Antenna substrate and front end module including the same

Abstract

An antenna substrate of the disclosure includes a plurality of antenna layers stacked so as to be spaced apart from each other in a vertical direction, an antenna insulating layer disposed between the plurality of antenna layers, and a transmission line including a capacitive power feeding unit configured to feed power to the plurality of antenna layers in a capacitive manner with the antenna insulating layer interposed therebetween. The plurality of antenna layers includes a plurality of high-frequency antenna layers disposed above the capacitive power feeding unit so as to be stacked in the vertical direction and configured to radiate a high-frequency signal in a first radio frequency band and a low-frequency antenna layer disposed below the capacitive power feeding unit and configured to radiate a low-frequency signal in a second radio frequency band lower than the first radio frequency band.

Description

ANTENNA SUBSTRATE AND FRONT END MODULE INCLUDING THE SAME

[0001] Embodiments relate to an antenna substrate and a front end module including the same.

[0002] In order to meet increase in demand for wireless data traffic, efforts have recently been made to develop an improved 5thgeneration (5G) communication system or a pre-5G communication system.

[0003] In order to achieve a high data transmission rate, a 5G communication system uses the millimeter wave (mmWave) frequency band.

[0004] In order to reduce propagation loss of radio waves and increase a transmission distance of radio waves in an ultra-high frequency band, integration technologies, such as beamforming, massive multiple-input multiple-output (massive MIMO), and array antenna, have been developed and applied to the 5G communication system. An antenna substrate that radiates a signal in this frequency band may increase in size. However, miniaturization of the antenna substrate is required for mounting thereof in smartphones, etc. Therefore, various research with the goal of increasing the bandwidth of the antenna substrate without increase in the size thereof is underway.

[0005] Embodiments provide a small antenna substrate having a wide bandwidth in a wide high-frequency range and a front end module including the same.

[0006] An antenna substrate according to an embodiment may include a plurality of antenna layers stacked so as to be spaced apart from each other in a vertical direction, an antenna insulating layer disposed between the plurality of antenna layers, and a transmission line including a capacitive power feeding unit configured to feed power to the plurality of antenna layers in a capacitive manner with the antenna insulating layer interposed therebetween, wherein the plurality of antenna layers may include a plurality of high-frequency antenna layers disposed above the capacitive power feeding unit so as to be stacked in the vertical direction and configured to radiate a high-frequency signal in a first radio frequency band and a low-frequency antenna layer disposed below the capacitive power feeding unit and configured to radiate a low-frequency signal in a second radio frequency band lower than the first radio frequency band.

[0007] In an example, the plurality of high-frequency antenna layers may include an upper high-frequency antenna layer and a lower high-frequency antenna layer disposed between the upper high-frequency antenna layer and the capacitive power feeding unit in the vertical direction.

[0008] In an example, the transmission line may further include an upper via configured to connect the capacitive power feeding unit to the lower high-frequency antenna layer.

[0009] In an example, the transmission line may further include a main via including an end portion passing through the low-frequency antenna layer, a lower via including an end connected to the capacitive power feeding unit, and a via connection part configured to connect the other end of the lower via to the end portion of the main via.

[0010] In an example, the lower high-frequency antenna layer may have a larger planar area than the upper high-frequency antenna layer.

[0011] In an example, the upper high-frequency antenna layer may include a first central portion and a plurality of peripheral portions disposed around the first central portion so as to be spaced apart from the first central portion by a predetermined gap in a horizontal direction.

[0012] In an example, the lower high-frequency antenna layer may include a second central portion.

[0013] In an example, the second central portion may include an edge overlapping the gap in the vertical direction.

[0014] In an example, the entirety of the first central portion may overlap the second central portion in the vertical direction.

[0015] A front end module according to another embodiment may include a plurality of antenna areas spaced apart from each other in a horizontal direction, wherein each of the plurality of antenna areas may include an antenna unit, the antenna unit may include a plurality of antenna layers stacked so as to be spaced apart from each other in a vertical direction, an antenna insulating layer disposed between the plurality of antenna layers, and a transmission line including a capacitive power feeding unit configured to feed power to the plurality of antenna layers in a capacitive manner with the antenna insulating layer interposed therebetween, and the plurality of antenna layers may include a plurality of high-frequency antenna layers disposed above the capacitive power feeding unit so as to be stacked in the vertical direction and configured to radiate a high-frequency signal in a first radio frequency band and a low-frequency antenna layer disposed below the capacitive power feeding unit and configured to radiate a low-frequency signal in a second radio frequency band lower than the first radio frequency band.

[0016] As is apparent from the above description, an antenna substrate and a front end module including the same according to embodiments may have a wide bandwidth in a high-frequency band while having a small volume, and may cover a wide frequency band of 37 GHz to 43.5 GHz.

[0017] Arrangements and embodiments may be described in detail with reference to the following drawings in which like reference numerals refer to like elements and wherein:

[0018] FIG. 1 is a plan view of an antenna substrate according to an embodiment;

[0019] FIG. 2 is a perspective view of the antenna substrate shown in FIG. 1;

[0020] FIG. 3 is a cross-sectional view taken along line I-I’ shown in FIG. 1;

[0021] FIG. 4 is a schematic perspective view of the antenna substrate according to the embodiment;

[0022] FIG. 5 is a perspective view of the antenna substrate according to the embodiment;

[0023] FIG. 6A is a cross-sectional view of the antenna substrate shown in FIG. 5;

[0024] FIG. 6B is a plan view of the antenna substrate shown in FIG. 6A;

[0025] FIGs. 7A and 7B are plan views of embodiments of first and second power feeding plates shown in FIG. 5;

[0026] FIG. 8 is a cross-sectional view of an antenna substrate according to a comparative example;

[0027] FIG. 9 is a graph indicating return loss for the antenna substrate according to the comparative example;

[0028] FIG. 10 is a graph indicating return loss for the antenna substrate according to the embodiment; and

[0029] FIG. 11 is a block diagram of a front end module according to an embodiment.

