KR20160101640A - Antenna Bandwidth Expander - Google Patents

Abstract

Disclosed is a bandwidth expander for expanding the bandwidth of an antenna in which wide broadband frequency characteristics including various communication bands are necessary like an LTE smartphone, thereby improving the transmission and reception performance of a wireless communications device. An antenna bandwidth expander at low costs expands the bandwidth of the antenna in a first resonant frequency band and a second resonant frequency band easily and conveniently, thereby securing the performance of a transmission and reception terminal.

Description

Antenna Bandwidth Expander

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna bandwidth extension device installed between an antenna and an internal RF circuit, and relates to a technique for improving transmission / reception performance of a communication terminal by applying it to a broadband communication system having a wider frequency band.

Recently, as various communication services such as LTE mobile communication terminal and object internet are commercialized, the frequency band to be supported by one terminal is gradually increasing, and the size of the antenna is gradually decreasing due to slim design of product and application of high capacity battery .

In this situation, researches on antenna development that can realize multi - band and wideband antenna with small antenna size are performed in various aspects of designing method and manufacturing method, but they can not overcome limitations due to antenna size limitation. Particularly, in case of LTE (Long Term Evolution) communication terminal, application to frequency band switching using a tunable antenna module or an RF switch is overcome to overcome the difficulty of implementation of a broadband antenna characteristic. However, Of the complexity of the.

For example, FIG. 1 (a) shows a case where the traveling wave in the antenna direction and the reflected wave from the antenna are respectively detected by power detection and the relative reflection is kept below a certain reference value (VSWR reference management) The DAC value is adjusted to control the LC value inside the TAM to tune the antenna matching in real time.

1 (b) shows a structure for controlling the position of the antenna ground feeding to switch to a desired frequency. SW1 and SW2 denote switches, and M1 and M2 denote matching circuits.

A resonance frequency shift due to the change of the resonance length of the antenna when SW1 is connected and when SW2 is connected is used.

According to the prior art shown in FIG. 1 (a), a software algorithm for performance optimization is complicated, and manufacturing costs are increased due to the application of expensive TAM, and a complicated control unit circuit is required to control the manufacturing cost. . Also, in order to widen the tuning range, L and C values with large losses are applied and the loss due to the lumped element becomes large. And the external DC power supply may cause noise problems to the antenna.

According to the prior art shown in FIG. 1 (b), the degree of shifting the frequency varies according to the proper spacing distance d of the grounding feed. However, if the distance deviates from the signal feeding pin by more than a certain distance, the antenna matching characteristic in a specific frequency band is deteriorated. Therefore, when a large shift amount of frequency is required, there is a problem that the characteristics of a frequency band that is not selected by switching on / off deteriorates. Also, since the antenna pattern and the DC power supply are electrically connected to each other, the sensitivity of the antenna is deteriorated due to the influence of the antenna noise caused by the power supply.

Therefore, it is an object of the present invention to provide an antenna bandwidth extension device which can improve transmission and reception performance of a communication terminal by applying to a broadband communication system in which a frequency band is gradually widened, .

It is another object of the present invention to provide an antenna bandwidth expanding device which is simple in structure, low in manufacturing cost, and does not occupy a large mounting area in an electronic device.

The above object is achieved by a radio communication system comprising: a first conductive terminal mounted on a circuit board to be electrically connected between an RF system and an antenna, the first conductive terminal being electrically connected to the antenna; A second conductive terminal electrically connected to the first conductive terminal via a first capacitor; A first coil electrically connected between the first and second conductive terminals; A third conductive terminal electrically connected to the feeding portion of the RF system; A fourth conductive terminal electrically connected to the third conductive terminal via a second capacitor; A second coil electrically connected between the third and fourth conductive terminals; And third and fourth capacitors interposed between the second and third conductive terminals and the first and fourth conductive terminals, wherein the second capacitor and the fourth capacitor are connected in parallel and in parallel to the second coil, respectively, Wherein the first and third capacitors constitute a second frequency band resonant circuit which is connected in parallel and in series to the first coil so as to be a high frequency band, And the first and third capacitors are connected in parallel to the first coil to constitute a second frequency band resonant circuit which is a high frequency band and the first and second coils are wound in opposite directions to be magnetically coupled ≪ / RTI >

