Antenna module and sub-module

Abstract

The present invention achieves an antenna module and a sub-module capable of suppressing deterioration in the quality of an RF signal in a configuration in which a plurality of sub-modules are disposed on a main substrate. This antenna module (100) comprises: a plurality of sub-modules (200) in which a plurality of antenna elements are two-dimensionally arranged side by side in a first direction Dx and a second direction Dy intersecting the first direction Dx; a main substrate (140) in which the plurality of sub-modules (200) are two-dimensionally arranged side by side in the first direction Dx and the second direction Dy, respectively; and a first terminal (141A) and a second terminal (141B) that electrically connect the sub-modules (200) and the main substrate (140). The first terminal (141A) is provided in one of four regions obtained by dividing the sub-module (200) into two in each of the first direction Dx and the second direction Dy. The second terminal (141B) is provided, among the four regions, in a region different from the region in which the first terminal (141A) is provided.

Description

Antenna Module and Sub-Module

[0001] The present disclosure relates to an antenna module and a sub-module.

[0002] For example, Patent Document 1 below discloses an antenna module in which four sub-modules each provided with 4×4 antenna elements are combined to form an 8×8 two-dimensional array. In Patent Document 1 below, a BFIC having a beamforming function is provided on the back surface of a substrate on which a plurality of antenna elements are provided for each sub-module.

[0003] International Publication No. 2020 / 100464

[0004] [[ID=1,2]]

[0005] The present disclosure has been made in view of the above, and an object thereof is to realize an antenna module and a sub-module that can suppress a decrease in RF signal quality in a configuration in which a plurality of sub-modules are arranged on a main board.

[0006] ​An antenna module according to one aspect of the present disclosure comprises a plurality of submodules in which a plurality of antenna elements are arranged in a two-dimensional manner in a first direction and a second direction intersecting the first direction; a main board on which the plurality of submodules are arranged in a two-dimensional manner in the first direction and the second direction, respectively; and a first terminal and a second terminal that electrically connect the submodules and the main board, wherein the first terminal is provided in one of four regions obtained by dividing the submodule into two in the first direction and the second direction, respectively, and the second terminal is provided in a region of the four regions different from the region in which the first terminal is provided.

[0007] A submodule of one aspect of this disclosure is a submodule used in the antenna module, wherein the mixer terminal of the BFIC is electrically connected to the first terminal and the second terminal.

[0008] A submodule of one aspect of the present disclosure is a submodule used in the antenna module, wherein the BFIC comprises a first BFIC and a second BFIC different from the first BFIC, and the mixer terminals of the first BFIC and the mixer terminals of the second BFIC are electrically connected to the first terminal and the second terminal.

[0009] According to this disclosure, in a configuration in which multiple submodules are arranged on a main board, it is possible to realize an antenna module and submodules that can suppress the degradation of RF signal quality.

[0010] Figure 1 is a plan view showing an example of an antenna array. Figure 2 is a block diagram showing the configuration of the BFIC. Figure 3 is a schematic diagram showing an example of an antenna module according to Embodiment 1. Figure 4 is a cross-sectional view taken along line IV-IV' of Figure 3. Figure 5 is a plan view showing the relationship between the submodule and the position of the terminals. Figure 6 is a schematic diagram showing an example of an antenna module according to a first modification of Embodiment 1. Figure 7 is a schematic diagram showing an example of an antenna module according to a second modification of Embodiment 1. Figure 8 is a diagram showing an example of the configuration of a submodule according to Embodiment 2. Figure 9 is a diagram showing a first example of the configuration of a submodule according to Embodiment 3. Figure 10 is a diagram showing a second example of the configuration of a submodule according to Embodiment 3. Figure 11 is a diagram showing a first example of a hybrid circuit. Figure 12 is a diagram showing a second example of a hybrid circuit.

[0011] The antenna module and submodule according to the embodiment will be described in detail below with reference to the drawings. However, the present invention is not limited by this embodiment. Furthermore, the components of each embodiment include those that are easily substituted or substantially identical to those that are substituted by those skilled in the art. Each embodiment is illustrative, and partial substitution or combination of the configurations shown in different embodiments is possible. From Embodiment 2 onward, descriptions of matters common to Embodiment 1 will be omitted, and only the differences will be described. In particular, similar effects and benefits due to similar configurations will not be mentioned sequentially for each embodiment.