[0030] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0031] The technical spirit of the disclosure is not limited to the embodiments to be described, and may be implemented in various other forms, and one or more of the components may be selectively combined and substituted for use without exceeding the scope of the technical spirit of the disclosure.

[0032] In addition, terms (including technical and scientific terms) used in the embodiments of the disclosure, unless specifically defined and described explicitly, are to be interpreted as having meanings that may be generally understood by those having ordinary skill in the art to which the disclosure pertains, and meanings of terms that are commonly used, such as terms defined in a dictionary, should be interpreted in consideration of the context of the relevant technology.

[0033] Further, the terms used in the embodiments of the disclosure are for explaining the embodiments and are not intended to limit the disclosure. In this specification, the singular forms may also include plural forms unless otherwise specifically stated in a phrase, and in the case in which “at least one (or one or more) of A, B, or C” is stated, it may include one or more of all possible combinations of A, B, and C.

[0034] In addition, in describing the components of the embodiments of the disclosure, terms such as “first”, “second”, “A”, “B”, “(a)”, and “(b)” can be used. Such terms are only for distinguishing one component from another component, and do not determine the nature, sequence, or procedure of the corresponding constituent elements.

[0035] In addition, when it is described that a component is “connected”, “coupled” or “joined” to another component, the description may include not only being directly “connected”, “coupled” or “joined” to the other component but also being “connected”, “coupled” or “joined” by another component between the component and the other component.

[0036] In addition, in the case of being described as being formed or disposed “above (on)” or “below (under)” another component, the description includes not only the case where the two components are in direct contact with each other, but also the case where one or more other components are formed or disposed between the two components. In addition, when expressed as “above (on)” or “below (under)”, it may refer to a downward direction as well as an upward direction with respect to one element.

[0037] Hereinafter, an antenna substrate according to an embodiment will be described with reference to the accompanying drawings. Here, the antenna substrate may mean a hybrid antenna substrate, an antenna in package (AIP), an antenna array substrate, an antenna array, etc.

[0038] The antenna substrate 100 will be described using the Cartesian coordinate system (x-axis, y-axis, z-axis) for convenience of description, but may also be described using other coordinate systems. In the Cartesian coordinate system, the x-axis, the y-axis, and the z-axis are perpendicular to each other, but the embodiments are not limited thereto. That is, the x-axis, the y-axis, and the z-axis may intersect each other obliquely. Hereinafter, for convenience of description, the x-axis direction will be referred to as a “first direction”, the y-axis direction will be referred to as a “second direction”, the z-axis direction will be referred to as a “third direction” or a “vertical direction”, and at least one of the x-axis direction or the y-axis direction will be referred to as a “horizontal direction”.

[0039] FIG. 1 is a plan view of the antenna substrate 100 according to an embodiment, and FIG. 2 is a perspective view of the antenna substrate 100 shown in FIG. 1.

[0040] The antenna substrate 100 according to the embodiment may include a plurality of antenna areas arranged so as to be spaced apart from each other in the horizontal direction. For example, as shown in FIGs. 1 and 2, the antenna substrate 100 may include first to fourth antenna areas A1, A2, A3, and A4 arranged in the y-axis direction, which is the horizontal direction. However, the embodiments are not limited thereto. That is, according to another embodiment, the antenna substrate 100 may include more or less than four antenna areas.

[0041] FIG. 3 is a cross-sectional view taken along line I-I’ shown in FIG. 1.

[0042] Hereinafter, the configuration of the third antenna area A3 (hereinafter referred to as an “antenna area”) will be described with reference to FIG. 3. Because each of the other antenna areas A1, A2, and A4 has the same configuration as the third antenna area A3, a duplicate description thereof will be omitted.

[0043] The antenna area 200 according to an embodiment may include an antenna unit ANT and a routing unit ROT. According to another embodiment, the antenna area 200 may further include a core unit CO. That is, the core unit CO may be omitted from the antenna area 200.

[0044] According to one embodiment, as shown in FIG. 3, the antenna unit ANT may be disposed on the core unit CO, the routing unit ROT may be disposed under the core unit CO, and the core unit CO may be disposed between the antenna unit ANT and the routing unit ROT.

[0045] According to another embodiment, the antenna unit ANT and the routing unit ROT may be disposed on the same horizontal plane.

[0046] According to still another embodiment, the antenna unit ANT may be stacked on the routing unit ROT.

[0047] According to still another embodiment, the routing unit ROT and the antenna unit ANT may be disposed so as to be spaced apart from each other, and may be electrically connected to each other via a connection member, e.g., a flexible printed circuit board (FPCB).

[0048] According to still another embodiment, the routing unit ROT and the antenna unit ANT may be disposed so as to be spaced apart from each other, and may be electrically connected to each other via a connection member, e.g., a solder ball or a metal bump.

[0049] Hereinafter, the antenna unit ANT and the routing unit ROT of the antenna area 200 according to the embodiment will be described as being disposed in the structure shown in FIG. 3. However, the embodiments are not limited to any specific arrangement structure of the antenna unit ANT and the routing unit ROT.

[0050] The antenna unit ANT may include a plurality of wiring layers (hereinafter referred to as “antenna layers”) stacked so as to be spaced apart from each other in the vertical direction and an insulating layer (hereinafter referred to as an “antenna insulating layer”). Here, the wiring layer may mean a patch, an antenna patch, a patch antenna, or a patch layer.

