board including two surfaces and a conducting element, a ground plane located on one surface of the circuit board, and a first ground plane located on the other surface of the circuit board. Radiator and a second radiator. The first radiator is used to determine the communication frequency band, and includes a first segment, a second segment and a third segment connected in sequence, and gradually widens from the first segment to the third segment. The first section extends outward from the edge of the projection area of the ground plane, and an end close to the projection area of the ground plane is connected to a circuit on the circuit board. An end of the third segment away from the second segment is close to the projected area of the ground plane. The second radiator is used to adjust the input impedance of the antenna, and one end thereof is connected to the first section, and the other end thereof is connected to the ground plane through the conduction component. The printed folded antenna of the present invention bends the first radiator so that its end is close to the ground plane, so that the surface current distribution of the first radiator is uniform, and the first and second radiators are located at the same ground plane. On the circuit board, the effects of improving radiation gain, thinning and convenient production can be achieved.

【Description of drawings】

Below in conjunction with accompanying drawing and embodiment the present invention is described in detail:

FIG. 1 is a perspective view illustrating a conventional folded monopole antenna;

Fig. 2 is a side view illustrating the situation in which the folded monopole antenna is electrically connected to a wire;

Figure 3 is a plan view illustrating a preferred embodiment of the printed folded antenna of the present invention;

Fig. 4 is a schematic diagram illustrating various changes of a third section of the preferred embodiment;

Fig. 5 is a radiation field diagram, illustrating the preferred embodiment with and without the situation of the third section;

Figure 6 is a return loss diagram of the preferred example.

【Detailed ways】

Referring to Fig. 3, the preferred embodiment of the printed folded antenna of the present invention is suitable for connecting with a circuit (not shown), and includes a circuit board 1, a ground plane 2, a first radiator 3 and a second radiator Body 4.

The circuit board 1 includes two surfaces 11 respectively located on the circuit board 1 and a conductive component 12 for connecting the two surfaces 11 . In this embodiment, the circuit board 1 further includes a through hole 13 connecting the two surfaces 11 , and the conduction element 12 is realized by filling the through hole 13 with metal.

The ground plane 2 is located on a surface 11 of the circuit board 1 . The first radiator 3 , the second radiator 4 and the circuit (not shown) are located on the other surface 11 of the circuit board 1 .

The first radiator 3 includes a first segment 31 , a second segment 32 and a third segment 33 . The first section 31 extends vertically outward from the edge of the projected area of the ground plane 2 , and its end close to the projected area of the ground plane is connected to the circuit (not shown) through a transmission line 6 . The second section 32 vertically extends from an end of the first section 31 away from the projected area of the ground plane 2 . The third section 33 vertically extends from an end of the second section 32 away from the first section 31 to a projection area of the ground plane 2 . The first segment 31 , the second segment 32 and the third segment 33 are all rectangular. The width of the second segment 32 is not smaller than the width of the first segment 31 , and the width of the third segment 33 is larger than the width of the second segment 32 .

It should be noted that the first segment 31 may not be perpendicular to the edge of the projected area of the ground plane 2, the second segment 32 may not be perpendicular to the first segment 31, and the third segment 33 may not be perpendicular to the second segment 33. Segment 32 is vertical. The first section 31 and the second section 33 can be arc-shaped or zigzag-shaped. 4A, 4B, 4C, 4D, the third section 33 can be circular, trapezoidal, L-shaped or trapezoidal with an acute angle truncated (other parts are omitted in FIGS. 4A, 4B, 4C, and 4D for convenience of description).

Referring to Fig. 3, the length of the first radiator 3 is close to the 1/4 wavelength of the communication frequency band, and can be deduced by the following formula:

$\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; \&cong;</span>\frac{\mathrm{<span\; class="notranslate">\; c</span>}}{\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; f</span>}}$

c=3×108m/s

Wherein, c is the speed of light, f is the carrier frequency, and 1 is the length of the first radiator 3 .

The second radiator 4 includes a fourth segment 41 and a fifth segment 42 . The fourth segment 41 vertically extends from two ends of the first segment 31 , and extends in the same direction as the second segment 32 . The fifth section 42 vertically extends from an end of the fourth section 41 away from the first section 31 to a projected area of the ground plane 2 , and is electrically connected to the ground plane 2 via the conducting element 12 of the circuit board 1 . Both the fourth segment 41 and the fifth segment 42 are rectangular. It should be noted that the fourth segment 41 may not be perpendicular to the first segment 31 of the first radiator 3 , and the fifth segment 42 may not be perpendicular to the fourth segment 41 . The second radiator 4 is not limited to two stages.

The second radiator 4 is used to adjust the input impedance of the printed folded antenna.