It is an object of the present invention to provide an RF system and an antenna, which are mounted on a circuit board so as to be electrically connected to the RF system and the antenna, wherein the first to fourth conductive terminals are spaced apart from each other, And a second coil electrically connected between the third and fourth conductive terminals; And first to fourth capacitors interposed between the first to fourth conductive pads formed corresponding to the first to fourth conductive terminals on the circuit board, wherein the first conductive terminal is electrically connected to the antenna And the third conductive terminal is electrically connected to the feeding part of the RF system so that the second and fourth capacitors are connected in parallel and in series to the second coil to constitute a first frequency band resonant circuit which is a low frequency band And the first and third capacitors are connected in parallel and in series to the first coil to constitute a second frequency band resonant circuit which is a high frequency band, and the first and second coils are wound in opposite directions to magnetically couple The antenna bandwidth extension device comprising:

Preferably, the first coil may be located inside the second coil.

Preferably, the horizontal cross-sectional shape of the first and second coils may be circular or polygonal.

Preferably, the second and fourth conductive terminals may be electrically connected to the ground via an external inductor.

The above object is achieved by a ceramic sheet comprising: a first ceramic sheet having conductive terminals formed on four corners of a lower surface thereof and having a ground terminal at a center thereof; A second ceramic sheet on which a first capacitor pattern is formed; A plurality of third ceramic sheets on which the first capacitor pattern or the second capacitor pattern and the first and second coil patterns are formed; And a fourth ceramic sheet on which the first capacitor pattern is formed. The ceramic sheets are sequentially laminated so that the first and second coil patterns are connected to each other through the via holes to form coils, Wherein the first and second capacitor patterns are stacked on each other to constitute a capacitor, and the coil and the capacitor are electrically connected to the conductive terminal through a via hole. do.

Preferably, the first ceramic sheet is provided with conductive terminals at four corners of the lower surface thereof and a ground terminal at the center thereof. A second ceramic sheet having one connection pattern; A plurality of third ceramic sheets on which first and second coil patterns are formed; Wherein the first and second coil patterns are connected to each other via via holes to form a coil and are magnetically coupled to each other, And electrically connected to the conductive terminal via the connection pattern and the via hole.

Preferably, the first and second coil patterns may be formed on different ceramic sheets.

According to the above configuration, the bandwidth of the antenna that requires wide frequency characteristics can be extended.

In addition, since the structure is simple, the manufacturing cost is low, and the mounting area is not occupied much in an electronic device such as a smart phone.

Also, it can be used alone or as a matching circuit at the rear end of the antenna, and can be applied to the front end or the rear end of the matching circuit, thereby increasing the degree of freedom in system design.

Figure 1 shows the prior art.
FIG. 2 shows a bandwidth extension device and a layered structure according to an embodiment of the present invention.
FIG. 3 shows an internal connection structure of a bandwidth extension device according to an embodiment of the present invention. FIG. 3 (a) shows a structure that is coupled between coil patterns affecting a low frequency band and a high frequency band, (b) shows the isolated structure of the coil pattern affecting the low and high frequency bands.
4 is an interior plan view of a bandwidth extension device in accordance with an embodiment of the present invention.
5 is an equivalent circuit diagram of a bandwidth extending apparatus according to an embodiment of the present invention.
6 (a) and 6 (b) show the magnetic field distribution at the first resonance frequency (925 MHz) and the second resonance frequency (1990 MHz).
7 (a) and 7 (b) are graphs showing the effect of return loss on the sizes of the coils 1 and 2, respectively.
8 (a) and 8 (b) are graphs showing the effect of return loss on the external inductors L ₃ and L ₄ .
9 is a graph showing return loss characteristics measured through inductance values of external inductors L ₃ and L ₄ .
10 (a) is a graph showing return loss values measured by optimizing the coil size, and FIG. 10 (b) is a graph showing frequency characteristics with respect to insertion loss in the first resonance frequency band and the second resonance frequency band.
11 is a graph showing a comparison between S11 [dB] of an antenna to which an antenna bandwidth expanding apparatus of the present invention is applied, and reflection loss of an LC-matched antenna in a specific product.
FIG. 12A is a graph showing radiation efficiency in a first resonance frequency band, and FIG. 12B is a graph showing radiation efficiency in a second resonance frequency band.
13 shows a bandwidth extension device according to another embodiment of the present invention.
14 is a wiring diagram of a bandwidth extension device according to another embodiment of the present invention.
15 is an internal plan view of a bandwidth extension device according to another embodiment of the present invention.

