TWI445246B - Built-in fm transmitting antenna applied to a mobile device - Google Patents

Description

Built-in FM transmitting antenna for mobile devices

The invention relates to an FM transmitting antenna, in particular to a built-in FM transmitting antenna applied to a mobile device.

The Frequency Modulation (FM) broadcasting system is a broadcasting system that transmits sound signals by using frequency modulation technology. Compared with the Amplitude Modulation (AM) broadcast system, the broadcast signal of the FM broadcast system has many advantages, such as a constant envelope, a resistance to nonlinear distortion, and a Fading effect. Therefore, the signal quality of the FM broadcasting system is better, and the FM broadcasting system can transmit the signals of the left and right channels, thus having a stereo effect.

The receiving end (radio) of the FM broadcasting system receives the FM broadcast signal through the antenna, and after outputting the frequency, demodulation, etc., outputs the sound signal, and the main key affecting the sound quality output by the radio is the receiving efficiency of the antenna. The receiving antennas conventionally used in FM broadcasting systems are mostly exposed antenna structures, and the antenna type of the rod-type monopole antenna and the polypole antenna of polyethylene (Polyethelyne, PE) is mainly used.

Please refer to the first figure and the second figure, which are respectively a schematic diagram of a conventional one-pole antenna 1a and an FM dipole antenna 2a with a polyethylene. The pull rod type monopole antenna 1a is usually fixed at a corner of the portable audio or handheld radio case, and when the broadcast program is to be listened to, the pull rod type monopole antenna 1a needs to be pulled out to a certain length, when not in use, The rod-type monopole antenna 1a can be retracted and housed to save space. Since the drawbar type monopole antenna 1a has to be pulled out to a certain length (about 76 cm) when listening to the broadcast program, the tie rod type monopole antenna 1a is easily broken by an external force, and takes up space and deteriorates the appearance. In contrast, the FM dipole antenna 2a of the outer polyethylene is generally used in a stationary audio apparatus, which can avoid the problem of being broken by an external force. However, the FM dipole antenna 2a of the outer polyethylene is expensive (about one dollar), and it is necessary to connect the radiating metal wires 22a, 24a of the FM dipole antenna 2a and the acoustic antenna socket through a long transmission line 20a. It is very easy to cause the FM dipole antenna 2a to be entangled, knotted, etc., and it is also inconvenient to use.

In short, the rod-type monopole antenna 1a has a large antenna size, and is exposed above the portable or hand-held sound and the radio casing in practical applications, and is easily broken by an external force, and takes up space and damages the appearance. The FM dipole antenna 2a has a high production cost and is very easy to be entangled, knotted, and the like. These antenna architectures not only increase the user's inconvenience, but also destroy the overall appearance of the product. In order to solve the problems of inconvenient use and damage aesthetics of the above-mentioned exposed antenna, it is necessary to design a built-in antenna whose impedance and bandwidth satisfy the operation of the frequency modulation band.

Among them, Taiwan Patent No. M283445 proposes a "mobile phone with an FM antenna", which discloses a reduced-frequency FM antenna structure which is assembled on both sides and the bottom of the body of the mobile phone. Such a structure is usually because the antenna is too close to the ground plane of the system, the inductance and reactance of the antenna are too large, and the impedance matching is deteriorated, which affects the receiving quality of the FM antenna.

In addition, Taiwan Patent No. 200620752 proposes an "antenna for mobile terminal and a mobile terminal", and the antenna disclosed therein is composed of a plurality of different units, including an antenna element of an exposed casing and a metal coil housed inside the casing. Such a design needs to combine the mobile phone antenna with the metal coil inside the casing, thus increasing the manufacturing cost and complexity of the antenna.

In addition, US Patent Publication No. US 2006/0111163 A1 proposes "FM transmitting antenna device in a handheld terminal", the antenna of which is mainly attached to a surface of a hand-held terminal, and the antenna is connected to the FM by a flexible circuit board (FPC). launcher. Such a structure is complicated, and the antenna area is small and the radiation characteristics are poor.

The reason is that the present inventors have felt that the above-mentioned defects can be improved, carefully observed and studied, and in conjunction with the application of the theory, a present invention which is reasonable in design and effective in improving the above-mentioned defects is proposed.

