KR100994583B1 - Active antenna module for low frequency band - Google Patents

Abstract

The active antenna module for the low frequency band of the present invention is formed on at least one surface of a polyhedron block and a polyhedron block on which a first radiator pattern is formed, and is formed at least one spaced apart from the first radiator pattern of the corresponding surface, and is formed as a first radiator pattern. A chip antenna having a coupling pattern coupling the flow of current flowing therein; And a low noise amplifier configured to amplify the received signal received through the chip antenna. The present invention according to the above configuration can be miniaturized and slimmed in the built-in terminal and FM radio reception is possible at a high level of signal strength (RSSI).

 Low frequency, magnetic material, magnetic permeability, radiator pattern, low noise amplification, flexible circuit board

Description

Active antenna module for low frequency band

The present invention relates to an active antenna module for a low frequency band, and more particularly, it is possible to reduce the size and slimness of the terminal due to its excellent space utilization, and to enable the FM radio reception at a high level of signal strength (RSSI). It relates to an antenna module.

With the spread of mobile terminals, it is possible to make and receive calls anytime and anywhere, which has revolutionized the real world. In addition, as more users always carry a mobile communication terminal, various functions are added to help real life. Among the various functions of the mobile communication terminal, the rapid progress is the part related to multimedia, and mobile communication terminals to which functions for generating and playing various multimedia files have been added are pouring out.

That is, the mobile communication terminal is no longer merely a device for voice call, but is treated as a combined integrated portable device having various user convenience functions and entertainment functions. As users watch movies, listen to music, communicate, and make voice calls through a single terminal, the time for carrying and using a mobile communication terminal is gradually increasing.

On the other hand, when a user wants to watch a movie or listen to music using a mobile communication terminal, the user must download and use a movie or music content one by one, and a predetermined additional cost is incurred. On the other hand, in the case of FM radio broadcasting, users do not have to download the contents one by one to enjoy new contents, and since there is no additional cost, users can enjoy the broadcasting contents of new contents without any burden. For this reason, there is a demand for a mobile communication terminal equipped with an FM radio reception function.

However, since the antenna receiving FM has to resonate in the low frequency band of about 87.5 ~ 108MHz, the radiation line of the antenna has to be formed long, and the physical size of the antenna has to be increased. Therefore, in recent years, it has not been easy to implement a miniaturized built-in antenna suitable for a miniaturized and slimmed mobile communication terminal (the antenna's physical size becomes larger as the frequency to be used is low, that is, the wavelength is longer).

In order to overcome the conventional problems described above, there are cases where the size of an antenna is reduced by using a dielectric having a high dielectric constant. However, when implementing a low frequency band built-in antenna using a dielectric having a high dielectric constant, the cost of manufacturing the antenna not only increases, but also causes a problem of narrowing the frequency bandwidth in the low frequency band and thus has desired radiation gain characteristics. The internal antenna for the low frequency band could not be implemented.

In addition, in order to overcome the above-mentioned conventional problems, most users listen to FM radio broadcasts with earphones and use them as an antenna for FM radio reception using earphones. However, in this case, if the earphone (headset, ear microphone) is removed, a fatal problem occurs that the FM radio reception efficiency is extremely low. For example, when outputting an FM radio broadcast to a speaker built in the terminal or when connecting an external speaker to the jack for earphone (the length of the connector functions as an antenna for the FM receiver, but the length is not correct and may interfere with the amplifier and the like) FM reception performance is significantly lowered, making it difficult to listen to normal FM radio. In addition, in the case of a mobile communication terminal having a Bluetooth function, which is widely spread in recent years, since a voice signal output from the terminal is received through a wireless earphone, a method of using the earphone line as an antenna through the earphone jack can be applied. There is no problem. In addition, even in the case of a mobile communication terminal without a Bluetooth function, the earphone must be connected to the terminal in order to receive the FM radio.