Hereinafter, an antenna bandwidth expanding apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

3 shows an internal connection structure of a bandwidth expanding apparatus according to an embodiment of the present invention. FIG. 3 (a) shows a structure of a bandwidth expanding apparatus and a layer structure according to an embodiment of the present invention, And FIG. 3 (b) shows the separated structure of the coil pattern affecting the low frequency band and the high frequency band. FIG. 4 Lt; RTI ID = 0.0 > of < / RTI > In FIG. 3 (b), the same reference numerals are omitted for the same conductive pattern.

The antenna bandwidth expanding device comprises a box-shaped ceramic body 10 and conductive terminals 21, 22, 23 and 24 exposed at the lower surface and a ground terminal 25. The ceramic body 10 has a conductive pattern Ceramic sheets 11, 12, 13, 14, 15, 16 are laminated. Here, the ground terminal 25 may be a dummy terminal for increasing the soldering strength, and if omitted, there is no significant influence on the characteristics. When the ground terminal 25 is omitted, the conductive terminals 21, 22, 23, and 24 exposed on the lower surface extend to the side surface of the ceramic body.

The antenna bandwidth extension device can be surface mounted by vacuum pick-up, for example mounted on a circuit board mounted inside a mobile phone, which is an independent component, for example between the feed port of the RF system and the connection port connected to the antenna, And is electrically connected.

In the ceramic body 10, conductive patterns printed on the respective ceramic sheets (or green sheets) 11, 12, 13, 14, 15, 16 are electrically or magnetically connected in a three- Circuit.

In other words, each conductive pattern (i.e., coil pattern, capacitor pattern, connection pattern, and the like) is formed on each of the ceramic sheets 11 to 16 constituting six layers in each layer, (Ag) paste is printed and formed, and the ceramic body 10 is formed by laminating the layers and firing using the LTCC method.

22, 23, and 24 are formed at four corners on the lower surface of the ceramic sheet 11 and a ground terminal 25 is formed at the center. The conductive terminals 21, 22, 23, Holes 101, 104, 201, and 204 are formed in the ceramic sheet 11 at the position shown in Fig.

Here, the via holes formed at the same position in each ceramic sheet are given the same reference numerals.

Capacitor patterns 112, 121, 212 and 221 and connection patterns 241, 242, 243 and 244 are formed on the upper surface of the ceramic sheet 12 and electrically connected to the conductive terminals 21, 22, 23, 24, and 24 are formed in the via holes 101, 104, 201, and 204, respectively.

Capacitor patterns 111, 122, 211 and 222 and coil patterns 131 and 231 are formed in the ceramic sheet 13 and capacitor patterns 112, 121, 212 and 221 and coil patterns 122 and 211 and 212 and coil patterns 133 and 233 are formed on the ceramic sheet 15 and capacitor patterns 112 and 121 and 232 are formed on the ceramic sheet 16. The capacitor patterns 111, 212 and 221 and connection patterns 245 and 246 are formed.

As shown in FIG. 2 (b), via holes for electrical connection between the upper and lower portions are formed in the respective ceramic sheets 13, 14, 15 and 16, and the via holes for direct electrical connection with the conductive terminals 21, 22, 23 and 24 Holes (not labeled) for electrically connecting the via holes 101, 104, 201 and 204, the coil patterns 131, 132 and 133 (231, 232 and 233) 103, 105, and 106 for electrical connection between the conductive terminals 21, 22, 23, and 24, and the conductive terminals 21 and 22, ) 202, 203 (205, 206) are formed at appropriate positions of the respective ceramic sheets 13, 14, 15, 16.