The technical problem to be solved by the present invention is to provide a built-in FM transmitting antenna applied to a mobile device.

In order to solve the above technical problem, according to one aspect of the present invention, a built-in FM transmitting antenna for a mobile device is provided, comprising: a substrate unit, a first antenna unit, a conductive unit, and a second day Line unit. The substrate unit has a circuit substrate, at least one ground layer disposed on the circuit substrate, and a plurality of conductive pads disposed on the circuit substrate. The first antenna unit is disposed above the substrate unit and substantially parallel to the substrate unit. The conductive unit is electrically connected between the substrate unit and the first antenna unit. The second antenna unit is directly disposed on the upper edge of the circuit substrate of the substrate unit, wherein the two ends of the second antenna unit are electrically connected between the two conductive pads, and the two ends of the second antenna unit are respectively transmitted through The two conductive pads are electrically connected to a frequency modulation chip module and a conductive unit, respectively.

In order to solve the above technical problem, according to one aspect of the present invention, a built-in FM transmitting antenna for a mobile device is provided, comprising: a substrate unit, a first antenna unit, a conductive unit, and a second day Line unit. The substrate unit has a circuit substrate mounted in the mobile device, at least one ground layer disposed on the circuit substrate, and a plurality of conductive pads disposed on the circuit substrate. The first antenna unit is disposed above the substrate unit and attached or formed on an inner surface of the outer casing of the mobile device, wherein the first antenna unit is substantially parallel to the substrate unit. The conductive unit is electrically connected between the substrate unit and the first antenna unit. The second antenna unit is directly disposed on the upper edge of the circuit substrate of the substrate unit, wherein the two ends of the second antenna unit are electrically connected between the two conductive pads, and the two ends of the second antenna unit are respectively transmitted through The two conductive pads are electrically connected to a frequency modulation chip module and a conductive unit, respectively.

Therefore, the present invention has the beneficial effects that at least one ground layer, the first antenna unit and the second antenna unit of the substrate unit are matched with each other to form an equivalent circuit similar to the resonator. In other words, the built-in FM transmitting antenna of this embodiment is a composite antenna design, which includes a second antenna unit (having an inductance-generating characteristic) and a substantially flat substrate unit (ie, having a ground layer) A first antenna unit (similar to a plate capacitor having a capacitive characteristic) above the system board) for forming an equivalent circuit similar to an RLC resonator.

For a better understanding of the features and technical aspects of the present invention, reference should be made to the accompanying drawings.

Please refer to the third figure, which is a three-dimensional combination diagram of a first embodiment of a built-in FM transmitting antenna applied to a mobile device of the present invention. As shown in the figure, the first embodiment of the present invention provides a built-in FM transmitting antenna for a mobile device, comprising: a substrate unit 1, a first antenna unit 2, a conductive unit 3, and a second day. Line unit 4.

The substrate unit 1 has a circuit board 10 , at least one ground layer 11 disposed on the circuit board 10 , and a plurality of conductive pads 12 disposed on the circuit board 10 . In the example of the embodiment, the at least one grounding layer 11 and the conductive pads 12 are disposed on the upper surface of the circuit substrate 10, and the conductive pads 12 are not covered by the at least one ground layer 11 Covered, and the upper surface of the circuit substrate 10 has one of the regions being a bare region 100 not covered by the at least one ground layer 11.

Furthermore, the first antenna unit 2 is disposed above the substrate unit 1 and substantially parallel to the substrate unit 1, and the best implementation is that the first antenna unit 2 is completely parallel to the substrate unit 1, and the first The area of the antenna unit 2 is larger than the area of the substrate unit 1. In the example of the embodiment, the first antenna unit 2 can be a metal plate, a metal film or any conductive material disposed above the substrate unit 1 and substantially parallel to the substrate unit 1.