When this embodiment is applied to the wireless network communication frequency band of 2.4-2.5 GHz and the circuit board 1 is a microwave substrate, the total length of the first radiator 3 is 21.5 mm, and the length 11 of the first section is the same as that of the first section. The ratio of the length 12 of the second section is about 0.33-0.38, and the ratio of the length 12 of the second section to the length 13 of the third section is about 9.1-9.6. In this case, the measurement results of the return loss (Retum Loss) of the printed folded antenna are shown in Figure 6. It can be seen from the figure that in the communication frequency band of 2.4-2.5 GHz, it has good impedance matching.

Referring to FIG. 3 , in addition to being different from the configuration of the conventional folded monopole antenna in this embodiment, the third segment 33 is added more than conventional ones. The third section 33 is the last section of the first radiator 3 and is bent close to the ground plane 2 to make the surface current distribution of the first radiator 3 uniform. The gradual widening of the first radiator 3 towards the end also helps to improve the surface current distribution. 5, curve 51 represents the radiation pattern (Radiation Pattern) when the third section 33 is not present in this embodiment, and curve 52 represents the radiation pattern when the third section 33 is present in this embodiment. The third section 33 can increase the radiation gain by 0.5-1 dBi.

Furthermore, since the folded printed antenna of the present invention is bent so that its end is close to the ground plane 2 , the surface current distribution at the end of the first radiator 3 can be evenly distributed, thereby improving the radiation gain. Furthermore, since the first and second radiators 3, 4 of the present invention and the ground plane 2 are located on the same circuit board 1, rather than being located on two vertical circuit boards respectively, the height of the present invention is the thickness of the circuit board 1 , without causing an additional height increase. However, the present invention is connected to the circuit (not shown) through the transmission line 6 and completed together with the transmission line 6 , which omits the steps of assembling, welding and adding wires compared to the conventional ones. Therefore can really reach the object of the present invention.

Claims (14)

1. a printing folding Stacked formula antenna is applicable to a circuit to be connected, and it is characterized in that:

One circuit board comprises the feed-through assembly that two two surfaces and that lay respectively at this circuit board can make this two surface connect, and this circuit is positioned on this circuit board;

One ground plane is positioned on the surface of this circuit board;

One first radiant body, be positioned on another surface of this circuit board, and be used to determine bandwidth, and comprise one first section, one second section and one the 3rd section that connects in regular turn, and widen gradually toward the 3rd section by this first section, this the first section view field edge from this ground plane extends outward, and its end near the view field of this ground plane is connected with this circuit, and end of second section of the other end and this is connected, other end of second section of an end of the 3rd section and this is connected, and the 3rd section the other end is near the view field of this ground plane; And

One second radiant body, be positioned on the identical surface of this circuit board with this first radiant body, and be used to adjust the input impedance of this printing Zhe Stacked formula antenna, and one end and this first radiant body first section be connected, and the other end is connected with this ground plane via the feed-through assembly of this circuit board.

2. printing Zhe Stacked formula antenna according to claim 1 is characterized in that the length of this first radiant body is near 1/4 wavelength of this bandwidth.

3. printing Zhe Stacked formula antenna according to claim 1, it is characterized in that, this the first section view field edge from this ground plane extends outward, this second section is extended from this end bending away from the view field of this ground plane of first section, and the 3rd section from this second section extends toward view field's bending of this ground plane away from this end of first section.

4. as the printing Zhe Stacked formula antenna as described in the claim 3, it is characterized in that second section of this first radiant body is vertical with this first section in fact, and the 3rd section vertical with this second section in fact.

5. printing Zhe Stacked formula antenna according to claim 1 is characterized in that, first section of this first radiant body and second section are all rectangular.

6. printing Zhe Stacked formula antenna according to claim 1 is characterized in that the 3rd section of this first radiant body is rectangular.

7. printing Zhe Stacked formula antenna according to claim 1 is characterized in that the 3rd section of this first radiant body is rounded.

8. printing Zhe Stacked formula antenna according to claim 1 is characterized in that, the 3rd section of this first radiant body is trapezoidal.

9. printing Zhe Stacked formula antenna according to claim 1 is characterized in that the 3rd section of this first radiant body is L-shaped.

10. printing Zhe Stacked formula antenna according to claim 1 is characterized in that, the 3rd section of this first radiant body is and clips the trapezoidal of an acute angle.

11. printing Zhe Stacked formula antenna according to claim 1 it is characterized in that second section width of this first radiant body is not less than this width of first section, and the 3rd section width is greater than this width of second section.

12. printing Zhe Stacked formula antenna according to claim 1, it is characterized in that, this second radiant body comprises one the 4th section and one the 5th section, the 4th section from extending outward between first section the two ends of this first radiant body, and its bearing of trend is identical with second section of this first radiant body in fact, and the 5th section from the 4th section bend away from this end of first section extended, and is electrically connected with this ground plane.

13. the printing Zhe Stacked formula antenna as described in the claim 12 is characterized in that, the 4th section of this second radiant body vertical with first section of this first radiant body in fact, and the 5th section of this second radiant body is vertical with the 4th section in fact.

14. the printing Zhe Stacked formula antenna as described in the claim 12 is characterized in that, the 4th section of this second radiant body and the 5th section are all rectangular.

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