3 (b), the conductive terminals 21, 22, 23, and 24 are electrically connected to the conductive plugs 101 ', 104', 201 ', and 204 filled in the via holes 101, And the conductive plugs 102 ', 103', 105 ', 106', 202 ', 203' filled in the via holes 102, 103, 105, 106, And the conductive patterns 213 are connected to the capacitor patterns 111 and 112 (121 and 122) 211 and 212 (221 and 222) through the conductive patterns 205 'and 206' Are connected to the coil patterns 130 and 230 through the plugs 103 ', 106', 203 ', and 206', respectively.

Therefore, the capacitor patterns 111, 112 (121, 122) 211, 212 (221, 222) constitute a capacitor as a whole and the coil patterns 131, 132, 133 (231, 232, 233) The combined coil 1 (130) and coil 2 (230) are formed, and a circuit description related thereto will be described later.

In this embodiment, the coil patterns 131, 132, 133 constituting the coil 1 130 and the coil patterns 231, 232, 233 constituting the coil 2 230 are all formed on the same ceramic sheets 13, It is needless to say that they can be formed on different ceramic sheets as required.

Hereinafter, the configuration and operation of the bandwidth expanding apparatus according to an embodiment of the present invention will be described in detail.

5 is an equivalent circuit diagram of a bandwidth extending apparatus according to an embodiment of the present invention.

3, the conductive terminal 21 is electrically connected to a connection port connected to the antenna, and the conductive terminal 23 is connected to the power supply part (not shown) of the RF system feed port.

Therefore, the signal energy transmitted from the RF system through the conductive terminal 23 is transmitted to the coil 2 230, and an induced current is induced in the coil 1 130 due to the flux component of the magnetic field generated by the coil 2 230 And is transmitted to the conductive terminal 21 and to the connection port of the antenna.

Coil 1 130 is formed in a direction opposite to the winding direction of coil 2 230 to induce magnetic field coupling. The first resonance frequency band which is a low frequency band due to the winding directions of the first coil 130 and the second coil 230 can induce a strong magnetic field coupling in the region between the first coil 130 and the second coil 230, The second resonant frequency band, which is a high frequency band, allows signal energy to be transmitted through a strong magnetic field coupling in the central region of the coil 1 130 and the coil 2 230.

In this embodiment in which the coil 2 230 includes the coil 1 130, although the coil 1 130 and the coil 2 230 form coils in opposite directions to each other, the coil 1 130 and the coil 2 (230) may be formed to have the same winding direction to form a magnetic field coupling at the center of the coil.

The capacitor patterns 111 and 221 (112 and 122) 121 and 211 and 212 and 222 each have a laminated structure to constitute the capacitors C ₁₄ , C ₁₂ , C ₃₂ and C ₃₄ of FIG. 4, The coil patterns 131, 132 and 133 (231, 232 and 233) formed on the sheets 13, 14 and 15 are laminated to constitute the coil 1 130 and the coil 2 230.

Accordingly, the capacitors C ₁₂ and C ₁₄ , C ₃₂ and C ₃₄ are connected in parallel to the coils 1 and 2 (130 and 230), respectively, and load capacitance values between the respective conductive terminals 21, 22, 23 and 24.

Although the coils 1,2 and 130 are not electrically connected to each other, they are induced by the magnetic flux of the magnetic field generated by the coil 230, The current is coupled so that the signal energy at the feed section of the RF system is transmitted to the connection port of the antenna.

The coil patterns 131, 132, and 133 (231, 232, and 233) formed on the ceramic sheets 13, 14, and 15 respectively include a portion of the coils 1, And the coils 1,2 and 130 and 230 are formed in different sizes so that one coil is located inside the other coil. Here, the structure in which the coil 1 (130) is completely included in the coil 2 (230) is a structure in which the coupling between the coils is maximized and the loss of signal energy can be minimized.