[0051] The plurality of antenna layers may be sequentially stacked on the core unit CO, and the antenna insulating layer may be disposed between the plurality of antenna layers.

[0052] In addition, although not shown in FIG. 3, each of the routing unit ROT and the antenna unit ANT may include a transmission line. A current supplied through a port may be fed to a corresponding antenna layer among the plurality of antenna layers through the transmission line disposed in each of the routing unit ROT and the antenna unit ANT.

[0053] For example, the plurality of antenna layers may include first to Mthantenna layers AL1 to ALM sequentially stacked from above to below in the vertical direction on the core unit CO. Here, M is a positive integer of 2 or greater.

[0054] The first antenna layer AL1 may correspond to each of the uppermost layers 120-1, 120-2, 120-3, and 120-4 of the first to fourth antenna areas A1, A2, A3, and A4 shown in FIGs. 1 and 2.

[0055] First to (M-1)thantenna insulating layers DL11 to DL1(M-1) may be disposed between the first to Mthantenna layers AL1 to ALM.

[0056] For example, if M is 7, the antenna unit ANT may include first to seventh antenna layers AL1 to AL7 and first to sixth antenna insulating layers DL11 to DL16 sequentially stacked in the vertical direction from the top thereof to the core unit CO. That is, the first antenna insulating layer DL11 may be disposed between the first antenna layer AL1 and the second antenna layer AL2, the second antenna insulating layer DL12 may be disposed between the second antenna layer AL2 and the third antenna layer AL3, the third antenna insulating layer DL13 may be disposed between the third antenna layer AL3 and the fourth antenna layer AL4, the fourth antenna insulating layer DL14 may be disposed between the fourth antenna layer AL4 and the fifth antenna layer AL5, the fifth antenna insulating layer DL15 may be disposed between the fifth antenna layer AL5 and the sixth antenna layer AL6, and the sixth antenna insulating layer DL16 may be disposed between the sixth antenna layer AL6 and the seventh antenna layer AL7.

[0057] The aforementioned transmission line may be disposed in the routing unit ROT, and the plurality of wiring layers disposed in the routing unit ROT may include a signal pattern, a power pattern, or a resistance pattern. In addition, the routing unit ROT may have combinations of various routing characteristics such as power / data, input / output, and radio frequency (RF) routing.

[0058] Similar to the antenna unit ANT, the routing unit ROT may include a plurality of wiring layers (hereinafter referred to as “routing layers”) and an insulating layer (hereinafter referred to as a “routing insulating layer”).

[0059] The routing insulating layer may be disposed between the plurality of routing layers.

[0060] First to Nthrouting layers RL1 to RLN may be sequentially disposed in the vertical direction from the core unit CO to below. Here, N is a positive integer of 2 or greater. N may be identical to M. In this case, first to (N-1)throuting insulating layers DL21 to DL2(N-1) may be disposed between the first to Nthrouting layers RL1 to RLN.

[0061] The first routing layer RL1 may be a main ground (or ground layer) GND formed in a ground GND pattern.

[0062] Alternatively, the antenna unit ANT may be formed on the routing unit ROT without the core unit CO. In this case, the antenna unit ANT may be formed on the first routing layer RL1, which is the main ground.

[0063] For example, if N is identical to M, i.e., 7, the routing unit ROT may include first to seventh routing layers RL1 to RL7 and first to sixth routing insulating layers DL21 to DL26 sequentially stacked in the vertical direction from the core unit CO. That is, the first routing insulating layer DL21 may be disposed between the first routing layer RL1 and the second routing layer RL2, the second routing insulating layer DL22 may be disposed between the second routing layer RL2 and the third routing layer RL3, the third routing insulating layer DL23 may be disposed between the third routing layer RL3 and the fourth routing layer RL4, the fourth routing insulating layer DL24 may be disposed between the fourth routing layer RL4 and the fifth routing layer RL5, the fifth routing insulating layer DL25 may be disposed between the fifth routing layer RL5 and the sixth routing layer RL6, and the sixth routing insulating layer DL26 may be disposed between the sixth routing layer RL6 and the seventh routing layer RL7.

[0064] The material of each of the first to Mthantenna layers AL1 to ALM, the core unit CO, and the first to Nth routing layers RL1 to RLN described above may include metal, such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), or alloys thereof.

[0065] In addition, each of the first to (M-1)thantenna insulating layers DL11 to DL1(M-1) and the first to (N-1)throuting insulating layers DL21 to DL2(N-1) may be made of a material having insulating properties (hereinafter referred to as an “insulative material”). For example, a thermosetting resin such as an epoxy resin, a thermoplastic resin such as polyimide, or a material containing a reinforcing material such as a glass fiber and / or an inorganic filler together with a thermosetting resin or a thermoplastic resin, e.g., ABF, PID, BCC, or prepreg (PPG), may be used as the insulative material. However, the insulative material is not limited to a resin. For example, a glass plate or a ceramic plate may be used. However, the embodiments are not limited to any specific material of each of the first to (M-1)thantenna insulating layers DL11 to DL1(M-1) and the first to (N-1)throuting insulating layers DL21 to DL2(N-1).

[0066] Hereinafter, an example of the antenna unit ANT in the antenna substrate according to the embodiment will be described with reference to FIG. 4.

[0067] FIG. 4 is a schematic perspective view of the antenna substrate according to the embodiment.

