Chip antenna and chip antenna module including the same

A chip antenna includes a radiation portion having a block shape and a first surface and a second surface opposing each other, and configured to receive and radiate a feed signal as an electromagnetic wave; a first block made of a dielectric material and coupled to the first surface of the radiation portion; a second block made of a dielectric material and coupled to the second surface of the radiation portion; a ground portion having a block shape and coupled to the first block, and configured to reflect the electromagnetic wave radiated by the radiation portion back toward the radiation portion; and a director having a block shape and coupled to the second block, wherein an overall width of the ground portion, the first block, and the radiation portion is 2 mm or less, and the first block has a dielectric constant of 3.5 or more to 25 or less.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 USC 119(a) of Korean Patent Application Nos. 10-2018-0012041 filed on Jan. 31, 2018, and 10-2018-0070357 filed on Jun. 19, 2018, in the Korean Intellectual Property Office, the entire disclosures of which are incorporated herein by reference for all purposes.

BACKGROUND

This application relates to a chip antenna and a chip antenna module including the same.

2. Description of Related Art

Fifth generation (5G) communications systems are commonly implemented in higher frequency (mmWave) bands, such as bands of 10 GHz to 100 GHz, to achieve a higher data rate. To decrease propagation loss of radio waves and increase a transmission distance of the radio waves, beamforming, large-scale multiple-input multiple-output (MIMO), full-dimension MIMO (FD-MIMO), an array antenna, analog beamforming, and large-scale antenna techniques have been discussed in relation to 5G communications systems.

Mobile communications terminals, such as cellular phones, personal digital assistants (PDA), navigation devices, and laptop computers, supporting radio communications have been developed to support functions such as code-division multiple access (CDMA), wireless local area network (WLAN), digital multimedia broadcasting (DMB), and near-field communication (NFC). One of the important components enabling these functions is an antenna.

In a millimeter wave communications band, a wavelength is decreased to several millimeters, and it is thus difficult to use a conventional antenna. Therefore, an antenna module appropriate for the millimeter wave communications band is needed.

SUMMARY

In one general aspect, a chip antenna for radio communications in a millimeter wave communications band is configured to be mounted on a board, receive a feed signal from a signal processing element, and externally radiate the feed signal, and includes a radiation portion having a block shape and a first surface and a second surface opposing each other, and configured to receive and radiate the feed signal as an electromagnetic wave; a first block made of a dielectric material and coupled to the first surface of the radiation portion; a second block made of a dielectric material and coupled to the second surface of the radiation portion; a ground portion having a block shape, coupled to the first block so that the first block is between the ground portion and the radiation portion, and configured to reflect the electromagnetic wave radiated by the radiation portion back toward the radiation portion; and a director having a block shape and coupled to the second block so that the second block is between the director and the radiation portion, wherein an overall width of the ground portion, the first block, and the radiation portion is 2 mm or less, and the first block has a dielectric constant of 3.5 or more to 25 or less.

The second block may be made of the same dielectric material as the first block.

Each of the radiation portion, the ground portion, and the director may include a first conductor bonded to either one or both of the first block and the second block; and a second conductor disposed on a surface of the first conductor.

The first block may have a first surface to which the radiation portion is bonded and a second surface to which the ground portion is bonded, the second block may have a first surface to which the radiation portion is bonded and a second surface to which the director is bonded, and a distance between the first surface and the second surface of the first block may be greater than a distance between the first surface and the second surface of the second block.

The chip antenna of claim1, wherein a distance between a first surface of the ground portion bonded to the first block and a second surface of the ground portion opposing the first surface of the ground portion may be greater than a distance between a first surface of the radiation portion bonded to the first block and a second surface of the radiation portion opposing the first surface of the radiation portion.

A size of the director may be the same as a size of the radiation portion.

A length of the director may be smaller than a length of the radiation portion.

A length of the second block may be the same as a length of the director.

The radiation portion may include a first radiation portion and a second radiation portion spaced apart from each other, and the director may include a first director and a second director spaced apart from each other.

The ground portion may include a first ground portion and a second ground portion spaced apart from each other, the first ground portion may be disposed on a straight line with the first radiation portion and the first director, and the second ground portion may be disposed on a straight line with the second radiation portion and the second director.

In another general aspect, an antenna module includes a board having a surface divided into a ground region, a feeding region, and an element mounting portion; a signal processing element mounted on the element mounting portion and configured to transmit a radiation signal to the feeding region; a chip antenna mounted on one surface of the board and configured to radiate a radiation signal having a horizontal polarization; and a patch antenna disposed on another surface of the board and configured to radiate a radiation signal having a vertical polarization, wherein the chip antenna has a structure in which are sequentially stacked a ground portion having a conductivity and a block shape, a first block made of a dielectric material, a radiation portion having a conductivity and a block shape, a second block made of a dielectric material, and a director having a conductivity and a block shape, the ground portion is mounted on the ground region and the radiation portion is mounted on the feeding region, and the chip antenna and the patch antenna are disposed so that they do not face each other.

The feeding region may include a dummy pad, and the director may be bonded to the dummy pad.

The director may not be electrically connected to the board.

The patch antenna may be disposed only on a region of the board facing either one or both of the ground region and the element mounting portion.

The radiation portion may be spaced apart from the ground region by 0.2 mm or more.

