TW201414083A - Board antenna - Google Patents

Abstract

This invention relates to a board antenna. The board antenna comprises a circuit board, a metal trace printed on the circuit board, and a coaxial wire soldered to the metal trace. The coaxial wire has a centre conductor and a grounding coat insulative wrapped out of the conductor. The metal trace includes a metal loop having two adjacent feeding ends, a first radiator and a second radiator positioned in the metal loop. The first radiator and second radiator are respectively connected to each of the feeding ends. The centre conductor is soldered to the feeding end connected to the first radiator. The grounding coat is soldered to the feeding end connected to the second radiator.

Description

Board antenna

The present invention relates to a circuit board antenna, and more particularly to a circuit board antenna mounted inside an electronic device for wireless transmission.

The function of electronic devices with wireless communication has become a common phenomenon. Antennas, as an essential component of wireless communication, are increasingly used in electronic devices. With the miniaturization of electronic devices, the development of aesthetics, and advances in antenna technology, more and more antennas are built into electronic devices. In the prior art, a thin-film antenna is usually produced by a method of manufacturing a printed circuit board, and a desired antenna shape is produced by a technique such as etching or laser irradiation.

A circuit board antenna is disclosed in US Pat. No. 7,639,194, which is a dual-frequency loop antenna that is used on a small electronic mobile device to transmit two adjacent frequency bands, including a metal circuit, a radiator, and a ground. The area, which occupies most of the space of the board, is not conducive to space saving.

The main object of the present invention is to provide a circuit board antenna which is simple in structure, stable in function and space-saving.

To achieve the above object, the present invention provides a circuit board antenna comprising a substrate, a radiator disposed on the substrate, and a signal transmission line electrically connected to the radiator, the signal transmission line including a mask layer and a center conductor, the radiation The body comprises an annular metal strip, a first radiating element and a second radiating element symmetrically disposed in the annular metal strip, and the annular metal strip is partially disconnected to form two end points of the first feeding point and the second feeding point respectively The center conductor of the signal transmission line is electrically connected to the first feeding point and the first radiating element, and the mask layer is electrically connected to the second feeding point and the second radiating element.

Compared with the prior art, the circuit board antenna provided by the invention has the advantages of simple manufacturing method, low cost, stable function and small volume.

Referring to the first and second figures, a circuit board antenna 100 consistent with the present invention is disclosed. The circuit board antenna 100 includes a substrate 30, a radiator 10 disposed on one side of the substrate 30, and a signal transmission line 20 electrically connected to the radiator 10. The signal transmission line 20 includes a center conductor 21 and a mask layer 22 that surrounds the center conductor 21. A coaxial cable is generally preferred. The radiator 10 includes an annular metal strip 14, a parasitic element 13 disposed independently of the annular metal strip 14, and a first radiating element 11 and a second radiating element 12 symmetrically disposed within the endless metal strip 14, annular The metal strip 14 is partially disconnected to form two end points of the first feed point 141 and the second feed point 142 respectively. The center conductor 21 of the signal transmission line 20 and the first feed point 141 and the first radiating element 11 are electrically connected. Connected, the mask layer 22 is electrically connected to the second feed point 142 and the second radiating element 12.

In the present embodiment, the first radiating element 11 and the symmetrically disposed second radiating element 12 and the parasitic element 13 are each in the shape of an elongated metal foil and are located in the same side of the substrate 30 as the annular metal strip 14. Preferably, the parasitic element 13 is arranged in parallel with the first radiating element 11 and the second radiating element 12. The first radiating element 11 and the second radiating element 12 are separately disposed, and the first radiating element 11 is adjacent to the second radiating element 12 and is connected to the first feeding point 141 through the metal microstrip 101, and the second radiating element 12 is adjacent to the first One end of the radiating element 11 is electrically connected to the second feeding point 142 through the metal microstrip 102.

Please refer to the third and fourth figures, which are simulation diagrams of the return loss of the board antenna 100 in the vicinity of 2.45 GHz and 5 GHz to 6 GHz, respectively, and the horizontal axis is the frequency in units of gigahertz (GHz). ), the vertical axis is the loss ratio in dB. It can be seen from the figure that although the antenna disclosed by the present invention has a small volume, it still has a good performance in the vicinity of the 2.45 GHz frequency and the bandwidth loss of less than -10 dB in the frequency range of 5 GHz to 6 GHz. Applicable to the three working bands of IEEE 802.11a/b/g as defined by the Institute of Electrical and Electronics Engineers (IEEE).

The annular metal strip 14 corresponds to a low frequency band, and the first radiating element 11 and the second radiating element 12 and the parasitic element 13 correspond to a high frequency band. The electrical length of the annular metal strip 14 is about one wavelength corresponding to the center frequency of the working frequency band, that is, the frequency of 2.45 GHz, and the length of the parasitic element 13 is about half of the wavelength corresponding to the center frequency of the corresponding working frequency band, that is, 5.5 GHz, symmetrically set. The lengths of the first radiating element 11 and the second radiating element 12 are both about one quarter of the wavelength corresponding to the center frequency of the operating frequency band, that is, the frequency of 5.5 GHz.