[0068] The antenna substrate shown in FIG. 4 may include a plurality of high-frequency band (HB) antenna layers (hereinafter referred to as “high-frequency antenna layers”) 210, a low-frequency band (LB) antenna layer (hereinafter referred to as a “low-frequency antenna layer”) 212, a transmission line, and an antenna insulating layer.

[0069] In FIG. 4, a white background, except for the plurality of high-frequency antenna layers 210, the low-frequency antenna layer 212, and the transmission line, may correspond to the antenna insulating layer.

[0070] The plurality of high-frequency antenna layers 210 may be disposed so as to be stacked in the vertical direction, and may radiate a high-frequency signal (or HB signal) in a first radio frequency band.

[0071] For example, the plurality of high-frequency antenna layers 210 may include an upper high-frequency antenna layer 210H and a lower high-frequency antenna layer 210L. The upper high-frequency antenna layer 210H may be located at the top of the antenna unit, and the lower high-frequency antenna layer 210L may be disposed between the upper high-frequency antenna layer 210H and the low-frequency antenna layer 212 in the vertical direction.

[0072] The plurality of high-frequency antenna layers 210 may radiate a signal having a frequency belonging to the millimeter wave (mmWave) frequency band.

[0073] The low-frequency antenna layer 212 serves to radiate a low-frequency signal (or LB signal) in a second radio frequency band lower than the first radio frequency band.

[0074] The transmission line disposed in the antenna unit ANT may include a capacitive power feeding unit 310 and an upper via VAU.

[0075] The capacitive power feeding unit 310 is disposed opposite each of the plurality of high-frequency antenna layers 210 and the low-frequency antenna layer 212 in the vertical direction with the antenna insulating layer interposed therebetween.

[0076] According to the embodiment, the plurality of high-frequency antenna layers 210, i.e., the upper high-frequency antenna layer 210H and the lower high-frequency antenna layer 210L, may be disposed above the capacitive power feeding unit 310, and the low-frequency antenna layer 212 may be disposed below the capacitive power feeding unit 310. The lower high-frequency antenna layer 210L may be disposed between the upper high-frequency antenna layer 210H and the capacitive power feeding unit 310 in the vertical direction.

[0077] In this case, the upper via VAU serves to interconnect the capacitive power feeding unit 310 and the lower high-frequency antenna layer 210L. Therefore, according to the embodiment, the capacitive power feeding unit 310 may directly feed power to the lower high-frequency antenna layer 210L through the upper via VAU.

[0078] In general, a capacitor is a device in which carriers move between two metal plates opposing each other with a dielectric material interposed therebetween. Using this principle, the capacitive power feeding unit 310 may feed power to the low-frequency antenna layer 212 in a capacitive manner with a dielectric material interposed therebetween. Using the same principle, the lower high-frequency antenna layer 210L may feed power to the upper high-frequency antenna layer 210H in a capacitive manner.

[0079] The capacitive power feeding unit 310 is electrically connected to the lower high-frequency antenna layer 210L via the upper via VAU. However, the capacitive power feeding unit 310 is not in physical contact with the low-frequency antenna layer 212, but is spaced apart from the low-frequency antenna layer 212 with a dielectric material interposed therebetween, as described above. In addition, the upper high-frequency antenna layer 210H is not in physical contact with the lower high-frequency antenna layer 210L, but is spaced apart from the lower high-frequency antenna layer 210L with a dielectric material interposed therebetween, as described above.

[0080] In addition, the transmission line may further include another via 220.

[0081] The other via 220 may be directly connected to the capacitive power feeding unit 310 and may be connected to a port through the transmission line disposed in the routing unit ROT via the core unit CO. In this case, the other via 220 connected to the port may pass through the low-frequency antenna layer 212 to be connected to the capacitive power feeding unit 310. The low-frequency antenna layer 212 may include therein a through-hole TH through which the other via 220 passes.

[0082] The material of each of the upper via VAU and the other via 220 may be identical to the material of the first to Mthantenna layers AL1 to ALM and the first to Nthrouting layers RL1 to RLN. For example, the material of each of the upper via VAU and the other via 220 may include metal, such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb), titanium (Ti), or alloys thereof. However, the embodiments are not limited thereto.

[0083] According to the embodiment, the diameter of the through-hole TH may be larger than the diameter of the other via 220. The reason for this is to prevent the other via 220 passing through the through-hole TH from contacting the low-frequency antenna layer 212.

[0084] In some cases, a ring RI (or via connection part) may be disposed on a portion of the outer surface of the other via 220 that is located in the through-hole TH in order to efficiently connect the other via 220 disposed in each insulating layer to the other via 220 disposed in another insulating layer. In addition, because the ring RI has a larger planar area than the other via 220, the ring RI may perform a role similar to that of the capacitive power feeding unit 310 of the high-frequency antenna layer 210 and the low-frequency antenna layer 212.

[0085] The upper high-frequency antenna layer 210H and the lower high-frequency antenna layer 210L described above may correspond to the first antenna layer AL1 and the second antenna layer AL2 shown in FIG. 3, respectively, and the low-frequency antenna layer 212 may correspond to the third antenna layer AL3 shown in FIG. 3. Therefore, the capacitive power feeding unit 310 may be disposed between the second antenna layer AL2 and the third antenna layer AL3 shown in FIG. 3.

[0086] Hereinafter, an antenna unit according to an embodiment connected to two ports Port1 and Port2 will be described with reference to FIG. 5.

[0087] FIG. 5 is a perspective view of the antenna substrate according to the embodiment, FIG. 6A is a cross-sectional view of the antenna substrate shown in FIG. 5, and FIG. 6B is a plan view of the antenna substrate shown in FIG. 6A. For convenience of description, FIG. 6B shows only the first and second antenna layers 410 and 420 shown in FIG. 6A.