In addition, the conductive unit 3 has a first end 3A and a second end 3B opposite to the first end 3A, and the first end 3A and the second end 3B are connected to the substrate unit 1 and the first antenna unit 2, respectively. . Therefore, the conductive unit 3 is electrically connected between the substrate unit 1 and the first antenna unit 2 to serve as an electrical connection bridge between the substrate unit 1 and the first antenna unit 2. In the example given in this embodiment, the conductive unit 3 can be a flexible member such as a spring, a spring or any elastic material. In other words, in this embodiment, the electrical connection between the substrate unit 1 and the first antenna unit 2 can be achieved by using only a one-piece (or integrally formed) flexible element, without using a complicated structure. The connector serves as an electrical connection bridge between the substrate unit 1 and the first antenna unit 2.

In addition, the second antenna unit 4 is directly disposed on the upper edge of the circuit substrate 10 of the substrate unit 1 (that is, at the edge of the upper surface of the circuit substrate 10), that is, the second antenna unit 4 is not disposed on the at least one ground layer. 11 is disposed on the exposed area 100 of the circuit substrate 10, wherein the second antenna unit 4 can be disposed between the substrate unit 1 and the first antenna unit 2, and of course, the first antenna unit 2 can be avoided. The position above the second antenna unit 4 is such that the top of the second antenna unit 4 is not obscured by the first antenna unit 2. In addition, the two ends (4A, 4B) of the second antenna unit 4 are electrically connected between the two conductive pads 12, respectively, and the two ends (4A, 4B) of the second antenna unit 4 respectively pass through the above. The two conductive pads 12 are electrically connected to the FM chip module F and the conductive unit 3 respectively. In addition, the present invention can reduce the operating frequency of the antenna through the second antenna unit 4, so that the built-in FM transmitting antenna can Produces good radiation characteristics.

Thereby, at least one ground layer 11, the first antenna unit 2 and the second antenna unit 4 of the substrate unit 1 are matched with each other to form an equivalent circuit similar to a resonator. In other words, the built-in FM transmitting antenna of the present embodiment is a composite antenna design, which includes a second antenna unit 4 (having an inductance-generating characteristic) and a substantially flat unit 1 (ie, has a connection) The first antenna unit 2 (similar to a panel capacitor having a capacitive characteristic) above the system board of the formation 11 is used to form an equivalent circuit similar to the RLC resonator. In addition, because the resonant frequency of the resonator is Therefore, the present invention can control the value of the inductance generated by the second antenna unit 4 and the capacitance value generated by the first antenna unit 2 (this capacitance value can be controlled by the size of the area of the first antenna unit 2), that is, The realization of a built-in FM transmitting antenna can be achieved.

Please refer to FIG. 4A , which is a top view showing the electrical connection of the first antenna unit and the conductive unit according to the second embodiment of the present invention. The maximum difference between the second embodiment and the first embodiment is shown in FIG. 3 and FIG. 4A. In the second embodiment, the first antenna unit 2 has a second end 3B adjacent to the conductive unit 3. The slit 20A, the design of the slit 20A contributes to the improvement of the "inductance value" of the input impedance of the FM transmitting antenna.

Please refer to FIG. 4B , which is a top view showing the electrical connection between the first antenna unit and the conductive unit according to the third embodiment of the present invention. The third embodiment and the fourth B diagram show the greatest difference between the third embodiment and the first embodiment in that, in the third embodiment, the first antenna unit 2 has a second end 3B adjacent to the conductive unit 3. The opening 20B, the design of the opening 20B contributes to the improvement of the "capacitance value" of the input impedance of the FM transmitting antenna.

Please refer to FIG. 5A, which is a perspective view of a second antenna unit according to a fourth embodiment of the present invention. The maximum difference between the fourth embodiment and the first embodiment is shown in the third and fifth A diagrams. The fourth embodiment discloses the first detailed embodiment of the second antenna unit 4. In the fourth embodiment, the second antenna unit 4 can be a chip antenna, and includes an insulative housing 40 and a metal wire 41 embedded in the insulative housing 40. The two ends (4A, 4B) of the metal wire 41 Exposed to the outside of the insulative housing 40, the electrical connection between the antenna and other components extends, and the appearance of the metal wire 41 assumes a three-dimensional shape.