In this embodiment, the annular metal strip 14 is substantially rectangular and has oppositely disposed wide sides and narrow sides. The first radiating element 11 and the second radiating element 12 are disposed parallel to the wide side, the first feeding point 141 and the first The two feed points 142 are disposed on the long sides. Preferably, the distance between the first feeding point 141 and the second feeding point 142 is the same as the distance between the first radiating element 11 and the second radiating element 12, so that the metal microstrip 101 is arranged in parallel with the metal microstrip 102. .

Referring to the fifth and sixth figures, the simulation of the circularly polarized radiation pattern generated by the left and right board antennas 100 when the board antenna 100 is symmetrically disposed on both sides of the vertically placed display device is simulated. Figure. The simulation curve 145 is an experimental simulation diagram of the radiation pattern generated in the horizontal plane when the circuit board antenna 100 is placed on the right side of the television and operates at a frequency of 2.45 GHz. The simulation curve 146 is that the circuit board antenna 100 is placed on the left side of the television and operates on An experimental simulation of the radiation pattern generated in the horizontal plane at 2.45 GHz; the simulation curve 115 is an experimental simulation of the radiation pattern generated in the horizontal plane when the circuit board antenna 100 is placed on the right side of the television and operates at 5.5 GHz. Analog curve 116 is an experimental simulation of the radiation pattern produced by the board antenna 100 in the horizontal plane when placed on the left side of the television and operating at 5.5 GHz. It can be seen that the two circuit board antennas 100 symmetrically disposed on both sides of the television can produce a relatively ideal circular polarization effect. Of course, the circuit board antenna 100 is not limited to use on a television set.

The circuit board antenna 100 is responsible for connecting the center conductor 21 and the mask layer 22 at both ends of the low-frequency annular metal strip 14, respectively, and the formed loop forms a short circuit effect on the feeding of the DC weak current, whereby the board antenna 100 pairs The surrounding static electricity has strong anti-interference ability, which is beneficial to reduce the distance between the circuit board antenna 100 and other electronic devices to achieve space saving effect.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above-mentioned embodiments are merely preferred embodiments of the present invention, and the scope of the present invention is not limited to the foregoing embodiments, and those skilled in the art will be able to make equivalent modifications or variations in accordance with the spirit of the present invention. It should be covered by the following patent application.

100. . . Board antenna

10. . . Radiator

101,102. . . Metal microstrip

11. . . First radiating element

12. . . Second radiating element

13. . . Parasitic element

14. . . Ring metal strip

141. . . First feed point

142. . . Second feed point

115,116,145,146. . . Simulation curve

20. . . Signal transmission line

twenty one. . . Center conductor

twenty two. . . Mask layer

30. . . Substrate

The first figure is a perspective view of a circuit board antenna in accordance with the present invention.

The second figure is a front view of the circuit board antenna substrate and the radiator shown in the first figure.

The third and fourth figures are simulations of the return loss of the board antenna shown in the first figure as a function of frequency.

The fifth and sixth figures are simulations of the circularly polarized radiation pattern of the circuit board antenna shown in the second figure.

100. . . Board antenna

10. . . Radiator

20. . . Signal transmission line

twenty one. . . Center conductor

twenty two. . . Mask layer

30. . . Substrate

Claims (8)

A circuit board antenna comprising:
The substrate is in the form of a flat sheet;
The radiator is disposed on the substrate, and the radiator includes an annular metal strip, a first radiating element and a second radiating element symmetrically disposed in the annular metal strip, and the annular metal strip is partially disconnected to form the first feeding And a second transmission point; the signal transmission line includes a center conductor and a mask layer; wherein the center conductor of the signal transmission line is electrically connected to the first feed point and the first radiating element The mask layer is electrically connected to the second feed point and the second radiating element. The circuit board antenna of claim 1, wherein the radiator further comprises a parasitic element disposed independently of the annular metal strip. The board antenna of claim 2, wherein the parasitic element has a length of about one-half of a wavelength corresponding to a frequency of 5.5 GHz. The circuit board antenna of claim 2, wherein the parasitic element is disposed in parallel with the first radiating element and the second radiating element. The circuit board antenna of claim 1, wherein the first radiating element and the second radiating element are separately disposed, and the first radiating element is adjacent to the first feeding point and adjacent to the first feeding point. An end of the second radiating element adjacent to the first radiating element is coupled to the second feed point. The circuit board antenna of claim 5, wherein the first radiating element and the second radiating element have a length of about one quarter of a wavelength corresponding to a working frequency of 5.5 GHz. The circuit board antenna of claim 1, wherein the annular metal strip is substantially rectangular and has oppositely disposed wide sides and narrow sides, and the first radiating element and the second radiating element are disposed parallel to the wide side. . The circuit board antenna of claim 1, wherein the annular metal strip has an electrical length of about 2.45 GHz operating frequency corresponding to a wavelength.