The antenna module may further include another chip antenna having a same structure as the chip antenna so that the antenna module includes two chip antennas, the two chip antennas may be mounted on the board as a pair so that the radiation portions of the two chip antennas face each other and the two chip antennas function as a dipole antenna, and a spacing between the two chip antennas may be 0.2 mm or more to 0.5 mm or less.

The feeding region may be disposed along an edge of the board.

The antenna module may further include a feed pad disposed in the feeding region, and the radiation portion may be configured to directly receive the radiation signal from the signal processing element through the feed pad, and externally radiate the radiation signal.

The patch antenna may include a feeding electrode disposed in the board and electrically connected to the signal processing element; and a non-feeding electrode facing the feeding electrode and spaced apart from the feeding electrode by a predetermined distance.

The antenna module may further include a ground pad disposed on the surface of the board in the ground region; and a feed pad disposed on the surface of the board in the feeding region, wherein the ground portion of the chip antenna may be mounted on the ground pad by an electrically conductive bond, and the radiation portion of the chip antenna may be mounted on the feed pad by an electrically conductive bond.

In another general aspect an antenna module includes a board having a surface divided into a ground region and a feeding region, and including wiring layers; a signal processing element mounted on the board and configured to transmit a radiation signal to the feeding region; and two chip antennas mounted on one surface of the board in a pair and configured to radiate a radiation signal having a horizontal polarization and function as a dipole antenna, wherein each of the two chip antennas has a structure in which are sequentially stacked a ground portion having a conductivity and a block shape, a first block made of a dielectric material, a radiation portion having a conductivity and a block shape, a second block made of a dielectric material, and a director having a conductivity and a block shape, the board further includes two feed pads respectively bonded to the radiation portions of the two chip antennas, and two feed vias respectively extending from the two feed pads and connected to the wiring layers of the board, the two feed pads are spaced apart from each other on a straight line so that end portions of the two feed pads face each other, and the two feed vias respectively extend from the end portions of the two pads facing each other.

The antenna module may further include a patch antenna disposed on another surface of the board and configured to radiate a radiation signal having a vertical polarization.

In another general aspect, a chip antenna includes a ground portion having a block shape; a first block bonded to the ground portion; a radiation portion having a block shape, bonded to the first block, and configured to emit electromagnetic waves; a second block bonded to the radiation portion; a director having a block shape, bonded to the second block, and configured to emit an electromagnetic wave constructively interfering with the electromagnetic wave emitted by the radiation portion; wherein the ground portion, the radiation portion, and the director are made of a first type of material, the first block and the second block are made of a second type of material different from the first type of material, and an overall width of the ground portion, the first block, and the radiation portion is 2 mm or less.

The ground portion, the radiation portion, and the director may be made of a conductive material, and the first block and the second block may be made of a dielectric material having a dielectric constant of 3.5 or more to 25 or less.

The ground portion may be configured to reflect the electromagnetic wave radiated by the radiation portion back toward the radiation portion.

The ground portion and the radiation portion may be coupled to opposite sides of the first block, the radiation portion and the director may be coupled to opposite sides of the second block, and a width of the ground block in a direction from the ground portion to the reflector is greater than a width of the radiation portion in the direction from the ground portion to the reflector.

In another general aspect, an antenna module includes a board including a ground region and a feeding region; a chip antenna mounted on a surface of the board, configured to radiate a radiation signal in a first direction, and having a structure in which are sequentially stacked a ground portion having a block shape and electrically connected to the ground region, a first block, a radiation portion having a block shape and electrically connected to the feeding region, a second block, and a director; and a patch antenna disposed in or on the board so that the patch antenna does not overlap the chip antenna in a direction perpendicular to the surface of the board, and configured to radiate a radiation signal in a second direction different from the first direction.

The chip antenna may be mounted on the surface of the board so that the radiation portion of the chip antenna is spaced apart from the ground region by 0.2 mm or more.

The ground portion, the radiation portion, and the director may be made of a conductive material, and the first block and the second block may be made of a dielectric material having a dielectric constant of 3.5 or more to 25 or less.

DETAILED DESCRIPTION

A chip antenna module described herein may be operated in a high-frequency band, and may be operated in a millimeter wave communications band. For example, the chip antenna module may be operated in a frequency band between 20 GHz to 60 GHz. In addition, the chip antenna module described herein may be mounted in an electronic device configured to receive or transmit and receive radio signals. For example, a chip antenna may be mounted in a mobile phone, a portable laptop computer, or a drone.

FIG. 1is a perspective view illustrating an example of a chip antenna,FIG. 2is an exploded perspective view of the chip antenna illustrated inFIG. 1, andFIG. 3is a cross-sectional view taken along the line III-III′ ofFIG. 1.

An example of a chip antenna will be described with reference toFIGS. 1 through 3.

The chip antenna100generally has a hexahedral shape, and is mounted on a board by a conductive adhesive or solder.

The chip antenna100includes a body portion120, a radiation portion130a, a ground portion130b, and a director130c.

The body portion120includes a first block120adisposed between the radiation portion130aand the ground portion130b, and a second block120bdisposed between the radiation portion130aand the director130c.

Therefore, the chip antenna100is configured by sequentially stacking the ground portion130bhaving conductivity and having a block shape, the first block120amade of a dielectric material, the radiation portion130ahaving conductivity and having a block shape, the second block120bmade of a dielectric material, and the director130chaving conductivity and having a block shape.

Both the first block120aand the second block120bhave a hexahedral shape, and are made of the dielectric material. For example, the body portion120may be made of a polymer or a ceramic sintered body having a dielectric constant.