Coil second series connected capacitors to 230 C _14, parallel-connected C ₁₂ is combined with the coil 2 (230) and form a LC resonance circuit, connected in series to the coil 1 (130) capacitors C _12, parallel The connected C ₃₂ combines with coil 1 130 to form another LC resonant circuit.

Referring to FIG. 5, the bandwidth extension device is divided into a first resonant frequency block 100 that affects a low frequency band and a second resonant frequency block 200 that affects a high frequency band.

Therefore, the elements that have a major influence on the first resonant frequency are the coil 2 230, the capacitors C ₁₄ and C _34, and the external inductor L _4, and the elements that have a major influence on the second resonant frequency are the coil 1 130 and the capacitor C ₁₂ , C _32, and an external inductor L ₃ . The mutual inductance L _M formed by the coils 1 and 2 (130, 230) affects the first resonant frequency and the second resonant frequency at the same time.

In summary, the coil 2 230, the capacitors C ₁₄ and C _34, and the external inductor L ₄ form a first resonance frequency block 100 that affects the low frequency band, and the coil 1 130 and the capacitors C ₁₂ and C ₃₂ and the external inductor L ₃ form a second resonant frequency block 200 that affects the high frequency band.

Here, the conductive terminals 22,24 are respectively electrically connected to the ground via the external inductor L ₃ and L _4.

The magnetic coupling of the coils 1,2 and 130 and 230 must be strongly formed in order to efficiently transfer signal energy from the conductive terminal 23 connected to the feeding part of the RF system to the conductive terminal 21 connected to the connection port of the antenna.

To illustrate the coupling between coils, we usually use coupling coefficient k, where k has a value between 0 and 1, 0 means decoupling between coils, 1 means ideal between coils, Which means that there is coupling. Generally, the shape, spacing, and direction of the coil affect the k value.

The antenna bandwidth extension device of the present invention is a structure in which the coil 2 (230) completely includes the coil 1 (130) and is magnetically coupled by being wound in the opposite direction to each other. The first frequency band minimizes the separation distance between the coils, And the second resonance frequency band is a structure that enables signal energy transmission over a wide band while minimizing loss by strengthening magnetic field coupling at the center of the coil.

6 (a) and 6 (b) show the magnetic field distribution at the first resonance frequency (925 MHz) and the second resonance frequency (1990 MHz). At the first resonance frequency, the magnetic field is strongly formed in the region between the coils 1 and 230 and at the second resonance frequency, the magnetic field is strongly formed in the region inside the coil 130.

7 (a) is a graph showing the effect of return loss on the size of coil 1 130. FIG. It can be seen that as the size of the coil 1 increases, the first resonance frequency does not change much but the second resonance frequency moves toward the lower side.

7 (b) is a graph showing the influence of the return loss on the size of the coil 2. Fig. It can be seen that as the size of the coil 2 increases, the first resonance frequency moves toward the lower side and the second resonance frequency does not change much.

8A shows the effect of return loss on the external inductor L _{3. As the} L ₃ inductance value becomes lower, the second resonant frequency shifts toward higher, and the impedance matching at the second resonant frequency through the appropriate value is optimized .

FIG. 8 (b) shows the effect of the return loss on the external inductor L _{4. As the} L ₃ inductance value decreases, the first resonance frequency shifts to higher value and the impedance matching at the first resonance frequency through the appropriate value is optimized .

FIG. 9 is a graph showing the relationship between capacitances of the capacitors C ₁₄ , C ₁₂ , C ₃₂ and C ₃₄ connected in series and in parallel to each coil when the horizontal cross-sectional shapes of the coils 1 and 2 have a size of 0.5 × 0.5 mm and 1.0 × 1.0 mm, The effects on the capacitance values are measured and the return loss characteristics measured through the inductance values of the appropriate external inductors L ₃ and L ₄ .

The following [Tables 1] and [2] are the coil size of the sample S applied to the measurement result of FIG. 9 and the inductance values of the external inductors L ₃ and L ₄ , and [Table 3] The capacitance value of the capacitor is summarized.