[0012] (Embodiment 1) Figure 1 is a plan view showing an example of an antenna array. As shown in Figure 1, the antenna array 120 has a plurality of antenna elements 121 provided on a substrate. In this disclosure, the antenna elements 121 are patch antennas having a rectangular flat plate shape. The plurality of antenna elements 121 are arranged in a two-dimensional manner on the substrate 122 in a substantially square shape when viewed from above.

[0013] More specifically, the multiple antenna elements 121 are arranged in a first direction Dx and a second direction Dy in a plan view. In other words, the first direction Dx and the second direction Dy indicate the direction in which the multiple antenna elements 121 are arranged. The first direction Dx and the second direction Dy are intersecting directions. The example shown in Figure 1 illustrates a configuration in which the first direction Dx and the second direction Dy are orthogonal. In the example shown in Figure 1, the third direction Dz is a direction orthogonal to the first direction Dx and the second direction Dy.

[0014] As the substrate 122, for example, a ceramic multilayer substrate is used. As the ceramic multilayer substrate, for example, a low-temperature co-fired ceramic multilayer substrate (LTCC (Low Temperature Co-fired Ceramics) multilayer substrate) is used. The substrate 122 may also be a multilayer resin substrate formed by laminating multiple resin layers made of resins such as epoxy and polyimide. Furthermore, the substrate 122 may be a multilayer resin substrate formed by laminating multiple resin layers made of liquid crystal polymer (LCP) having a low dielectric constant, or a multilayer resin substrate formed by laminating multiple resin layers made of fluororesin, or a ceramic multilayer substrate sintered at a higher temperature than LTCC.

[0015] Figure 2 is a block diagram showing the configuration of a BFIC. In the example shown in Figure 2, one BFIC (BeamFormer Integrated Circuit) is provided for a region 123 containing four 2x2 antenna elements 121 of the antenna array 120 shown in Figure 1, illustrating a configuration in which four BFICs are provided corresponding to one antenna array 120. The number of antenna elements 121 included in region 123 and the number of BFICs provided in one antenna array 120 are not limited to the configurations shown in Figures 1 and 2.

[0016] The BFIC110 comprises switches 111A, 111B, 111C, 111D, 113A, 113B, 113C, 113D, and 117; power amplifiers 112AT, 112BT, 112CT, and 112DT; low-noise amplifiers 112AR, 112BR, 112CR, and 112DR; attenuators 114A, 114B, 114C, and 114D; digital phase shifters 115A, 115B, 115C, and 115D; a signal combiner / demultiplexer 116; and an amplification circuit 119.

[0017] When transmitting the RF signal TX, switches 111A, 111B, 111C, 111D, 113A, 113B, 113C, and 113D are switched to the power amplifiers 112AT, 112BT, 112CT, and 112DT. Switch 117 is connected to the transmitting amplifier of the amplification circuit 119.

[0018] The RF signal TX is amplified by the amplification circuit 119. The amplified RF signal TX is then split into four parts by the signal combiner / demultiplexer 116 and passes through four signal paths to feed power to different antenna elements 121. At this time, the directivity of the antenna array 120 can be adjusted by individually adjusting the phase values ​​of the digital phase shifters 115A, 115B, 115C, and 115D located in each signal path.

[0019] When receiving the RF signal RX, switches 111A, 111B, 111C, 111D, 113A, 113B, 113C, and 113D are switched to the low-noise amplifiers 112AR, 112BR, 112CR, and 112DR. Switch 117 is connected to the receiving amplifier of the amplification circuit 119.

[0020] The RF signal RX received by each antenna element 121 passes through four different signal paths, is combined by the signal combiner / demultiplexer 116, and is amplified by the amplification circuit 119.

[0021] The BFIC 110 further includes a scanning control circuit 130. The scanning control circuit 130 is a circuit that controls the beam direction Db during transmission and the beam direction Db during reception. The scanning control circuit 130 includes a beam direction control circuit 131 and a phase control circuit 132. The beam direction control circuit 131 outputs a control signal based on the beam direction Db during transmission or the beam direction Db during reception to the phase control circuit 132. Based on the control signal from the beam direction control circuit 131, the phase control circuit 132 calculates the phase of the signal propagating through each antenna element 121 and outputs it to digital phase shifters 115A, 115B, 115C, and 115D.