The chip antenna100is used in a millimeter wave communications band. Therefore, an overall width W4+W1+W3of the radiation portion130a, the first block, and the ground portion130bis 2 mm or less so as to correspond to a wavelength in the millimeter wave communications band. In addition, the chip antenna100has a length L selected in a range of 0.5 mm to 2 mm to tune a resonant frequency in the millimeter wave communications band.

When a dielectric constant of the first block120ais less than 3.5, a distance between the radiation portion130aand the ground portion130bneeds to be increased for the chip antenna100to be normally operated.

As a test result, it was determined that in a case in which the dielectric constant of the first block120ais less than 3.5, the chip antenna100performed a normal function in the band of 20 GHz to 60 GHz when the overall width W4+W1+W3of the radiation portion130a, the first block, and the ground portion130bis 2 mm or more. However, when the chip antenna is configured so that the overall width W4+W1+W3is greater than 2 mm, an overall size of the chip antenna100is increased, making it difficult to mount the chip antenna100in a thin portable device.

In addition, when the dielectric constant of the first block120aexceeds 25, the overall width W4+W1+W3needs to be decreased to 0.3 mm or less. In this case, it was determined that antenna performance was deteriorated.

Therefore, to maintain the antenna performance at an acceptable level while allowing the overall width W4+W1+W3to be 2 mm or less, in this example, the first block120ais made of a dielectric material having a dielectric constant of 3.5 or more to 25 or less.

The second block120bis made of the same material as the first block120a. A width W2of the second block120ais 50 to 60% of a width W1of the first block120a. In addition, a length L and a thickness T of the second block120bare the same as those of the first block.

Therefore, the second block120bis made of the same material as the first block120aand has the same length and thickness as the first block120a, and has a width different from that of the first block120a.

However, the second block120bis not limited thereto, but may also be made of a material different from that of the first block120aif desired. The second block120bmay be made of a material having a dielectric constant different from that of a material of the first block120aif desired. For example, the second block120bmay be made of a material having a dielectric constant higher than that of the material of the first block120a.

The radiation portion130ahas a first surface coupled to a first surface of the first block120a. In addition, the ground portion130bis coupled to a second surface of the first block120a. The first surface and the second surface are opposite surfaces of the first block120ahaving the hexahedral shape.

In addition, a second surface of the radiation portion130ais coupled to a first surface of the second block120b, and the director130cis coupled to a second surface of the second block120b. The first surface and the second surface of the second block120bare opposite surfaces of the second block120bhaving the hexahedral shape.

In this example, the width W1of the first block120ais a distance between the first surface and the second surface of the first block120a. In addition, the width W2of the second block120bis a distance between the first surface and the second surface of the second block120b. Therefore, a direction from the first surface toward the second surface (or a direction from the second surface toward the first surface) is a width direction of the first block120aor the chip antenna100.

In addition, widths W3and W4of the ground portion130band the radiation portion130aand a width W5of the director130care distances in the width direction of the chip antenna100described above. Therefore, the width W4of the radiation portion130ais the shortest distance from a bonded surface of the radiation portion130abonded to the first surface of the first block120ato a bonded surface of the radiation portion130abonded to the second block120b, and the width W3of the ground portion130bis the shortest distance from a bonded surface (a first surface) of the ground portion130bbonded to the second surface of the first block120ato an opposite surface (a second surface) of the ground portion130bopposite to the bonded surface (the first surface) of the ground portion130b.

In addition, the width W5of the director130cis the shortest distance from a bonded surface of the director130cbonded to the second block120bto an opposite surface of the director130copposite to the bonded surface of the director130c.

The radiation portion130ais in contact with only one of six surfaces of the first block120a, and is coupled to the first block120a. Likewise, the ground portion130bis in contact with one of the six surfaces of the first block120a, and is coupled to the first block120a.

As described above, the radiation portion130aand the ground portion130bare not disposed on surfaces of the first block120aother than the first surface and the second surface of the first block120a, and are disposed in parallel with each other with the first block120ainterposed therebetween.

When the radiation portion130aand the ground portion130bare only coupled to the first surface and the second surface of the first block120a, respectively, the chip antenna has a capacitance due to a dielectric material (the first block120a) between the radiation portion130aand the ground portion130b. Therefore, a coupling antenna may be designed or a resonant frequency may be tuned using the dielectric material.

The director130chas the same size as the radiation portion130a, is in contact with only one of six surfaces (the second surface) of the second block120b, and is coupled to the second block120b.

Therefore, the director130cis spaced apart from the radiation portion130aby the second block120b, and is disposed in parallel with the radiation portion130a.

As described above, the width W2of the second block120bis smaller than the width W1of the first block120a, and thus the radiation portion130ais closer to the director130cthan the ground portion130b.

FIGS. 4A and 4Bare graphs illustrating measurement results of radiation patterns of chip antennas, whereinFIG. 4Ais a graph illustrating a measurement result of a radiation pattern of a chip antenna in which the second block120band the director130care omitted, andFIG. 4Bis a graph illustrating a measurement result of a radiation pattern of the chip antenna100including the second block120band the director130cand illustrated inFIG. 1.

The chip antenna used in the present measurement was configured so that the widths W4, W3, and W5of the radiation portion130a, the ground portion130b, and the director130care each 0.2 mm, the width W1of the first block120ais 0.6 mm, the width W2of the second block120bis 0.3 mm, and a thickness T is 0.5 mm.