Due to the problems as described above, there is a demand for a low frequency band built-in antenna that can be applied to a mobile communication terminal to achieve a miniaturization and slimming of the terminal and to receive FM radio with a high level signal strength (RSSI).

The present invention has been proposed to solve the above-mentioned conventional problems, and can be built in a terminal to achieve miniaturization and slimming of the terminal, and an active type for a low frequency band capable of receiving FM radio at a high level signal strength (RSSI). It is an object to provide an antenna module. In addition, it is an object of the present invention to provide a miniaturized internal antenna device having a high radiation gain in the low frequency band by further forming a radiator pattern to extend the electrical length of the antenna by utilizing the free space inside the terminal frame.

The active antenna module for the low frequency band of the present invention is formed on at least one surface of a polyhedron block and a polyhedron block on which a first radiator pattern is formed, and is formed at least one spaced apart from the first radiator pattern of the corresponding surface, and is formed as a first radiator pattern. A chip antenna having a coupling pattern coupling the flow of current flowing therein; And a low noise amplifier configured to amplify the received signal received through the chip antenna.

In particular, a flexible circuit board is further provided to be connected to the chip antenna, wherein the second radiator pattern is formed on the flexible circuit board, and the second radiator pattern extends to a connection part and a connection part connected to the first radiator pattern, so that the outside of the polyhedral block region It is preferable to have a radiation part formed in the.

Also, the low noise amplifier is preferably formed on the flexible circuit board.

In addition, the low noise amplifier is preferably formed on the other surface opposite to one surface of the flexible circuit board to which the chip antenna is connected.

In addition, the coupling pattern is preferably formed on the lower surface of the polyhedron block in the width direction of the polyhedron block.

In addition, the flexible circuit board further includes a ground pad, and the coupling pattern is preferably electrically connected to the ground pad.

Further, the polyhedral block is preferably a magnetic block having a permeability greater than the permittivity.

In addition, the magnetic block is preferably a magnetic block having a hexahedral shape.

In addition, the first radiator pattern is preferably formed in the form of a winding along the outer surface of the polyhedron block.

In addition, the flexible circuit board further includes a feeding pad, and one end of the first radiator pattern is preferably electrically connected to the feeding pad.

Further, it is preferable that one end of the first radiator pattern is formed on the lower surface of the magnetic block.

The present invention has the following effects.

The active antenna module for the low frequency band according to the present invention can be applied to a mobile communication terminal to achieve miniaturization and slimming of the terminal and to receive FM radio with a high level signal strength (RSSI).

In addition, when the low frequency band active antenna module according to the present invention is mounted on the main printed circuit board, the burden on space is reduced, so that the space utilization can be increased and the degree of freedom for the component installation structure inside the terminal can be improved.

In addition, the active antenna module for the low frequency band according to the present invention does not need any additional means such as earphones for FM radio reception, the configuration is simplified. Accordingly, in the case of a Bluetooth mobile communication terminal, even if a wireless earphone is used, it is possible to maintain a constant reception quality without deteriorating the FM radio broadcast reception rate.

The present invention made as described above will be described in detail with reference to the accompanying drawings. Embodiment of the present invention is provided to those skilled in the art to more fully describe the present invention, the shape and size of the elements in the drawings may be exaggerated for more clear description.

FIG. 1 is a perspective view illustrating an antenna element applied to an active antenna module for a low frequency band according to an embodiment of the present invention, and FIG. 2 illustrates structures of a radiator pattern and a coupling pattern of the antenna element shown in FIG. 1. This is a developed view for the purpose of doing so.

An active antenna module for a low frequency band according to an embodiment of the present invention includes an antenna element 100 and a flexible circuit board 300 (see FIGS. 3 and 4).

The antenna element 100 is a polyhedral magnetic block 110, a couple of the first radiator pattern 120 formed in the form of a winding along the outer surface of the magnetic block 110, the first radiator pattern 120 and a predetermined distance apart The ring pattern 125 is provided.