Size (mm) inductance Coil 1 0.5 x 0.5 5.5 nH Coil 2 1.0 x 1.0 16.0 nH

L ₃ , L ₄ matching value Sample Type L ₃ L ₄ S1 12nH 47nH S2 15nH 68nH S3 18nH 82nH

Size (mm) Capacitance
S1

C ₃₄ 0.4 x 0.2 0.8 ㎊ C ₁₄ 0.4 x 0.2 0.8 ㎊ C ₁₂ 0.2 x 0.2 0.4㎊ C ₃₂ 0.2 x 0.2 0.4㎊
S2
C ₃₄ 0.6 x 0.2 1.0 ㎊ C ₁₄ 0.6 x 0.2 1.0 ㎊ C ₁₂ 0.3 x 0.2 0.4㎊ C ₃₂ 0.3 x 0.2 0.4㎊
S3 C ₃₄ 0.8 x 0.2 1.2 ㎊ C ₁₄ 0.8 x 0.2 1.2 ㎊ C ₁₂ 0.4 x 0.2 0.6㎊ C ₃₂ 0.4 x 0.2 0.6㎊

Fig. 10 (a) shows that the first resonance frequency and the second resonance frequency are optimized for a specific product with the return loss value measured by optimizing the coil size, Fig. 10 (b) And shows the frequency characteristic for insertion loss in the resonance frequency band.

11 is a graph comparing the return loss of an antenna that has undergone LC matching in a specific product with that of an FR4 bare PCB having a PCB size of 130 x 65 x 0.8 mm by comparing the return loss of an antenna applied with the antenna bandwidth extension device of the present invention [Table 4] summarizes the bandwidth improvement effect of the antenna when only the antenna including the LC matching circuit and the bandwidth extension device are added.

Antenna bandwidth comparison
(VSWR = 4.0) Low frequency band High frequency band Antenna alone
(22nH shunt) 765-864
(BW = 99 MHz) 1711-2017
(BW = 306 MHz) Antenna + Expansion Unit
(L3 = 10nH, L4 = 22nH) 722-920
(BW = 198 MHz) 1608-2115
(BW = 507 MHz) Bandwidth (BW) expansion effect 100% 65% Sample substrate size 130 x 65 x 0.8 mm

Referring to Table 4, the bandwidth of the antenna including the bandwidth extension device has a bandwidth improvement of 100% in the first resonance frequency band with a VSWR of 4.0 based on the bandwidth of the antenna designed only by the LC matching circuit, There is a 65% bandwidth improvement in frequency.

12 (a) is a graph showing radiation efficiency in a first resonance frequency band, which is a comparative measurement of radiation efficiency in the case where a bandwidth expanding device limited by the present invention is provided and only an LC matching circuit is provided.

As can be seen from the graph, the peak emission efficiency at the resonance frequency is lower than that when only the LC matching circuit is applied when the bandwidth extension device is included (indicated by the solid line). However, at frequencies near the both end boundaries, mismatching loss is reduced to increase the radiation efficiency and to obtain a flat radiation efficiency characteristic as a whole.

12 (b) shows the radiation efficiency in the second resonance frequency band, which is a graph comparing the radiation efficiency in the case where the bandwidth extending device is provided and in the case where only the LC matching circuit is provided. As shown in FIG. 12 (a), mismatching loss due to the bandwidth expansion effect is reduced at the frequency near the boundary between the two ends when the bandwidth matching device is included (indicated by a solid line) And the uniformity of radiation efficiency can be obtained as a whole.

As described above, the bandwidth extension device according to the present invention is applied between an internal RF system and an antenna having an arbitrary impedance characteristic. It is applied to the front end or the rear end of the matching circuit to enlarge the bandwidth of the antenna, It can be applied directly to the rear end to broaden the bandwidth at the same time as matching the antenna impedance.

In the above embodiment, the horizontal cross-sectional shape of the coils 1 and 2 is set to be a rectangle, but the present invention is not limited thereto.