Referring toFIG. 4A, the chip antenna that does not include the director130chas a gain of 3.54 dBi at 28 GHz, and referring toFIG. 4B, the chip antenna100that includes the director130chas a gain of 4.25 dBi at 28 GHz. Therefore, it was confirmed that a gain is improved in the chip antenna100of this example.

Therefore, it may be appreciated that the radiation efficiency is significantly improved when the chip antenna100includes the director130cas in this example.

In the chip antenna100of this example, it was determined that as the widths W4and W3of the radiation portion130aand the ground portion130bare increased, a reflection loss S11was decreased. In addition, it was determined that the reflection loss S11is decreased at a high decrease rate when the widths W4and W3of the radiation portion130aand the ground portion130bare 100 μm or less, and is decreased at a relatively low decrease rate when the widths W4and W3of the radiation portion130aand the ground portion130bexceed 100 μm.

Therefore, in this example, each of the width W4of the radiation portion130aand the width W3of the ground portion130bare defined to be 100 μm or more.

In addition, when the widths W4and W3of the radiation portion130aand the ground portion130bare greater than the width W1of the first block120a, the radiation portion130aand the ground portion130bmay be separated from the body portion120by an external impact or when mounting the chip antenna100on the board. Therefore, in this example, maximum widths W4and W3of the radiation portion130aand the ground portion130bare defined to be 50% or less of the width W1of the first block120a.

To mount the chip antenna in the thin portable device, the overall width W4+W1+W3of the radiation portion130a, the first block120a, and the ground portion130bneeds to be 2 mm or less as described above. Therefore, in this example, when the radiation portion130aand the ground portion130bhave the same width, maximum widths of the radiation portion130aand the ground portion130bare defined to be approximately 500 μm and minimum widths of the radiation portion130aand the ground portion130bare defined to be approximately 100 μm. However, the widths of the radiation portion130aand the ground portion130bare not limited thereto, and when the widths of the radiation portion130aand the ground portion130bare different from each other, the maximum widths of the radiation portion130aand the ground portion130bdescribed above may be changed.

In the chip antenna100of this example, when the length L of the chip antenna100is increased, the reflection loss S11is decreased, and a resonant frequency is decreased. Therefore, the length L of the chip antenna may be adjusted to optimize the resonant frequency or decrease the reflection loss S11.

All of the radiation portion130a, the ground portion130b, and the director130care made of the same material.

As illustrated inFIG. 3, each of the radiation portion130a, the ground portion130b, and the director130cinclude a first conductor131and a second conductor132.

The first conductor131is a conductor directly bonded to the first block120aand the second block120b, and has a block shape. In addition, the second conductor132is formed as a layer on a surface of the first conductor131.

The first conductor131is formed on the first block120aor the second block120bby a printing process or a plating process, and may be made of a metal selected from Ag, Au, Cu, Al, Pt, Ti, Mo, Ni, and W, or an alloy of two or more metals selected from Ag, Au, Cu, Al, Pt, Ti, Mo, Ni, and W. Alternatively, the first conductor131may also be made of a conductive paste or a conductive epoxy in which an organic material such as a polymer or a glass is contained in a metal.

The second conductor132is formed on the surface of the first conductor131by a plating process. The second conductor132may be formed by sequentially stacking a nickel (Ni) layer and a tin (Sn) layer or sequentially stacking a zinc (Zn) layer and a tin (Sn) layer, but is not limited thereto.

The first conductor131is formed to have the same thickness and height as those of each of the first block120aand the second block120b. Therefore, as illustrated inFIG. 3, each of the radiation portion130a, the ground portion130b, and the director130chave a thickness T2greater than a thickness T1of the first block120adue to the second conductor132formed as a layer on the surface of the first conductor131.

The chip antenna100configured as described above may be used in a high frequency band of 20 GHz or more to 60 GHz or less, and the overall width W4+W1+W3of the radiation portion130a, the first block120a, and the ground portion130band the overall length are 2 mm or less so that the chip antenna100may be easily mounted in the thin portable device.

In addition, since the radiation portion130aand the ground portion130bare in contact with only the first and second surface of the first block120a, respectively, the resonant frequency may be easily tuned.

In addition, the chip antenna100includes the director130c, and the ground portion130bfunctions as a reflector. Therefore, a rectilinear propagation property of a beam and gain are improved so that a radiation efficiency is improved.

Although not illustrated, bonding portions may be interposed between the dielectric materials and the conductors. The bonding portions may be disposed between the first block120aand the radiation portion130aand between the first block120aand the ground portion130b. In addition, the bonding portions may be disposed between the second block120band the radiation portion120aand between the second block120band the director120c.

The bonding portions bond the first conductor131and the body portion120to each other. Therefore, the radiation portion130a, the ground portion130b, and the director130care bonded to the body portion120through the bonding portions.

The bonding portions are provided to firmly couple the radiation portion130a, the ground portion130b, and the director130cto the body portion120. Therefore, the bonding portion are made of a material that may be easily bonded to the first conductors131of the radiation portion130a, the ground portion130b, the director130c, and the body portion120.

For example, the bonding portion may be made of any one or any combination of any two or more of Cu, Ti, Pt, Mo, W, Fe, Ag, Au, and Cr. Alternatively, the bonding portion may be made of any one or any two or more of a silver (Ag) paste, a copper (Cu) paste, a silver-copper (Ag—Cu) paste, a nickel (Ni) paste, and a solder paste.