[0088] The antenna substrate shown in FIG. 5 may correspond to an embodiment of the antenna substrate shown in FIG. 4.

[0089] The antenna substrate may include first to fifth antenna layers 410, 420, 430, 440, and 450 and a ground layer 460, which are stacked so as to be spaced apart from each other in the vertical direction, and may include an upper via 320, a lower via 330, a via connection part VC, a main via MVA, and a capacitive power feeding unit 310A. Here, the ground layer 460 may correspond to the first routing layer RL1 shown in FIG. 3.

[0090] In addition, the first antenna layer 410 may correspond to the upper high-frequency antenna layer 210H shown in FIG. 4, and the second antenna layer 420 may correspond to the lower high-frequency antenna layer 210L shown in FIG. 4.

[0091] The first antenna layer 410 may include a first central portion 412 and a plurality of peripheral portions 414. Here, the peripheral portion may mean a parasitic patch or a stack patch.

[0092] The plurality of peripheral portions 414 may be disposed around the first central portion 412 so as to be spaced apart from the first central portion 412 by a predetermined gap in the horizontal direction. For example, as illustrated in FIG. 6B, the plurality of peripheral portions 414 may include first to fourth peripheral portions 414A, 414B, 414C, and 414D. The first peripheral portion 414A may be disposed near the first central portion 412 so as to be spaced apart from the first central portion 412 by a first gap Y1 in the second direction, which is the horizontal direction. The third peripheral portion 414C may be disposed near the first central portion 412 so as to be spaced apart from the first central portion 412 by a second gap Y2 in the second direction, which is the horizontal direction. Similar thereto, each of the second and fourth peripheral portions 414B and 414D may also be disposed near the first central portion 412. The peripheral portions serve to match impedance and further extend the bandwidth.

[0093] The second antenna layer 420 includes only a second central portion without including a peripheral portion.

[0094] According to the embodiment, the lower high-frequency antenna layer 210L may have a larger planar area than the upper high-frequency antenna layer 210H. For example, assuming that each of the first antenna layer 410 and the second antenna layer 420 has a square planar shape, if the length of one side of the first antenna layer 410 is 0.5λ1 and the length of one side of the second antenna layer 420 is 0.5λ2, λ2 may be greater than λ1.

[0095] In addition, according to the embodiment, as shown in FIG. 6A, a first edge 420E1 of the second antenna layer (i.e., the second central portion) 420 may overlap the first gap Y1 in the vertical direction, and a second edge 420E2 of the second antenna layer 420 may overlap the second gap Y2 in the vertical direction.

[0096] In addition, according to the embodiment, as shown in FIG. 6B, because the second central portion 420 is larger than the first central portion 412, the entirety of the first central portion 412 may overlap the second central portion 420 in the vertical direction.

[0097] The third antenna layer 430 shown in FIGs. 5 and 6A may correspond to the low-frequency antenna layer 212 shown in FIG. 4.

[0098] At least one antenna layer may be additionally disposed between the third antenna layer 430 and the ground layer 460. For example, as shown in FIG. 5, a plurality of fourth and fifth antenna layers 440 and 450 may be additionally disposed between the third antenna layer 430 and the ground layer 460.

[0099] Each of the plurality of fourth and fifth antenna layers 440 and 450 may be omitted or may be added in order to perform various roles, such as impedance matching, bandwidth adjustment, or S-parameter tuning. The embodiments are not limited as to the presence or absence of the additional antenna layers 440 and 450 or the number thereof.

[0100] The upper via 320 may correspond to an embodiment of the upper via VAU shown in FIG. 4. The lower via 330, the via connection part VC, and the main via MVA may correspond to embodiments of the other via 220 shown in FIG. 4. The capacitive power feeding unit 310A may correspond to an embodiment of the capacitive power feeding unit 310 shown in FIG. 4.

[0101] That is, the transmission line according to the embodiment may include the vias 320, 330, and MVA, the via connection part VC, and the capacitive power feeding unit 310A.

[0102] Hereinafter, an embodiment of the transmission line will be described with reference to the accompanying drawings. The following description of the transmission line may be applicable regardless of the presence or absence of the additional antenna layers 440 and 450 or the number thereof.

[0103] The capacitive power feeding unit 310A may include first and second power feeding plates 312 and 314.

[0104] Hereinafter, various embodiments of the first and second power feeding plates 312 and 314 shown in FIG. 5 will be described with reference to FIGs. 7A and 7B.

[0105] FIGs. 7A and 7B are plan views of embodiments of the first and second power feeding plates 312 and 314 shown in FIG. 5. Although not visible in FIGs. 7A and 7B, lower vias 332 and 334 are indicated by dotted lines in order to aid in understanding of the embodiments.

[0106] Here, CP is defined as a point at which an axis passing through the center of the second antenna layer 420 in the vertical direction meets a virtual horizontal plane on which the first and second power feeding plates 312 and 314 are disposed, and is referred to as a center point.

[0107] According to the embodiment, as illustrated in FIGs. 7A and 7B, first power feeding plates 312A and 312B may be located on a virtual first horizontal line HL1 passing through the center point CP, and second power feeding plates 314A and 314B may be located on a virtual second horizontal line HL2 passing through the center point CP and orthogonal to the first horizontal line HL1. In this way, the first power feeding plates 312A and 312B and the second power feeding plates 314A and 314B may be disposed orthogonal to each other with respect to the center point CP.

[0108] In addition, the first power feeding plates 312A and 312B and the second power feeding plates 314A and 314B may be disposed so as not to be symmetrical to each other with respect to the center point CP.