Please refer to FIG. 5B, which is a perspective view of a second antenna unit according to a fifth embodiment of the present invention. The maximum difference between the fifth embodiment and the first embodiment is shown in FIG. 3 and FIG. 5B. The fifth embodiment discloses a second detailed embodiment of the second antenna unit 4. In the fifth embodiment, the second antenna unit 4 can be a chip antenna, and includes an insulative housing 40 and a metal wire 41 embedded in the insulative housing 40. The two ends (4A, 4B) of the metal wire 41 Exposed to the outside of the insulative housing 40, as an electrical connection between the antenna and other components, the metal wires 41 can be wound on the same plane to form a meandering shape.

Please refer to FIG. 5C, which is a perspective view of the second antenna unit of the sixth embodiment of the present invention directly formed on the upper edge of the circuit substrate. The sixth embodiment and the fifth C diagram show the greatest difference between the sixth embodiment and the first embodiment in that the sixth embodiment discloses a third detailed embodiment of the second antenna unit 4. In the sixth embodiment, the second antenna unit 4 can be a 蜿蜒-shaped metal wire 41 directly formed on the upper edge of the circuit substrate 10 of the substrate unit 1 (that is, at the edge of the upper surface of the circuit substrate 10). That is, the 蜿蜒-type metal wire 41 can be directly formed on the bare region 100 of the circuit substrate 10. For example, the metal wire 41 having a meander shape may be wound on the bare region 100 of the circuit substrate 10 directly by printing, etching or spraying.

Please refer to the sixth figure, which is a perspective exploded view of the first embodiment of the present invention applied to a mobile device. The main difference between the sixth figure and the third figure is that the sixth figure discloses a mobile device M and its outer casing C. The outer casing C can be composed of an upper casing C1 and a lower casing C2, and the first embodiment The FM transmitting antenna is mounted in the mobile device M.

For example, the substrate unit 1 and the second antenna unit 4 are both mounted in the lower casing C2, and the first antenna unit 2 is located above the substrate unit 1 and disposed inside the casing C1 of the mobile device M. On the surface. In addition, the first antenna unit 2 may be a metal plate or a metal film (for example, a conductive copper foil) disposed on the inner surface of the casing C1 above the mobile device M by means of attachment, of course, the first antenna unit 2 may also be a metal layer disposed on the inner surface of the casing C1 above the mobile device M by a direct forming method such as printing or spraying. Therefore, the present invention has the advantages of simple structure, easy fabrication, and low production cost.

In other words, since the area of the first antenna unit 2 can be selectively increased, and can be directly fixed or formed in the inside of the casing C1 above the outer casing C of the mobile device M. The antenna area of the first antenna unit 2 can be similar to that of the substrate unit 1 (system circuit board) or the upper casing C1, which is different from the conventional FM frequency modulation antenna. When the area of the first antenna unit 2 is increased, the present invention can greatly increase the effective radiating area. In addition, because of the large effective radiation area and good radiation characteristics of the built-in FM transmitting antenna, it is very suitable for application in the mobile device M, and can maintain the integrity of the overall appearance of the product, such as the FM transmitting antenna as a FM transmitter for vehicles. use.

The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the invention, and the equivalents of the invention are included in the scope of the invention.

[知知]

1a. . . Tie rod monopole antenna

2a. . . FM dipole antenna with polyethylene

20a. . . Transmission line

22a, 24a. . . Radiation metal wire

[this invention]

1. . . Substrate unit

10. . . Circuit substrate

100. . . Bare area

11. . . Ground plane

12. . . Conductive pad

2. . . First antenna unit

20A. . . Slit

20B. . . Opening

3. . . Conductive unit

3A. . . First end

3B. . . Second end

4. . . Second antenna unit

4A. . . End

4B. . . End

40. . . Insulating body

41. . . metal wires

F. . . FM chip module

M. . . Mobile device

C. . . Outer casing

C1. . . Upper housing

C2. . . Lower housing

The first figure is a schematic diagram of a conventional drawbar type monopole antenna;

The second figure is a schematic diagram of a conventional FM dipole antenna with polyethylene;

The third figure is a three-dimensional combination diagram of the first embodiment of the built-in FM transmitting antenna applied to the mobile device of the present invention.