Alternatively, the bonding portion may be made of a material such as an organic chemical material, a glass, SiO2, graphene, or graphene oxide.

The bonding portion may have one layer, and may have a thickness of, for example, 10 μm to 50 μm. However, the bonding portion is not limited thereto, but may be modified in various ways. For example, the bonding portion may be made by stacking a plurality of layers.

However, the chip antenna100is not limited to the abovementioned configuration, but may be modified in various ways.

FIGS. 5 through 9are perspective views illustrating other examples of a chip antenna.

In a chip antenna illustrated inFIG. 5, the director130chas a length L2smaller than a length L1of the radiation portion130a. For example, the length L2of the director130cmay be 5% smaller than the length L1of the radiation portion130a, but is not limited thereto.

In this example, the center of the director130cis disposed in a straight line with the center of the radiation portion130a.

In a chip antenna illustrated inFIG. 6, the second block120bas well as the director130chave a length L2smaller than the length L1of the radiation portion130a. In this example, the second block120bhas the same length L2as that of the director130c. Therefore, the length L2of the director130cand the second block120bmay be 5% smaller than the length L1of the radiation portion130a. However, the director130cand the second block120bare not limited thereto, but may be modified in various ways. For example, the second block120bmay have a length greater or smaller than the length L2of the director130c.

In a chip antenna illustrated inFIG. 7, the ground portion130bhas a width W3greater than a width W4of the radiation portion130a. Since the ground portion130bfunctions as a reflector, a length extension effect may be achieved by increasing the width W3of the ground portion130b.

The chip antenna of this example has a structure similar to that of a Yagi-Uda antenna. Therefore, like the Yagi-Uda antenna, the radiation portion130afunctioning as a radiator radiates an electromagnetic wave toward the director130c, and the director130cradiates an electromagnetic wave induced by the electromagnetic wave radiated by the radiation portion130a. In this case, wavelengths of the electromagnetic waves radiated by the radiation portion130aand the director130cgenerate constructive interference due to a phase difference to increase a gain of the chip antenna. In addition, the radiator130aradiates an electromagnetic wave toward the ground portion130bfunctioning as a reflector, which reflects the electromagnetic wave toward the director130co improve a radiation efficiency of the chip antenna.

In a general Yagi-Uda antenna, the reflector has a length greater than that of the radiator. However, in the chip antenna of this example, the ground portion130bhas a width W3greater than a width W4of the radiation portion130adue to a limitation on a size of the chip antenna. For example, the width W3of the ground portion130bmay be 150% of the width W4of the radiation portion130a, but is not limited thereto.

In a chip antenna illustrated inFIG. 8, the ground portion includes a first ground portion130b1and a second ground portion130b2spaced apart from each other. In addition, the radiation portion includes a first radiation portion130a1and a second radiation portion130a2spaced apart from each other, and the director includes a first director130c1and a second director130c2spaced apart from each other.

All of the first ground portion130b1, the first radiation portion130a1, and the first director130c1are disposed in a straight line. Likewise, all of the second ground portion130b2, the second radiation portion130a2, and the second director130c2are disposed in a straight line.

In the chip antenna of this example, a dipole antenna structure is implemented in one chip antenna.

Therefore, only one chip antenna rather than two chip antennas may be used to configure a dipole antenna structure as illustrated inFIG. 10.

In this example, the first block120ais a single body, but the second block120bis divided into two portions, one of which is disposed between the first radiation portion130a1and the first director130c1, and the other of which is disposed between the second radiation portion130a2and the second director130c2. However, a configuration of the chip antenna of this example is not limited thereto, but may be modified in various ways. For example, the second block120bmay be a single body as is a second block120bto be described with reference toFIG. 9.

In addition, like in the examples illustrated inFIGS. 5 and 6, the first director130c1and the second director130c2may have lengths smaller than lengths of the first radiation portion130a1and the second radiation portion130a2.

In a chip antenna illustrated inFIG. 9, the radiation portion includes a first radiation portion130a1and a second radiation portion130a2spaced apart from each other, and the director includes a first director130c1and a second director130c2spaced apart from each other. In addition, the ground portion130bis a single body.

In addition, the first block120ais a single body and is disposed between the radiation portions130a1and130a2and the ground portion130b, and the second block120bis also a single body and is disposed between the radiation portions130a1and130a2and the directors130c1and130c2.

In the chip antenna of this example, the ground portion130bhas a length greater than lengths of the radiation portion130a1and130a2, and reflection efficiency of an electromagnetic wave is thus improved.

Meanwhile, like in the examples illustrated inFIGS. 5 and 6, the first director130c1and the second director130c2may have lengths smaller than lengths of the first radiation portion130a1and the second radiation portion130a2.

FIG. 10is a partially exploded perspective view of an example of a chip antenna module including the chip antenna illustrated inFIG. 1,FIG. 11is a bottom view of the chip antenna illustrated inFIG. 10, andFIG. 12is a cross-sectional view taken along the line XII-XII′ ofFIG. 10.

Referring toFIGS. 10 through 12, a chip antenna module1includes a board10, an electronic element50, and chip antennas100.

The board10is a circuit board on which circuits or electronic components for a radio antenna are mounted. For example, the board10may be a printed circuit board (PCB) containing one or more electronic components therein or having one or more electronic components mounted on a surface thereof. Therefore, the board10may be provided with circuit wirings electrically connecting the electronic components to each other.