[0109] In addition, the first power feeding plates 312A and 312B and the second power feeding plates 314A and 314B may be disposed at a predetermined angle, e.g., 90°, 60°, 45°, or 30°, relative to each other with respect to the center point CP. That is, an angle θ formed by the first horizontal line HL1 and the second horizontal line HL2 may be, for example, 90°, 60°, 45°, or 30°.

[0110] Each of the first and second power feeding plates 312 and 314 may have any of various planar shapes.

[0111] According to one embodiment, the first and second power feeding plates may have a circular or polygonal planar shape.

[0112] According to another embodiment, each of the first and second power feeding plates may have a tapered planar shape having a region that gradually increases in width in a direction away from the center point CP, i.e., gradually decreases in width in a direction approaching the center point CP. Alternatively, each of the first and second power feeding plates may have a region that gradually increases in width and then gradually decreases in width in a direction away from the center point CP. In this case, the region that decreases in width may have a curvature.

[0113] For example, as shown in FIG. 7A, each of the first and second power feeding plates 312A and 314A may have a water drop-shaped plane. Alternatively, as shown in FIG. 7B, each of the first and second power feeding plates 312B and 314B may have a planar shape in which a portion located farthest from the center point CP is cut out from the water drop-shaped plane shown in FIG. 7A or may have a trapezoidal planar shape.

[0114] Referring to FIGs. 7A and 7B, it may be seen that the planar area of each of the first power feeding plates 312A and 312B and the second power feeding plates 314A and 314B is larger than the planar area of the upper via 320 or the lower via 330.

[0115] The upper via 320 electrically connects the capacitive power feeding unit 310A to the second antenna layer 420. For example, the upper via 320 may include an end connected to the capacitive power feeding unit 310A and another end connected to the second antenna layer 420.

[0116] The upper via 320 may include first and second upper vias 322 and 324. The first upper via 322 may include an end connected to one side of the upper surface of the first power feeding plate 312 and another end connected to the second antenna layer 420. The second upper via 324 may include an end connected to one side of the upper surface of the second power feeding plate 314 and another end connected to the second antenna layer 420.

[0117] The lower via 330 may include an end connected to the capacitive power feeding unit 310A and another end connected to the via connection part VC.

[0118] The lower via 330 may include first and second lower vias 332 and 334. The first lower via 332 may include an end connected to the other side of the lower surface of the first power feeding plate 312 and another end connected to the via connection part VC. The second lower via 334 may include an end connected to the other side of the lower surface of the second power feeding plate 314 and another end connected to the via connection part VC.

[0119] The first power feeding plate 312 may extend in the horizontal direction from one end of the first lower via 332 such that the upper side thereof faces the second antenna layer 420 and the lower side thereof faces the third antenna layer 430. The second power feeding plate 314 may extend in the horizontal direction from one end of the second lower via 334 such that the upper side thereof faces the second antenna layer 420 and the lower side thereof faces the third antenna layer 430, and may be disposed so as to be spaced apart from the first power feeding plate 312.

[0120] Referring to FIGs. 7A and 7B, one side of the upper surface of each of the first power feeding plates 312A and 312B on which one end of the first upper via 322 is disposed and the other side of the lower surface of each of the first power feeding plates 312A and 312B on which one end of the first lower via 332 is disposed may not overlap each other in the vertical direction.

[0121] In addition, one side of the upper surface of each of the second power feeding plates 314A and 314B on which one end of the second upper via 324 is disposed and the other side of the lower surface of each of the second power feeding plates 314A and 314B on which one end of the second lower via 334 is disposed may not overlap each other in the vertical direction.

[0122] According to the embodiment, a distance d1 between the first lower via 332 and the center point CP shown in FIG. 7A may be equal to a distance d2 between the second lower via 334 and the center point CP, and a distance d3 between the first lower via 332 and the center point CP shown in FIG. 7B may be equal to a distance d4 between the second lower via 334 and the center point CP.

[0123] The main via MVA may include an end portion connected to the via connection part VC through the third antenna layer 430 corresponding to a low-frequency antenna layer. The main via MVA may include first and second main vias VA1 and VA2 extending from the ground layer 460 and passing through the third to fifth antenna layers 430, 440, and 450. The first and second main vias VA1 and VA2 may pass through the plurality of antenna layers 430, 440, and 450 to be connected to the ground layer 460. To this end, similar to the low-frequency antenna layer 212 including therein the through-hole TH shown in FIG. 4, each of the third to fifth antenna layers 430, 440, and 450 may include therein through-holes through which the first and second main vias VA1 and VA2 pass.

[0124] One of both end portions of the first main via VA1 may be connected to the first via connection part VC1, and the other thereof may be connected to a first port Port1 via the ground layer 460. One of both end portions of the second main via VA2 may be connected to the second via connection part VC2, and the other thereof may be connected to a second port Port2 via the ground layer 460.

[0125] The via connection part VC serves to connect the lower via 330 to the main via MVA. That is, one end of the via connection part VC may be connected to the other end of the lower via 330, and the other end of the via connection part VC may be connected to one end portion of the main via MVA.

[0126] The via connection part VC may include first and second via connection parts VC1 and VC2. The first via connection part VC1 may connect the other end of the first lower via 332 to one end portion of the first main via VA1, and the second via connection part VC2 may connect the other end of the second lower via 334 to one end portion of the second main via VA2.

[0127] Generally, the third antenna layer 430, which is a low-frequency antenna layer, has a smaller area than the second antenna layer 420, which is a high-frequency antenna layer. Thus, if the capacitive power feeding unit 310A is located below the second antenna layer 420, it may be difficult to connect the main via MVA to the capacitive power feeding unit 310A. Therefore, the main via MVA may be connected to the capacitive power feeding unit 310A via the via connection part VC.