The magnetic block 110 may be made of a polyhedral magnetic material. Magnetic material (Magneto-dielectric) refers to a material that can be magnetic, and there are iron oxide, chromium oxide, cobalt, ferrite and the like.

Equation 1 is an equation indicating that the bandwidth (BW) of the antenna increases as the ratio between the permeability and the dielectric constant increases when the antenna size does not change. Where λ ₀ is the wavelength, μ _r is the permeability, ε _r is the dielectric constant, and t is the thickness of the antenna. In general, the permeability of the high dielectric constant applied to the antenna is less than the permittivity. However, when a magnetic material having a permeability greater than the permittivity (the magnetic permeability applied in the embodiment of the present invention is about 18 and the permittivity is about 10), a dielectric having a high dielectric constant at the same antenna size is used based on Equation 1. It is possible to implement a wider bandwidth than when. Therefore, when the antenna for the low frequency band is implemented using a high dielectric constant dielectric block for miniaturization, the narrowing of the bandwidth is overcome by using the low dielectric constant and permeability of the magnetic material, thereby minimizing the antenna while maintaining the bandwidth. . On the other hand, since the magnetic block 110 is applied to the present invention has a different permeability and dielectric constant can be selected according to the resonance frequency to implement. In addition, the size and shape of the magnetic block 110 may vary depending on the frequency band to be implemented.

Referring to FIG. 2, the first radiator pattern 120 and the coupling pattern 125 formed on the magnetic block 110 will be described. In order to facilitate understanding of the present invention, the conductor pattern formed on the magnetic block 110 is referred to as a first radiator pattern 120, and the conductor pattern formed on the flexible circuit board 300 to be described later with reference to FIG. 3 is the second radiator pattern 330. This will be called.

The first radiator pattern I ₁ to I _k formed on one side 110a of the magnetic block 110 may include the first radiator I ₁ to I _k formed on the bottom surface 110b of the magnetic block 110. It is connected with the pattern 120, respectively. In Figure 2, one when the first radiator pattern (120) I ₁ ~ I _k formed in a side surface (110a) but that the first radiating pattern (120) I ₁ ~ I _k formed in (110b) are shown as being separate, 2, the first radiator pattern 120 is formed in a winding form along the outer surface of the magnetic block 110 starting from one side of the lower surface 110b of the magnetic block 110. The radiation line of is formed. The length and line width of the first radiator pattern 120 and the distance between the first radiator pattern 120 may vary depending on the resonance frequency to be implemented.

The coupling pattern 125 is formed on the lower surface 110b of the magnetic block 110 independently of the first radiator pattern 120 by a predetermined distance. The coupling pattern 125 couples the flow of current flowing into the first radiator pattern 120 to widen the bandwidth of the antenna. In the embodiment of the present invention, one coupling pattern 125 is formed on the bottom surface 110b of the magnetic block 110 to resonate in the FM radio frequency band (87.5 ~ 108MHz). Only one coupling pattern 125 is illustrated in FIG. 2, but is not limited thereto. The number of coupling patterns 125 causing coupling may vary depending on the frequency band and bandwidth to be implemented, and the resonance frequency and bandwidth to be implemented may be adjusted by increasing or decreasing the number of coupling patterns 125.

3A to 3C are plan views illustrating a structure of a flexible circuit board electrically connected to the antenna element of FIG. 1, and FIG. 4 is a cross-sectional view of FIGS. It is a top view for demonstrating the state mounted on the flexible printed circuit board shown in c).

First, the structure of the flexible circuit board 300 applied to the present invention will be described with reference to FIGS. 3A to 3C.

The antenna element 100 is mounted on any one surface of the flexible circuit board 300 (eg, the upper surface of the flexible circuit board).

The flexible circuit board 300 includes a first conductive pad 310, a second conductive pad 320, a second radiator pattern 330, and a low noise amplifier LNA 340.

A first conductive pad 310 is used as a power supply pad, and side (110b), a first emitter pattern (120; I ₁₎ formed on one end of the magnetic material block 110 is the soldering (Soldering) are electrically connected.