The board10may be a multilayer board formed by repeatedly stacking a plurality of insulating layers17and a plurality of wiring layers16(seeFIG. 12). However, if desired, a double-sided board on which wiring layers are formed on opposite surfaces of one insulating layer may also be used.

Various kinds of boards (for example, a printed circuit board, a flexible board, a ceramic board, or a glass board) may be used as the board10.

A first surface of the board10, which is an upper surface of the board10in the example illustrated inFIGS. 10 through 12, is divided into an element mounting portion11a, a ground region11b, and a feeding region11c.

The element mounting portion11a, which is a region on which the electronic element50is mounted, is disposed inside a ground region11bto be described below. A plurality of connection pads12ato which the electronic element50is electrically connected are disposed in the element mounting portion11a.

The ground region11b, which is a region on which a ground layer16a(seeFIG. 12) is disposed, is disposed surrounding the element mounting portion11a. In this example, the element mounting portion11ahas a rectangular shape. Therefore, the ground region11bhas a rectangular ring shape so as to surround the element mounting portion11a.

Since the ground region11bis disposed along an entire circumference of the element mounting portion11a, the connection pads12aof the element mounting portion11amay be electrically connected to an external device or other components through interlayer connection conductors18(seeFIG. 12) penetrating through the insulating layers17of the board10.

A plurality of ground pads12bare formed in the ground region11b. When the ground layer is formed from the uppermost wiring layer16of the board10, like the ground layer16ainFIG. 12, the ground pads12bmay be formed by partially opening an insulation protective layer19(seeFIG. 12) covering the ground layer. However, the ground pads are not limited thereto, and when the ground layer is not formed from the uppermost wiring layer16of the board10, but is disposed between other wiring layers16, the ground pads12bmay be formed from the uppermost wiring layer16, and the ground pads12band the ground layer may be connected to each other through interlayer connection conductors (not illustrated, but like interlayer connection conductors18).

The ground pads12bare disposed in pairs with feed pads12cto be described below. Therefore, the ground pads12bare disposed adjacent to the feed pads12c.

The feeding region11cis disposed outside the ground region11b. In this example, the feeding region11cis a region outside two sides of the ground region11b. Therefore, the feeding region11cis disposed along two edges of the board10. However, a configuration of the feeding region11cis not limited thereto.

A plurality of feed pads12cand a plurality of dummy pads12dare disposed in the feeding region11c. The feed pads12care disposed on the uppermost wiring layer, like the connection pads12a, and may be electrically connected to the electronic element50or other components through interlayer connection conductors penetrating through the insulating layers of the board10.

In this example, the feed pads12care disposed in pairs. Referring toFIG. 10, a total of four pairs of feed pads12care disposed. However, a configuration of the feed pads12cis not limited thereto, and the number of pairs of feed pads12cmay be changed depending on a size of the chip antenna module or other factors.

In addition, in this example, the feed pad12chas a length that is the same or substantially the same as a length of a lower surface (or a bonded surface) of the radiation portion130a. In addition, an area of the feed pad12cmay be in a range of 80% to 120% of an area of the lower surface of the radiation portion130aof the chip antenna100. However, the feed pads are not limited thereto.

In this example, two feed pads12cdisposed in a pair are linear strips, and are spaced apart from each other on a straight line so that end portions thereof face each other.

When the area of the feed pad12cis substantially the same as the area of the lower surface of the radiation portion130aof the chip antenna100as described above, a bonding reliability between the chip antenna100and the board10is improved.

In addition, in this example, interlayer connection conductors18b(hereinafter referred to as feed vias) connected to the feed pads12care disposed at end portions of the feed pads12c. The feed vias18bextend into the board10in a direction perpendicular to the feed pads12c, and are connected to the wiring layers in the board10.

As described above, the two feed pads12care disposed in a pair. Therefore, two feed vias18bconnected to the feed pads12care also disposed in a pair.

The two feed vias18bdisposed in a pair are disposed at end portions of the two feed pads12cdisposed in a pair at which the two feed pads12cdisposed in a pair face each other, and are parallel to each other. The feed vias18bare disposed adjacent to each other. For example, the two feed vias18bmay be spaced apart from each other by 0.5 mm or less. In addition, a distance between the two feed vias18bmay be the same or substantially the same as a distance between the two feed pads12cdisposed in a pair.

The plurality of dummy pads12dare disposed on the uppermost wiring layer, like the feed pads12c. However, the dummy pads12dare not electrically connected to other components of the board, and are bonded to the directors130cof the chip antennas100mounted on the board.

The dummy pads12dare not provided to electrically connect the directors130cand the circuits in the board10to each other, but are provided to more firmly bond the chip antennas100to the board10. Therefore, the dummy pads12dmay be omitted if the chip antennas100can be firmly fixed to the board10by only the feed pads12cand the ground pads12b. In this case, the directors130cwill be in contact with the board10, but will not be electrically connected to the board10.

The element mounting portion11a, the ground region11b, and the feeding region11cconfigured as described above are divided depending on a shape or a position of the ground layer16adisposed thereon, and are protected by the insulation protective layer19inFIG. 12stacked and disposed on the uppermost wiring layer and uppermost insulating layer. In addition, the connection pads12a, the ground pads12b, the feed pads12c, and the dummy pads12dare externally exposed in pad form through openings formed by removing portions of the insulation protective layer19.

