TWI641184B - Fm antenna structure - Google Patents

Abstract

The present invention discloses an FM antenna structure including at least one wound coil antenna and at least one solid material. The wound coil antenna has a front end that is a signal feed point. The solid material is placed inside the wound coil antenna and occupies only a portion of the wound coil antenna, such that the portion of the wound coil antenna has the solid material inside, and the interior of the portion is hollow . Thereby, the present invention has the advantages of short antenna length, low signal energy loss, and easy impedance matching.

Description

FM antenna structure

The present invention relates to an antenna structure, and more particularly to a vehicle FM antenna structure.

The shark fin antenna of the known technology is fixed on the top of the car and electrically connected to the car radio for listening to FM radio programs. The inside of the shark fin antenna has an antenna made of a conductive metal. For example, Taiwan Patent No. M457311 "Improved Shark Fin Antenna Structure" patent discloses that a shark fin antenna includes a circuit board and is soldered to the circuit board. A core wound wire coil antenna for receiving FM signals. The inside of such a core-wound coil antenna is completely occupied by the magnetic core, so that many of the received FM signal energy is absorbed by the magnetic core to cause energy loss.

The antenna structure disclosed in Taiwan Patent No. M297054 is composed of two vertical side-by-side half-wavelength antennas, each half-wavelength antenna being a loop formed by a metal wire being swirled. Another shark fin car antenna from Taiwan Announcement No. I520433 also discloses a stepped ladder antenna that is bent in a continuous ladder shape and gradually increases in the backward direction. The antennas disclosed therein are all the hollow coiled coil antennas inside, and the hollow-wound antennas have less energy loss than the aforementioned core-wound coil antennas, but need to be relatively long. length.

It can be seen that the conventional magnetic core wound coil antenna has the need for improvement in energy loss and length.

Although the conventional FM wound coil antenna has various structures as described above, there is still a need to continue to develop a new FM wound coil antenna having a shorter length, less energy loss, and easier impedance matching. The invention provides an FM antenna structure comprising at least one wound coil antenna and at least one solid material. The wound coil antenna has a front end that is a signal feed point. The solid material is placed inside the wound coil antenna and occupies only a portion of the wound coil antenna, such that the portion of the wound coil antenna has the solid material inside, and the interior of the portion is hollow . Wherein, the section of the wound coil antenna that is hollow inside may be further bent so that the wound coil antenna is in a meandering shape or an arc shape.

Further, the solid material of the present invention may be optionally placed in one of the front section, the middle section or the rear section of the wound coil antenna, preferably disposed inside the rear section. Wherein, after the wound coil antenna is straightened, the middle section is the longest, and the second section is the rear section, and the front section is the shortest.

In addition, the FM antenna structure of the present invention further includes another solid material such that the inside of the wound coil antenna has two solid materials and a hollow portion. Wherein, the two solid materials are respectively placed in the front and rear sections of the wound coil antenna, and the hollow portion is the middle section of the wound coil antenna.

In addition, the present invention also provides another FM antenna structure including a dipole antenna and two solid materials. The dipole antenna includes the same two-wound coil antenna, and the two-wound coil antennas are arranged in a straight line, wherein a front end of a wound coil antenna is used as a signal feed point, and a front end of another wound coil antenna It is grounded, and the front ends of the two wound coil antennas are facing each other. The two solid materials are respectively disposed inside the rear portion of the two wound coil antennas, such that a portion of each of the wound coil antennas has the solid material inside, and a portion of the inner portion of the loop is hollow. Wherein, each of the wound coil antennas can be bent into an L shape, respectively, so that the two solid materials are opposite each other.

Furthermore, the FM antenna structure of the present invention further includes two other solid materials, which are respectively placed inside the rear portion of the two wound coil antennas, and the other two solid materials are respectively placed correspondingly. Inside the front section of the two-wound coil antenna, each of the wound coil antennas has only the inside of the front and rear sections occupied by the corresponding solid material, and the inside of the middle section is hollow.

Further, each of the solid materials in the above FM antenna structure of the present invention may be a magnetic core or a ceramic material.

Compared with the prior art, the FM antenna structure of the present invention adopts the practice of "making the wound coil antenna portion hollow and partially occupied by the solid material", so that it has the advantages of short length, low energy loss, and easy impedance matching.

1 and 2 show a first preferred embodiment of the FM antenna structure of the present invention, which is essentially an FM vehicle shark fin antenna for receiving FM signals. More specifically, the FM antenna structure of the present invention includes a shark fin casing 1, a circuit board 2 disposed in the shark fin casing 1, a wound coil antenna 3 connected to the circuit board 2, and A solid material 4. A surface of the circuit board 2 has a conductive pad 20 for collecting radio signals of a predetermined bandwidth, in this embodiment for collecting FM signals. A front end 30 of the wound coil antenna 3 is soldered to the conductive pad 20, whereby the wound coil antenna 3 is fixed to the circuit board 2. The front end 30 of the wound coil antenna 3 is used as a signal feed point, which is connected to a connector C by a wire L, and the connector C can be screwed to a coaxial cable (not shown), so that The FM signal collected by the wound coil antenna 3 can be fed into a radio, such as a car radio, via the front end 30, the wire L, the connector C, and the coaxial cable.