The second conductive pad 320 is used as a ground pad. The second conductive pads 320 are soldered and electrically connected to the coupling pattern 125 formed on the bottom surface 110b of the magnetic block 110.

The second radiator pattern 330 is soldered and electrically connected to the first radiator pattern 120 (I _{k +1} ) formed at the other end of the lower surface 110b of the magnetic block 110. To this end, the second radiator pattern 330 extends to a connection part connected to the first radiator pattern 120 (I _{k +1} ) and to an outside of the region in which the magnetic block 110 is mounted on the flexible circuit board 300. It has a radiating portion formed in. Here, the connection part and the radiating part may be divided based on the bent part 335 illustrated in FIG. 3. That is, the portion of the second radiator pattern 330 that is soldered with the first radiator pattern 120 (I _{k +1} ) based on the bent portion 335 corresponds to the connection portion, and the connection portion extends to the flexible circuit board 400. The portion formed outside the region in which the magnetic block 110 is mounted corresponds to the radiating portion. This also applies to the drawings described below.

When the second radiator pattern 330 is electrically connected to the first radiator pattern 120 (I _{k +1} ) formed at the other end of the bottom surface 110b of the magnetic block 110, the first radiator pattern 120 and the flexible circuit board The second radiator pattern 330 formed at 300 forms one radiation line (see FIG. 4).

The low noise amplifier 340 is provided on the flexible circuit board 300 and electrically connected to the first radiator pattern 120 formed on the magnetic block 110 through the first conductive pad 310. The low noise amplifier 340 amplifies the received signal received through the radiation line to enable FM radio reception at a high level of signal strength (RSSI). The low noise amplifier 340 is designed by grabbing the operating point and the matching point so that the received signal is low NF (noise index).

When the low noise amplifier 340 is provided in the flexible circuit board 300, as shown in FIGS. 3 to 4, the low noise amplifier 340 may be provided in a separate area on the same plane as the antenna element 100 and illustrated in FIG. 5. As described above, the antenna element 100 may be provided on the other surface (the 'A' region of FIG. 5) opposite to one surface on the flexible circuit board 300 on which the antenna element 100 is mounted. In this case, when the low frequency band active antenna module according to the present invention is mounted on the main printed circuit board (not shown), the burden on space can be reduced and the space utilization can be increased, thereby improving the degree of freedom of the component installation structure inside the terminal. You can.

On the other hand, the received signal amplified by the low noise amplifier 340 is generally input to a frequency converter (Tuner, not shown).

The low noise amplifier 340 applied to the present invention is a technical matter that can be easily implemented by those skilled in the art using a known technique, and thus, further detailed description thereof will be omitted.

According to the present invention, the first radiator pattern 120 formed in the magnetic block 110 having a permeability greater than that of the dielectric allows a wider bandwidth than when using a dielectric having a high dielectric constant at the same antenna size. Due to the second radiator pattern 330 formed on the flexible circuit board 300 which is electrically connected to the radiator pattern 120 to form a long radiation line, the resonance frequency of the antenna can be lowered. In addition, the resonance caused by the current supplied to the first radiator pattern 120 and the second radiator pattern 330 through the first conductive pad 310, and the coupling pattern 125 and the first radiator pattern 120. And due to the interaction of the resonance caused by the second radiator pattern 330 it is possible to improve the radiation characteristics.

On the other hand, the radiation characteristics and the resonant frequency of radio waves emitted by the second radiator pattern 330 are changed by the length or width of the second radiator pattern 330, the slots engraved in the second radiator pattern 330. That is, the antenna radiation characteristic and the resonance frequency may be changed by tuning the second radiator pattern 330. Therefore, when the antenna according to the embodiment of the present invention is mounted in the terminal, only the second radiator pattern 330 may be adjusted to implement a desired radiation characteristic and a resonance frequency. In addition, as described above, the second radiator pattern 330 is formed on the flexible circuit board 300, so that the portion of the flexible circuit board 300 on which the second radiator pattern 330 is formed may be bent in the terminal 335. Therefore, it is possible to bend freely. This makes it possible to increase the degree of freedom in the arrangement of components and the degree of integration of components in the design of the terminal, thereby miniaturizing and slimming the terminal. On the other hand, the bent portion 335 is not limited to the portion shown in the drawings, it is possible to change depending on the shape and structure of the flexible circuit board 300. In addition, the shape and structure of the flexible circuit board 300 may also be changed according to the free space inside the terminal.