A configuration of the feed pad12cis not limited to the abovementioned configuration, but may be modified in various ways. For example, an area of the feed pad12cmay be half or less of an area of the lower surface (or the bonded surface) of the radiation portion130aof the chip antenna100. In this case, the feed pad12cmay have a circular shape rather than linear strip shape, and is not bonded to the entirety of the lower surface of the radiation portion130a, but is bonded to only a portion of the lower surface of the radiation portion130a.

A patch antenna90is disposed in the board10or on a second surface, which is a lower surface, of the board10.

In this example, patch antenna90is formed from a wiring layer16provided on the second or lower surface of the board10. However, the patch antenna is not limited thereto.

As illustrated inFIGS. 11 and 12, the patch antenna90includes a feeding portion91including a feeding electrode92and a non-feeding electrode94.

In this example, the patch antenna90has a plurality of feeding portions91distributed and arranged on the second surface of the board10. In this example, the number of feeding portions91may be four, but is not limited thereto.

In this example, the patch antenna90is configured so that portions thereof (for example, the non-feeding electrode94) are disposed on the second surface of the board10. However, the patch antenna90is not limited thereto, but may be modified in various ways. For example, the entirety of the patch antenna90may be disposed in the board10.

The feeding electrode92is made of a metal layer having a flat shape with a predetermined area, and is made of one conductor plate. The feeding electrode92may have a polygonal shape, and has a rectangular shape in this example, but may be modified in various ways. For example, the feeding electrode92may have a circular shape.

The feeding electrode92is connected to the electronic element50through the interlayer connection conductors18. In this example, the interlayer connection conductors18penetrate through a second ground layer97bto be described below and are connected to the electronic element50.

The non-feeding electrode (or parasitic electrode)94is spaced apart from the feeding electrode91by a predetermined distance, and is made of one flat conductor plate having a predetermined area. The non-feeding electrode94has an area that is the same or substantially the same as an area of the feeding electrode92. For example, the non-feeding electrode94may have an area greater than the area of the feeding electrode92so that the non-feeding electrode94may be disposed to face the entirety of the feeding electrode92.

The non-feeding electrode94is disposed adjacent to a surface of the board10as compared to the feeding electrode92so that the non-feeding electrode94may function as a director. Therefore, the non-feeding electrode94is disposed on the lowermost wiring layer16of the board10. In this example, the non-feeding electrode94is protected by an insulation protective layer19disposed on a lower surface of the lowermost wiring layer16and a lowermost insulating layer17of the board10.

In addition, the board10includes a ground structure95. The ground structure95is disposed in the vicinity of the feeding portion91and is configured in a container shape containing the feeding portion91therein as be seen inFIG. 11. To this end, the ground structure95includes a first ground layer97a, a second ground layer97b, and ground vias18a.

Referring toFIG. 12, the first ground layer97ais coplanar with the non-feeding electrode94, and is disposed in the vicinity of the non-feeding electrode94so as to surround the non-feeding electrode94. In this example, the first ground layer97ais spaced apart from the non-feeding electrode94by a predetermined distance.

The second ground layer97bis disposed on a wiring layer16different from a wiring layer16on which the first ground layer97ais disposed. For example, the second ground layer97bmay be disposed between the feeding electrode92and the first (uppermost) surface of the board10. In this example, the feeding electrode92is disposed between the non-feeding electrode94and the second ground layer97b.

The second ground layer97bis entirely disposed on the corresponding wiring layer16, and is partially removed only at a portion at which the interlayer connection conductor18connected to the feeding electrode92is disposed.

The ground vias18aare interlayer connection conductors electrically connecting the first ground layer97aand the second ground layer97bto each other, and a plurality of ground vias18aare arranged along a circumference of the feeding portion91so as to surround the feeding portion91. Although an example in which the ground vias18aare arranged in a row has been described, the ground vias18amay be modified in various ways. For example, the ground vias18amay be arranged in a plurality of rows if desired.

Due to the configuration described above, the feeding portion91is disposed in the ground structure95formed in the container shape by the first ground layer97a, the second ground layer97b, and the ground vias18a. In this example, the plurality of ground vias18aarranged in a row delimit side surfaces of the container shape described above.

In this example, each of the feeding portions91is disposed in the container shape. Therefore, interference between the respective feeding portions91is blocked by the ground structure95. For example, noise transferred in a horizontal direction of the board10is blocked by the side surfaces of the container shape formed by the plurality of ground vias18a.

The ground vias18aform the side surfaces of the container shape, and isolate the feeding portion91from other feeding portions91adjacent thereto. In addition, the ground structure95having the container shape serves as a reflector to improve radiation characteristics of the patch antenna90.

The feeding portion91of the patch antenna90configured as described above radiates a radio signal in a thickness direction (for example, a downward direction) of the board10.

Referring toFIG. 12, in this example, the first ground layer97aand the second ground layer97bare not be disposed in a region facing the feeding region11c(seeFIG. 10) defined on the first surface of the board10. In more detail, in this example, the patch antenna90is disposed in only a region facing the ground region11band the element mounting portion11a. Therefore, the chip antenna100and the patch antenna90are disposed so they do not face each other. This configuration significantly reduces interference between a radio signal radiated from a chip antenna100to be described below and the ground structure95.

Although an example in which the patch antenna90includes the feeding electrode92and the non-feeding electrode94has been described, the patch antenna90may be modified in various ways. For example, the patch antenna90may be configured to include only the feeding electrode92if desired.