The solid material 4 is placed inside a rear section 33 of the wound coil antenna 3 such that the rear section 33 of the wound coil antenna 3 has the solid material 4 inside, and the remaining sections are hollow. The solid material 4 can also be modified to be placed in the middle section 32 or the front section 31 of the wound coil antenna 3, and the remaining paragraphs are hollow, but are preferably placed in the rear section 33 because when the solid material 4 is located in the winding In the rear section 33 of the coil antenna 3, the energy absorbed from the FM signal is relatively low, so that the energy loss of the FM signal can be reduced.

The solid material 4 comprises a magnetic core material and a dielectric material, such as a magnetic core or a ceramic member, and the magnetic core may be made of a sintered metal oxide composed of a mixture of various iron oxides, for example, manganese-zinc ferrite. A magnetic core made of a body or a nickel-zinc ferrite. In this embodiment, the solid material 4 is a hollow cylinder, but may also be a solid cylinder or a hollow or solid cylinder of other shapes. In any case, by the arrangement of the solid material 4, the applicable frequency of the antenna structure of the present invention can be adjusted to 88 to 108 MHz, and the length of the wound coil antenna 3 can be shortened and the receiving performance can be improved. Wherein, the length of the solid material 4 is inversely proportional to the total length of the antenna.

Since the solid material 4 occupies only a portion of the wound coil antenna 3, the other portion of the wound coil antenna 3 (i.e., the inner hollow portion) has a property of being bendable. In the embodiment, the wound coil antenna 3 is bent into three paragraphs, which are respectively connected to the front end 30 and stand up to the front section 31 of the circuit board 2, continue to the front section 31 and are transverse to the a middle section 32 above the circuit board 2, and a rear section 33 contiguous with the middle section 32 and standing upright on the circuit board 2, the rear section 33 has an end 330 fixed to the circuit board 2 and not formed with the front end 30 Electrical connections. Preferably, the circuit board 2 has a separate pad 21, the independent pad 21 is not electrically connected to the conductive pad 20, and the end 330 is soldered to the independent pad 21, only to fix the rear section. 33.

In the first and second figures, the wound coil antenna 3 is bent to be substantially ㄇ-shaped, but may be inverted U-shaped or curved. In addition, the lengths of the front section 31 (including the front end 30), the middle section 32, and the rear section 33 (including the end 330) of the wound coil antenna 3 after straightening are preferably about 172 mm, 282 mm, and 188 mm, respectively. 642mm, wherein the middle section 32 is the longest, the second section is the rear section 33, and the front section 31 is the shortest. The number of coil turns of the front section 31 (including the front end 30), the middle section 32, and the rear section 33 (including the end 330) of the wound coil antenna 3 is preferably about 5.5, 9 and 6 respectively (corresponding lengths respectively) It is 2.5 cm, 3.5 cm, and 2 cm), of which 32 is the most in the middle, and 33 is in the back, while the first 31 is the least.

Referring to FIG. 3, there is shown a second preferred embodiment of the FM antenna structure of the present invention, which is substantially identical to the first preferred embodiment described above, except that the second preferred embodiment has a solid state. The material 4a, the solid material 4a is located inside the front section 31, and may optionally occupy or partially occupy the inside of the front section 31 as needed. Among them, the portion of the middle portion 32 still maintains all hollow.

Referring to FIG. 4, there is shown a third preferred embodiment of the FM antenna structure of the present invention, which differs from the first preferred embodiment only in that the wound coil antenna 3 is linear and inclined. The circuit board 2 is such that its end 330 is suspended.

Referring to FIG. 5, a fourth preferred embodiment of the FM antenna structure of the present invention is shown to be substantially identical to the third preferred embodiment described above, except that the fourth preferred embodiment has one more The solid material 4b is located inside the front section 31 of the wound coil antenna 3, and may optionally occupy or partially occupy the inside of the front section 31 as needed. Among them, the portion of the middle portion 32 still maintains all hollow.

Referring to FIG. 6, a fifth preferred embodiment of the FM antenna structure of the present invention is shown. The FM antenna structure constitutes a dipole antenna having better radiation efficiency, and includes the same two-wound coil antenna 3 and the same Two solid materials 4, and each solid material 4 is correspondingly located inside the rear section 33 of each of the wound coil antennas 3, such that each of the wound coil antennas 3 has only its inner portion 33 occupied by the corresponding solid material 4, The remaining paragraphs are hollow. The two wound coil antennas 3 are arranged in a straight line, and the front ends 30 thereof are soldered to the circuit board 2, and the ends 330 thereof are suspended. The two front ends 30 are opposite to each other, and the front end 30 of one of the wound coil antennas 3 is connected to a signal feeding point, and the front end 30 of the other wound coil antenna 3 is connected to the ground. Taking a coaxial cable that is generally used as an antenna connection cable as an example, one of the wound coil antennas 3 is connected to a central copper wire inside the coaxial cable, and the other wound coil antenna 3 is connected to the coaxial cable. Outer metal mesh.