FIG. 4 is a top view showing the electrical connection between the first antenna unit and the conductive unit according to the second embodiment of the present invention;

FIG. 4B is a schematic top view showing the electrical connection between the first antenna unit and the conductive unit according to the third embodiment of the present invention;

5A is a perspective view of a second antenna unit according to a fourth embodiment of the present invention;

FIG. 5B is a perspective view of a second antenna unit according to a fifth embodiment of the present invention;

FIG. 5C is a perspective view showing the second antenna unit of the sixth embodiment of the present invention directly formed on the upper edge of the circuit substrate;

Figure 6 is a perspective exploded view of a first embodiment of the present invention applied to a mobile device.

1. . . Substrate unit

10. . . Circuit substrate

100. . . Bare area

11. . . Ground plane

12. . . Conductive pad

2. . . First antenna unit

3. . . Conductive unit

3A. . . First end

3B. . . Second end

4. . . Second antenna unit

4A. . . End

4B. . . End

F. . . FM chip module

Claims (10)

A built-in FM transmitting antenna for a mobile device, comprising: a substrate unit having a circuit substrate, at least one ground layer disposed on the circuit substrate, and a plurality of conductive pads disposed on the circuit substrate And a bare region disposed on the circuit substrate, wherein the conductive pads and the exposed regions are not covered by the ground layers; a first antenna unit disposed above the substrate unit and substantially The upper and the substrate unit are parallel to each other; a conductive unit electrically connected between the substrate unit and the first antenna unit; and a second antenna unit directly disposed in the bare area to reduce an antenna Operating frequency, wherein the two ends of the second antenna unit are electrically connected between the two conductive pads, respectively, and the two ends of the second antenna unit respectively pass through the two conductive pads to be respectively electrically Connected to an FM chip module and the conductive unit. The built-in FM transmitting antenna for use in a mobile device according to claim 1, wherein the conductive unit is a flexible element. The built-in FM transmitting antenna applied to the mobile device according to claim 1, wherein the first antenna unit is a metal flat plate or a metal thin film. The built-in FM transmitting antenna for use in a mobile device according to claim 1, wherein the first antenna unit has a slit or an opening adjacent to the conductive unit. Applied to the mobile device as described in claim 1 The FM antenna, wherein the second antenna unit is a chip antenna, and includes an insulative body and a metal wire embedded in the insulating body, the ends of the metal wire are exposed outside the insulating body, and The appearance of the wire presents a three-dimensional surround shape. The built-in FM transmitting antenna for use in a mobile device according to claim 1, wherein the second antenna unit is a chip antenna, and includes an insulative body and a metal embedded in the insulating body. a wire, the two ends of which are exposed to the outside of the insulating body, and the wires are wound on the same plane. The built-in FM transmitting antenna applied to the mobile device according to claim 1, wherein the second antenna unit is a metal wire directly formed on an upper edge of the circuit substrate of the substrate unit. The built-in FM transmitting antenna applied to the mobile device according to the first aspect of the invention, wherein at least one ground layer, the first antenna unit and the second antenna unit of the substrate unit are matched with each other, To form an equivalent circuit similar to a resonator. A built-in FM transmitting antenna for a mobile device, comprising: a substrate unit having a circuit substrate mounted in the mobile device, at least one ground layer disposed on the circuit substrate, and a plurality of a conductive pad on the circuit substrate, and a bare region disposed on the circuit substrate, wherein the conductive pads and the exposed region are not covered by the ground layers; a first antenna unit disposed on Above the substrate unit and attached or formed on an inner surface of the outer casing of the mobile device, wherein the first antenna unit is substantially parallel to the substrate unit; a conductive unit electrically connected between the substrate unit and the first antenna unit; and a second antenna unit disposed directly in the bare area to reduce an antenna operating frequency, wherein the second day The two ends of the wire unit are electrically connected to the two conductive pads, and the two ends of the second antenna unit are respectively electrically connected to the FM chip module and The conductive unit. The built-in FM transmitting antenna applied to the mobile device according to claim 9, wherein at least one ground layer, the first antenna unit and the second antenna unit of the substrate unit are matched with each other, To form an equivalent circuit similar to a resonator.