The patch antenna90configured as described above radiates a radio signal in the thickness direction of the board10(that is, in a direction perpendicular to the board10).

The electronic element50is mounted on the element mounting portion11aof the board10. Although an example in which one electronic element50is mounted on the element mounting portion11aof the board10has been described, a plurality of electronic elements may also be mounted on the element mounting portion11aof the board10if desired.

The electronic element50includes at least one active element such as a signal processing element applying a radiation signal to the feeding portion91of the antenna. In addition, the electronic element50may also include a passive element if needed.

The chip antenna100may be any one of the chip antennas described in this application, and may be mounted on the board by a conductive adhesive or solder.

In the chip antenna100, the ground portion130bis mounted on the ground region11b, and the radiation portion130aand the director130care mounted on the feeding region11c. In more detail, the ground portion130b, the radiation portion130a, and the director130cof the chip antenna100are mounted on the board10by being bonded to the ground pad12b, the feed pad12c, and the dummy pad12d, respectively.

The chip antenna module1configured as described above radiates radio waves having a horizontal polarization using the chip antennas100, and radio waves having a vertical polarization using the patch antennas90. That is, the chip antennas100are disposed at positions adjacent to edges of the first surface of the board10and radiate radio waves in a plane direction of the board10(for example, a horizontal direction of the board10), and the patch antennas90are disposed on the second surface of the board10and radiate radio waves in the thickness direction of the board10(for example, a vertical direction of the board10). Therefore, a radiation efficiency of the radio waves is improved.

In addition, in the chip antenna module1, two chip antennas100disposed in a pair function as a dipole antenna.

The two chip antennas100disposed in a pair are spaced apart from each other by a predetermined distance, and form one dipole antenna structure. A distance between the two chip antennas100is 0.2 mm to 0.5 mm. When the distance is less than 0.2 mm, interference is generated between the two chip antennas100, and when the distance is 0.5 mm or more, a function of the dipole antenna is deteriorated.

Another possibility would be to form the dipole antenna from the wiring layers of the board10instead of using the chip antennas100. However, in this example, a radiation portion of the dipole antenna needs to have a length of a half wavelength of a corresponding frequency, and an area occupied by a feeding region in the board10in which the dipole antenna would be disposed in the board10would thus be relatively large.

On the other hand, when a pair of the chip antennas100are used to form the dipole antenna as in this example, a size of the chip antennas100may be significantly reduced by a dielectric constant (for example, 10 or more) of the first block120a.

For example, when the dipole antenna is formed from wiring patterns on the first surface of the board10, a feeding line of the dipole antenna needs to be spaced apart from the ground region11bby 1 mm or more. On the other hand, when the pair of the chip antennas100are used, the feed pads12cmay be spaced apart by 1 mm or less from the ground region11b.

Therefore, a size of the feeding region11cmay be reduced in the example of using the pair of chip antennas100as compared to the example of using the dipole antenna formed from the wiring patterns, and an overall size of the chip antenna module1may thus be significantly reduced.

If a distance P between the radiation portion130aof the chip antenna100and the ground region11bis less than 0.2 mm, a resonant frequency of the chip antenna100may be changed. Therefore, in this example, the radiation portion130aof the chip antenna100and the ground region11bof the board10are spaced apart from each other in a range of 0.2 or more to 1 mm or less.

In addition, the chip antenna100is disposed at a position at which it does not face the patch antennas90in the vertical direction of the board10. The position at which the chip antenna100does not face the patch antennas90in the vertical direction of the board10is a position at which the chip antenna100does not overlap the patch antennas90when the chip antenna100is projected on the second surface of the board10in the vertical direction of the board10.

In this example, the chip antenna100is also disposed so that it does not face the ground structure95. However, the chip antenna is not limited thereto, but may also be disposed to partially face the ground structure95if desired.

The configuration of the chip antenna module1described significantly reduces interference between the chip antennas100and the patch antennas90.

FIG. 13is a schematic perspective view illustrating an example of a mobile terminal in which several of the chip antenna module illustrated inFIG. 10are mounted.

Referring toFIG. 13, four of the chip antenna module1illustrated inFIG. 10are disposed at corner portions of a mobile terminal200. In this example, the chip antenna modules1are disposed so that the chip antennas100are adjacent to corners (or vertices) of the mobile terminal200.

AlthoughFIG. 13shows an example in which the chip antenna modules1are disposed at all of four corners of the mobile terminal200, an arrangement in which the chip antenna modules1are disposed is not limited thereto, but may be modified in various ways if desired. For example, when an internal space of the mobile terminal is insufficient, only two chip antenna modules1may be disposed at diagonally opposite corners of the mobile terminal200.

In addition, the chip antenna modules1may be mounted in the mobile terminal200so that feeding regions of the chip antennal modules1are disposed adjacent to edges of the mobile terminal200. Therefore, radio waves radiated by the chip antennas100of the chip antenna modules1may be radiated in a plane direction of the mobile terminal200toward the outside of the mobile terminal200. In addition, radio waves radiated by the patch antennas90of the chip antenna modules1may be radiated in a thickness direction of the mobile terminal200.

As described above, the chip antenna module1uses a pair of the chip antennas100rather than a dipole antenna having a wiring form, and a size of the chip antenna module1is thus significantly reduced. In addition, a transmission and reception efficiency of signals is improved.