FIG. 13 is a diagram illustrating a bandwidth expanding apparatus according to another embodiment of the present invention, FIG. 14 is a connection diagram of a bandwidth expanding apparatus according to another embodiment of the present invention, FIG. 15 is a block diagram of a bandwidth expanding apparatus according to another embodiment of the present invention, It is an internal plan view.

The antenna bandwidth extension device of this embodiment has coil patterns 130 and 230 and connection patterns 241, 243, 245, and 246 without a capacitor pattern therein, as compared with the antenna bandwidth extension device of the above embodiment .

13, conductive terminals 21, 22, 23, and 24 are formed on four lower corners of the ceramic body 10. In order to improve the soldering strength, conductive terminals 21, 22, 23, and 24 are formed along the side walls of the ceramic body 10. [ The terminals 21, 22, 23 and 24 can be extended.

As shown in Fig. 15, a dummy terminal for forming the ground terminal 25 or for improving the soldering strength may be formed at the center of the lower surface, or nothing may be formed.

The ceramic body 10 can be formed by laminating the ceramic sheets 11 to 16 and firing them using the LTCC method, as shown in Fig.

22, 23, and 24 are formed at four corners on the lower surface of the ceramic sheet 11 and a ground terminal 25 is formed at the center. The conductive terminals 21, 22, 23, Holes 101, 104, 201, and 204 are formed in the ceramic sheet 11 at the position shown in Fig.

Connection patterns 241 and 243 are formed on the upper surface of the ceramic sheet 12 and via holes 104 and 204 for electrically connecting the conductive patterns to the conductive terminals 21, 22, 23 and 24 of the ceramic sheet 11 are formed do.

Coil patterns 131, 132 and 133 (231, 232 and 233) are formed in the ceramic sheets 13, 14 and 15, via holes 104 and 204 are formed, Patterns 245 and 246 and via holes 104 and 204 are formed.

Therefore, the coil patterns 131, 132, and 133 (231, 232, and 233) as a whole form a magnetic field-coupled coil 1 130 and a coil 2 230.

The conductive terminal 21 is electrically connected to the connection port connected to the antenna, and the conductive terminal 23 is electrically connected to the connection terminal connected to the antenna. In this case, And is electrically connected to the feed port of the RF system.

Therefore, the signal energy transmitted from the RF system through the conductive terminal 23 is transmitted to the coil 2 230, and an induced current is induced in the coil 1 130 due to the flux component of the magnetic field generated by the coil 2 230 And is transmitted to the conductive terminal 21 and to the connection port of the antenna.

14, a ceramic body 10 is mounted on a circuit board. A conductive pad corresponding to the conductive terminals 21, 22, 23, 24 is formed on the circuit board. Capacitors C ₁₄ , C ₁₂ , C _32, and C ₃₄ are mounted.

Therefore, while the ceramic body 10 of the antenna bandwidth expander is mounted on the circuit board, the capacitors C ₁₄ , C ₁₂ , C ₃₂ and C ₃₄ are connected in parallel with the coils 1 and 2, and the respective conductive terminals 21, 22, 23, 24, respectively.

The like as in the above example, the coil 2 (230) connected in series to a capacitor C _14, connected in parallel to the C ₁₂ is a coil 2, 230 form a LC resonant circuit in conjunction with, the coil 1 (130) to The series-connected capacitors C ₁₂ , C ₃₂ connected in parallel combine with coil 1 130 to form another LC resonant circuit.

Similarly, although the coils 1 and 2 (130 and 230) are not electrically connected, an induced current is coupled to the coil 1 (130) by the flux component of the magnetic field generated by the coil 2 (230) The signal energy at all is transmitted to the connection port of the antenna.

According to this embodiment, since the capacitor is not required to be implemented in the ceramic body of the antenna bandwidth expander, the structure is simple and the capacity of the capacitors C ₁₄ , C ₁₂ , C ₃₂ and C ₃₄ is easily changed, have.

The conductive terminal 21 may be connected to the feeding part of the RF system and the conductive terminal 23 may be connected to the antenna depending on the impedance characteristic of the antenna and the structure of the terminal.