Please refer to FIG. 7, which shows a sixth preferred embodiment of the FM antenna structure of the present invention, which is substantially the same as the fifth preferred embodiment, except that two solid materials 4c are added, and more The two solid materials 4c are respectively disposed inside the front section of each of the wound coil antennas 3 such that the front section 31 and the rear section 33 of each of the wound coil antennas 3 are occupied by the corresponding solid material 4, Only the middle section 32 is hollow.

Referring to Figure 8, there is shown a seventh preferred embodiment of the FM antenna structure of the present invention which is substantially identical to the fifth preferred embodiment except that the hollow segments of each of the wound coil antennas 3 are The bending causes each of the wound coil antennas 3 to be bent into an L shape, and the two solid materials 4 are aligned.

In summary, the FM antenna structure of the present invention is partially occupied by the solid material 4 due to the inside of the wound coil antenna 3, and is partially hollow, so that it is completely filled with the magnetic core. The FM wound coil antenna, the FM signal received by the wound coil antenna 3 of the present invention has less energy loss, and the conventional magnetic coreless FM wound coil antenna is hollow relative to the inside. With the arrangement of the solid material 4, the wound coil antenna 3 of the present invention is not only short in length but also relatively easy to achieve impedance matching.

1‧‧‧Shark fin shell

2‧‧‧ boards

20‧‧‧Electrical pads

21‧‧‧Independent pads

3‧‧‧Wind coil antenna

30‧‧‧ front end

31‧‧‧ front section

32‧‧‧ middle section

33‧‧‧After

End of 330‧‧‧

4, 4a, 4b, 4c‧‧‧ solid materials

L‧‧‧ wire

C‧‧‧Connector

Figure 1 is a perspective view of a first preferred embodiment of the present invention. Figure 2 is a side elevational view of the first preferred embodiment of the present invention. Figure 3 is a side view of a second preferred embodiment of the present invention. Figure 4 is a perspective view of a third preferred embodiment of the present invention. Figure 5 is a perspective view of a fourth preferred embodiment of the present invention. Figure 6 is a perspective view of a fifth preferred embodiment of the present invention. Figure 7 is a perspective view of a sixth preferred embodiment of the present invention. Figure 8 is a perspective view of a seventh preferred embodiment of the present invention.

Claims (9)

An FM antenna structure comprising: a wound coil antenna having a front end, the front end being a signal feed point; and a solid material being placed inside the wound coil antenna and occupying only the winding type a portion of the coil antenna, such that the portion of the coiled coil antenna has the solid material inside, and the interior of the portion of the loop is hollow; wherein the hollow portion of the wound coil antenna is bent, so that The wound coil antenna has a meandering shape or an arc shape. The FM antenna structure of claim 1, wherein the wound coil antenna has a front section connecting the front end, a middle section connecting the front section, and a rear section continuing the middle section, wherein the solid material system Wear one of the front section, the middle section or the back section. The FM antenna structure of claim 2, wherein after the wound coil antenna is straightened, the middle section is longest, and the second section is the rear section, and the front section is the shortest. The FM antenna structure of claim 1, further comprising another solid material, the other solid material being disposed inside the wound coil antenna and occupying only a portion of the wound coil antenna The part of the winding coil antenna has the two solid materials inside, and the inside of the partial passage is hollow. The FM antenna structure of claim 4, wherein the wound coil antenna has a front section connecting the front end, a middle section connecting the front section, and a rear section continuing the middle section, wherein the two solid materials They are respectively placed in the front section and the rear section, and the middle section is hollow. An FM antenna structure includes: a dipole antenna comprising the same two-wound coil antenna, the two wound coil antennas are arranged in a straight line, wherein a front end of a wound coil antenna is used as a signal feeding point, and The front end of a wound coil antenna is grounded, and the front ends of the two wound coil antennas are facing each other; two solid materials are respectively placed inside the rear portion of the two wound coil antennas, so that The portion of each of the wound coil antennas has the solid material inside, and the inside of the portion is hollow. The FM antenna structure of claim 6, wherein each of the wound coil antennas is bent into an L-shape, and the two solid materials are opposite to each other. The FM antenna structure of claim 6, further comprising two other solid materials, the two solid materials being respectively disposed inside the rear portion of the two wound coil antennas, the other two solid materials They are respectively placed inside the front section of the two-wound coil antenna, so that each of the wound coil antennas is only occupied by the corresponding solid material in the front and rear sections, and the interior of the middle section is hollow. The FM antenna structure of claim 1, wherein the solid material is a magnetic core or a ceramic material.