6 is a perspective view illustrating a shape in which an active antenna module for a low frequency band according to an embodiment of the present invention is mounted on a main printed circuit board of a terminal.

Referring to FIG. 6, an active antenna module 500 for a low frequency band according to an embodiment of the present invention is mounted on a main printed circuit board 400 of a terminal. More specifically, the portion of the flexible circuit board 300 on which the antenna element 100 is mounted is mounted on the main printed circuit board 400 and the second radiator pattern 330 of the flexible circuit board 300 is mounted. The formed portion is located in the free space inside the terminal. For example, when the active antenna module 500 for low frequency band according to an embodiment of the present invention is mounted on the main printed circuit board 400 of the terminal, the second radiator pattern 330 formed on the flexible printed circuit board 300 may be formed. The bent portion 335 is bent and mounted to be perpendicular to the main surface of the main printed circuit board 400. At this time, by providing a separation distance between the second radiator pattern 330 and the main printed circuit board 400, it is possible to mitigate interference from the main printed circuit board 400 with respect to the radiation characteristics of the antenna. That is, since the second radiator pattern 330 is installed inside the terminal at a predetermined distance apart from the main printed circuit board 400 of the terminal, the second radiator pattern 330 receives less interference from the circuit terminal of the main printed circuit board 400, thereby causing the antenna The radiation characteristic of is improved. For reference, the built-in antenna for FM radio reception is very sensitive to ambient noise, so the radiation characteristic depends a lot on the ambient noise. Preferably, a shielding film may be formed between the main printed circuit board 400 and the second radiator pattern 330 to more reliably block interference from the circuit ends of the main printed circuit board 400.

As described above, when the low frequency band built-in antenna module 500 according to the present invention is mounted on the main printed circuit board 400, physical deformation may not be applied to the antenna element 100, and the second radiator pattern may be used. Physical deformation may be applied only to the flexible circuit board 300 on which the 330 is formed. That is, since the physical deformation does not occur with respect to the feed line and the ground line formed in the antenna element 100, an embedded antenna having stable radiation characteristics is implemented. In addition, since the second radiator pattern 330 is formed on the flexible circuit board 300, it is easy to mount the second radiator pattern 330 so as to be located in a free space inside the mobile communication terminal. To increase the

7 is a diagram illustrating received signal strength (RSSI) for each frequency band of a built-in antenna for a low frequency band according to an embodiment of the present invention.

FIG. 7 illustrates a case in which a low frequency band built-in antenna module according to an embodiment of the present invention is used to receive an FM radio frequency band ('AMFA + LNA' of FIG. 7), and the low noise amplifier 340 is not provided. Received Signal Strength Indication (RSSI) between the case of using a low frequency band built-in antenna module ('AMFA' in FIG. 7) and an earphone antenna ('Earset' in FIG. 7). It will be described by comparing. Here, the source of the antenna element 100 applied to the low-frequency internal antenna module according to an embodiment of the present invention is a magnetic block having a size of 12 * 5 * 2 and a magnetic permeability of 18.

In the low frequency band (87.5MHz ~ 108MHz) when using the low-frequency built-in antenna module according to an embodiment of the present invention ('AMFA + LNA' of Figure 7) low frequency band without the low noise amplifier 340 About 20 dB more on average than the built-in antenna module for use ('AMFA' in Figure 7) You can see the FM radio signal is received at the signal strength of the level.