[0128] Hereinafter, an antenna substrate according to a comparative example and the antenna substrate according to the embodiment will be described with reference to the accompanying drawings.

[0129] FIG. 8 is a cross-sectional view of an antenna substrate according to a comparative example.

[0130] The antenna substrate shown in FIG. 8 includes first to seventh antenna layers 10 to 22, first to fourth vias 42 to 48, and a ground layer 24.

[0131] The second and sixth antenna layers 12 and 20 perform the same role as the first and third antenna layers 420 and 430 shown in FIG. 5, respectively, and the ground layer 24 corresponds to the ground layer 460 shown in FIG. 5. Thus, a duplicate description thereof will be omitted.

[0132] The first antenna layer 10 corresponds to a high-frequency stack patch, the third antenna layer 14 corresponds to a high-frequency feeding patch, the fourth antenna layer 16 corresponds to a high-frequency impedance matching patch, the fifth antenna layer 18 corresponds to a low-frequency stack patch, and the seventh antenna layer 22 corresponds to a low-frequency impedance matching patch.

[0133] Ends of the first and second vias 42 and 44 are directly coupled to the sixth antenna layer 20 in order to feed power to the sixth antenna layer 20. In addition to the first and second vias 42 and 44, ends of the third and fourth vias 46 and 48 are directly coupled to the second antenna layer 12 in order to feed power to the second antenna layer 12.

[0134] In this way, according to the comparative example, a total of four vias 42 to 48 is required to feed power to the second and sixth antenna layers 12 and 20, and each of the four vias 42 to 48 is directly coupled to the antenna layer corresponding thereto.

[0135] In contrast, according to the embodiment, as shown in FIG. 5, the second antenna layer 420 may receive power from a total of two vias, i.e., the first and second main vias VA1 and VA2, via the via connection part VC, the lower via 330, the power feeding unit 310A, and the upper via 320. The first antenna layer 410 may receive power from the second antenna layer 420 or the power feeding unit 310A in a capacitive manner without being directly coupled to the second antenna layer 420 or the power feeding unit 310A. The third antenna layer 430 may receive power from the second antenna layer 420 or the power feeding unit 310A in a capacitive manner.

[0136] Therefore, according to the embodiment, a smaller number of vias than in the comparative example is used to feed power to the high-frequency antenna layers 410 and 420 and the low-frequency antenna layer 430. Accordingly, the antenna substrate according to the embodiment may have simple configuration, may reduce manufacturing costs, and may simplify a manufacturing process. Further, because the lengths thereof in the first, second, and third directions are reduced, the antenna substrate according to the embodiment may have a smaller size and volume than the comparative example.

[0137] Hereinafter, the area of a region of each antenna layer to which power is fed will be referred to as a “power-feeding area”. In the case of the comparative example, because the high-frequency antenna layer 12 and the low-frequency antenna layer 20 receive power from the vias 42 to 48, the area of a region of each of the high-frequency antenna layer 12 and the low-frequency antenna layer 20 that is in contact with a corresponding one of the vias 42 to 48, i.e., the planar area of each of the vias 42 to 48, corresponds to the power-feeding area.

[0138] According to the embodiment, because the first antenna layer 410 receives power from the second antenna layer 420 in a capacitive manner, the entire planar area of the second antenna layer 420 corresponds to the power-feeding area. Further, because the low-frequency antenna layer 430 receives power from the capacitive power feeding unit 310A, the entire planar area of the capacitive power feeding unit 310A corresponds to the power-feeding area. In this case, the planar area of the second antenna layer 420 is larger than the planar areas of the vias 42 to 48, and the planar area of the capacitive power feeding unit 310A is larger than the planar areas of the vias 42 to 48.

[0139] In this way, the power-feeding area of the embodiment is larger than that of the comparative example. Accordingly, a current to be fed may flow through various paths, and thus the bandwidth may increase, with a result that the embodiment may be applied to a global network.

[0140] FIG. 9 is a graph indicating return loss (or reflection coefficient) for the antenna substrate according to the comparative example, and FIG. 10 is a graph indicating return loss for the antenna substrate according to the embodiment. In each of FIGs. 9 and 10, the horizontal axis represents a frequency, and the vertical axis represents return loss. Return loss is a ratio of reflected voltage to input voltage.

[0141] If the antenna substrate according to the comparative example is implemented in the configuration shown in FIG. 8 and a first height H1 in the vertical direction from the ground layer 24 to the fifth antenna layer 18 is 0.36 mm, the return loss characteristics for first to fourth ports Port1, Port2, Port3, and Port4 connected to the first to fourth vias 42 to 48, respectively, are obtained as shown in FIG. 9.

[0142] In the case of the embodiment, as shown in FIG. 5, two high-frequency antenna layers 410 and 420 are disposed above the capacitive power feeding unit 310A, i.e., the first antenna layer 410 corresponding to an upper high-frequency antenna layer is additionally disposed above the second antenna layer 420 corresponding to a lower high-frequency antenna layer. Therefore, the embodiment may have a second bandwidth BW2, which is wider than a first bandwidth BW1, in a high-frequency band. Accordingly, it may be seen that the embodiment has a wide bandwidth of 37 GHz to 43.5 GHz at -10 dB and covers a wider operating frequency band at -6 dB.

[0143] λ1 and λ2 are wavelengths of 37 GHz and 43.5 GHz band frequencies in the second bandwidth BW2, respectively, and may be adjusted for formation of multiple resonant modes by the capacitive power feeding unit 310 located below the first and second antenna layers 410 and 420.