Although the embodiments of the present invention have been described above, various modifications and changes may be made by those skilled in the art. Such changes and modifications are intended to fall within the scope of the present invention unless they depart from the scope of the present invention. The scope of the present invention should be determined by the following claims.

10: Ceramic body
11, 12, 13, 14, 15, 16: Ceramic sheet
21, 22, 23, 24: conductive terminals
25: Ground terminal
100: first resonance frequency block
200: second resonance frequency block
111, 112, 121, 122, 211, 212, 221, 222:
130: coil 1
230: coil 2
131, 132, 133, 231, 232, 233: Coil pattern
101 to 106, 201 to 206: via holes
241 ~ 246: Connection pattern

Claims (8)

An antenna bandwidth extension device mounted on a circuit board so as to be electrically connected between an RF system and an antenna,
A first conductive terminal electrically connected to the antenna;
A second conductive terminal electrically connected to the first conductive terminal via a first capacitor;
A first coil electrically connected between the first and second conductive terminals;
A third conductive terminal electrically connected to the feeding portion of the RF system;
A fourth conductive terminal electrically connected to the third conductive terminal via a second capacitor;
A second coil electrically connected between the third and fourth conductive terminals; And
And third and fourth capacitors interposed between the second and third conductive terminals and the first and fourth conductive terminals,
Wherein the second capacitor and the fourth capacitor are connected in parallel and in series to the second coil to constitute a first frequency band resonant circuit which is a low frequency band and the first capacitor and the third capacitor are connected to the first coil A second frequency band resonant circuit which is connected in parallel and in series to form a high frequency band,
Wherein the first and second coils are wound in opposite directions and magnetically coupled to each other. An antenna bandwidth extension device mounted on a circuit board so as to be electrically connected between an RF system and an antenna,
And a first coil electrically connected between the first and second conductive terminals and a second coil electrically connected between the first and second conductive terminals and a second coil electrically connected between the first and second conductive terminals, A ceramic body having a coil; And
And first to fourth capacitors connected between the first to fourth conductive pads formed corresponding to the first to fourth conductive terminals on the circuit board,
Wherein the first conductive terminal is electrically coupled to the antenna and the third conductive terminal is electrically coupled to the feed portion of the RF system such that the second and fourth capacitors are connected in parallel and in series to the second coil, Wherein the first and third capacitors constitute a second frequency band resonant circuit which is connected in parallel and in series to the first coil to constitute a high frequency band,
Wherein the first and second coils are wound in opposite directions and magnetically coupled to each other. The method according to claim 1 or 2,
And wherein the first coil is located within the second coil. The method according to claim 1 or 2,
Wherein the first and second coils have a circular cross section or a polygonal cross section. The method according to claim 1,
And the second and fourth conductive terminals are electrically connected to the ground via an external inductor. A first ceramic sheet in which conductive terminals are formed at four corners of the lower surface, and a ground terminal is formed at the center;
A second ceramic sheet on which a first capacitor pattern is formed;
A plurality of third ceramic sheets on which the first capacitor pattern or the second capacitor pattern and the first and second coil patterns are formed;
And a fourth ceramic sheet on which the first capacitor pattern is formed,
The first and second coil patterns are connected to each other through via holes to form a coil and are magnetically coupled to each other, and the first and second coil patterns are superimposed on each other in a stacked state Thereby forming a capacitor,
Wherein the coil and the capacitor are electrically connected to the conductive terminal through a via hole. A first ceramic sheet in which conductive terminals are formed at four corners of the lower surface, and a ground terminal is formed at the center;
A second ceramic sheet having one connection pattern;
A plurality of third ceramic sheets on which first and second coil patterns are formed;
And a fourth ceramic sheet having another connection pattern formed thereon,
The first and second coil patterns are connected to each other through via holes to form a coil and are magnetically coupled to each other,
Wherein the coil is electrically connected to the conductive terminal via the connection pattern and the via hole. The method according to claim 6 or 7,
Wherein the first and second coil patterns are formed on different ceramic sheets.

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