Furthermore, it can be seen that the FM radio signal is received at a higher level of signal intensity than in the case of using the earphone antenna conventionally applied ('Earset' of FIG. 7). In the case of the earphone antenna, which has been conventionally applied, the reception signal strength is generally good in the low frequency band. However, as mentioned in the background art, when the earphone is separated from the terminal, the FM radio reception efficiency is extremely low.

That is, according to the present invention, a low frequency band (87.5MHz ~ 108MHz) that can receive the FM radio, the desired signal strength is shown, and a low frequency band built-in antenna for impedance matching while satisfying a wide bandwidth in the low frequency band is implemented. In addition, the antenna efficiency and radiation characteristics can be maintained and can be miniaturized, which can be applied to a mobile communication terminal.

On the other hand, the low-frequency band built-in antenna according to the present invention is not limited to the mobile communication terminal can be applied, but may also be applied to a small sound device, a terminal, and an antenna device for receiving low frequency.

As mentioned above, although one preferred embodiment of the present invention has been illustrated and described, the present invention is not limited to the specific embodiments described above, and the present invention belongs to the present invention without departing from the gist of the present invention as claimed in the claims. Of course, various modifications can be made by those skilled in the art.

1 is a perspective view illustrating an antenna element applied to an active antenna module for a low frequency band according to an embodiment of the present invention.

FIG. 2 is an exploded view for explaining the structure of a radiator pattern and a coupling pattern of the antenna element shown in FIG. 1.

3A to 3C are plan views illustrating the structure of a flexible circuit board connected to the antenna element of FIG. 1.

4 is a plan view illustrating a state in which the antenna element of FIG. 1 is mounted on the flexible circuit board illustrated in FIGS. 3A to 3C.

5 is a view for explaining an area on a flexible circuit board on which a low noise amplifier is formed.

6 is a perspective view illustrating a shape in which an active antenna module for a low frequency band according to an embodiment of the present invention is mounted on a main printed circuit board of a terminal.

7 is a diagram illustrating received signal strength (RSSI) for each frequency band of a built-in antenna for a low frequency band according to an embodiment of the present invention.

Claims (11)

A polyhedron block on which a first radiator pattern is formed, and a surface formed on at least one surface of the polyhedron block, at least one formed spaced apart from the first radiator pattern on the surface, and coupling a flow of current flowing into the first radiator pattern A chip antenna having a coupling pattern to ring; A low noise amplifier for amplifying a received signal received through the chip antenna; And A connection part connected to the first radiator pattern of the chip antenna and disposed inside the printed circuit board area of the terminal, and extended to the connection part to be parallel to the chip antenna outside the chip antenna area and to an empty space inside the terminal. An active antenna module for a low frequency band including a flexible printed circuit board having a second radiator pattern having a radiating portion disposed in the. delete The method according to claim 1, The low noise amplifying unit is an active antenna module for a low frequency band, characterized in that formed on the flexible circuit board. The method according to claim 3, The low noise amplifier, The active antenna module for low frequency band, characterized in that the chip antenna is formed on the other surface opposite to one surface of the flexible circuit board connected. The method according to claim 1, And said coupling pattern is formed on the lower surface of said polyhedron block in the width direction of said polyhedron block. The method according to claim 1, The flexible circuit board further includes a ground pad, And the coupling pattern is electrically connected to the ground pad. The method according to claim 1, The polyhedron block is a low-frequency active band antenna module, characterized in that the magnetic permeability is greater than the permittivity block. The method of claim 7, The magnetic block is a low-frequency active band antenna module, characterized in that the magnetic block having a hexahedral shape. The method according to claim 1, The first radiator pattern is an active antenna module for a low frequency band, characterized in that formed in the form of a winding along the outer surface of the polyhedral block. The method according to claim 1, The flexible circuit board further includes a feeding pad, An active antenna module for a low frequency band, characterized in that one end of the first radiator pattern is electrically connected to the feed pad. The method according to claim 10, One end of the first radiator pattern is formed on the lower surface of the polyhedral block active antenna module for low frequency band.

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