[0144] In addition, the embodiment may achieve miniaturization by overlapping the high-frequency antenna layers in the vertical direction while minimizing degradation in performance thereof.

[0145] Hereinafter, a front end module according to an embodiment will be described with reference to the accompanying drawings.

[0146] FIG. 11 is a block diagram of a front end module 500 according to an embodiment.

[0147] The front end module 500 according to the embodiment shown in FIG. 11 may include an antenna 510, first and second amplifiers 520 and 540, a multilayer filter 530, and a switch 550.

[0148] The first amplifier 520 may amplify a signal received through the antenna 510 and may provide a result of amplification to the multilayer filter 530. For example, the first amplifier 520 may be a low noise amplifier (LNA).

[0149] The multilayer filter 530 may filter the signal amplified by the first amplifier 520 and may output the filtered signal through an output terminal OUT.

[0150] The second amplifier 540 may amplify a signal input through an input terminal IN and may transmit a result of amplification through the antenna 510. For example, the second amplifier 540 may be a power amplifier (PA).

[0151] The switch 550 may be disposed between the antenna 510 and each of the input terminal of the first amplifier 520 and the output terminal of the second amplifier 540 to select signal paths therebetween.

[0152] The antenna 510 may correspond to the antenna substrate 100 according to the above-described embodiment, and thus a duplicate description thereof will be omitted.

[0153] The configuration shown in FIG. 11 is merely illustrative of an embodiment of the front end module 500, and the antenna substrate 100 according to the above-described embodiment may be employed as a substrate for a front end module having various configurations without being limited to the configuration shown in FIG. 11.

[0154] The antenna substrate and the front end module according to the above-described embodiments may be applied to modules for mobile devices, base stations, repeaters, etc. to enable short- or medium-range ultra-high-speed broadband communication for mobile devices and mobility devices. However, the embodiments are not limited to any specific application.

[0155] While the present disclosure has been particularly shown and described with reference to exemplary embodiments thereof, these embodiments are only proposed for illustrative purposes, and do not restrict the present disclosure, and it will be apparent to those skilled in the art that various changes in form and detail may be made without departing from the essential characteristics of the embodiments set forth herein. For example, respective configurations set forth in the embodiments may be modified and applied. Further, differences in such modifications and applications should be construed as falling within the scope of the present disclosure as defined by the appended claims.

[0156] Various embodiments have been described in the best mode for carrying out the invention.

[0157] The antenna substrate and front end module including the same according to the embodiment may be applied to the mobile communication system.

Claims

1.An antenna substrate, comprising:a plurality of antenna layers stacked so as to be spaced apart from each other in a vertical direction;an antenna insulating layer disposed between the plurality of antenna layers; anda transmission line including a capacitive power feeding unit disposed so as to oppose the plurality of antenna layers with the antenna insulating layer interposed therebetween,wherein the plurality of antenna layers includes:a plurality of high-frequency antenna layers disposed above the capacitive power feeding unit so as to be stacked in the vertical direction, the plurality of high-frequency antenna layers being configured to radiate a high-frequency signal in a first radio frequency band; anda low-frequency antenna layer disposed below the capacitive power feeding unit, the low-frequency antenna layer being configured to radiate a low-frequency signal in a second radio frequency band lower than the first radio frequency band.2.The antenna substrate according to claim 1, wherein the plurality of high-frequency antenna layers includes:an upper high-frequency antenna layer; anda lower high-frequency antenna layer disposed between the upper high-frequency antenna layer and the capacitive power feeding unit in the vertical direction.3.The antenna substrate according to claim 2, wherein the transmission line further includes an upper via configured to connect the capacitive power feeding unit to the lower high-frequency antenna layer.4.The antenna substrate according to claim 3, wherein the transmission line further includes:a main via including an end portion passing through the low-frequency antenna layer;a lower via including an end connected to the capacitive power feeding unit; anda via connection part configured to connect another end of the lower via to the end portion of the main via.5.The antenna substrate according to claim 2, wherein the lower high-frequency antenna layer has a larger planar area than the upper high-frequency antenna layer.6.The antenna substrate according to claim 5, wherein the upper high-frequency antenna layer includes:a first central portion; anda plurality of peripheral portions disposed around the first central portion so as to be spaced apart from the first central portion by a predetermined gap in a horizontal direction.7.The antenna substrate according to claim 6, wherein the lower high-frequency antenna layer includes a second central portion.8.The antenna substrate according to claim 7, wherein the second central portion includes an edge overlapping the gap in the vertical direction.9.The antenna substrate according to claim 7, wherein an entirety of the first central portion overlaps the second central portion in the vertical direction.10.A front end module, comprising:a plurality of antenna areas spaced apart from each other in a horizontal direction,wherein each of the plurality of antenna areas includes an antenna unit,wherein the antenna unit includes:a plurality of antenna layers stacked so as to be spaced apart from each other in a vertical direction;an antenna insulating layer disposed between the plurality of antenna layers; anda transmission line including a capacitive power feeding unit configured to feed power to the plurality of antenna layers in a capacitive manner with the antenna insulating layer interposed therebetween, andwherein the plurality of antenna layers includes:a plurality of high-frequency antenna layers disposed above the capacitive power feeding unit so as to be stacked in the vertical direction, the plurality of high-frequency antenna layers being configured to radiate a high-frequency signal in a first radio frequency band; anda low-frequency antenna layer disposed below the capacitive power feeding unit, the low-frequency antenna layer being configured to radiate a low-frequency signal in a second radio frequency band lower than the first radio frequency band.

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