[0022] The digital phase shifters 115A, 115B, 115C, and 115D change the phase of the signal propagating through each antenna element 121 based on the output of the phase control circuit 132.

[0023] The BFIC 110 is formed, for example, as a single-chip integrated circuit component including the above circuit configuration. Alternatively, the equipment corresponding to each antenna element 121 in the BFIC 110 (switch, power amplifier, low-noise amplifier, attenuator, digital phase shifter) may be formed as a single-chip integrated circuit component for each corresponding antenna element 121. Furthermore, the scanning control circuit 130 is not limited to being provided on the BFIC 110, and may be provided, for example, outside the BFIC 110.

[0024] Figure 3 is a schematic diagram showing an example of an antenna module according to Embodiment 1. Figure 4 is a cross-sectional view taken along line IV-IV' in Figure 3. In the configuration shown in Figures 3 and 4, the antenna module 100 is constructed by arranging a plurality of submodules 200, each having a BFIC 110 on the second main surface 122b of a substrate 122 constituting the antenna array 120, in a two-dimensional arrangement on a main substrate 140. Figures 3 and 4 illustrate an example in which one BFIC 110 is provided for the antenna array 120.

[0025] Multiple antenna elements 121 are provided on the first main surface 122a side of the substrate 122. Figure 4 illustrates an embodiment in which multiple antenna elements 121 are provided on the inner layer of the substrate 122. However, the embodiment is not limited to this, and multiple antenna elements 121 may also be provided on the surface layer of the first main surface 122a of the substrate 122, with a protective layer covering the multiple antenna elements 121.

[0026] The main substrate 140 is assumed to be a general-purpose multilayer board (MLB) composed of a different substrate than the substrate 122. The main substrate 140 is, for example, a general-purpose printed circuit board and has a greater signal transmission loss than the substrate 122, which is composed of a ceramic multilayer substrate.

[0027] Furthermore, in this disclosure, a mixer IC 142 is provided on the main board 140. The mixer IC 142 performs upconversion of the RF signal TX and downconversion of the RF signal RX.

[0028] This disclosure assumes a configuration in which one mixer IC 142 is provided for multiple submodules 200. Figures 3 and 4 illustrate an example in which four 2x2 submodules 200 are arranged in a two-dimensional array on a main board 140, and one mixer IC 142 is provided for these four submodules 200. The number of submodules 200 provided on the main board 140, and the number of submodules 200 corresponding to one mixer IC 142 on the main board 140, are not limited to the configurations shown in Figures 3 and 4.

[0029] As shown in Figure 4, the multiple submodules 200 are each arranged on top of the main board 140 in a third direction Dz. The multiple submodules 200 are electrically connected to the main board 140 via multiple terminals 141. Figures 3 and 4 illustrate an example in which two terminals 141 (141A, 141B) are provided. Figure 5 is a plan view showing the relationship between the submodules and the positions of the terminals. Hereinafter, terminal 141A will also be referred to as "first terminal 141A" and terminal 141B will also be referred to as "second terminal 141B".

[0030] As shown in Figure 5, each submodule 200 has a substantially square shape with two sides parallel to the first direction Dx and two sides parallel to the second direction Dy. The first terminal 141A is provided in one of the four regions obtained by dividing the submodule 200 into two equal parts in the first direction Dx and the second direction Dy, for example as shown in Figure 5. The second terminal 141B is provided in a region different from the region where the first terminal 141A is provided.

[0031] The number of terminals 141 corresponding to each submodule 200 is not limited to two. For example, there may be three or four terminals 141 corresponding to each submodule 200, each located in a different area.

[0032] In this disclosure, one of the multiple terminals 141 is used as the transmission path for the RF signals TX and RX. More specifically, if each submodule 200 has two terminals 141, a first terminal 141A and a second terminal 141B, then either the first terminal 141A or the second terminal 141B is used as the transmission path for the RF signals TX and RX. In other words, the BFIC 110 on each submodule 200 and the mixer IC 142 on the main board 140 are electrically connected via the first terminal 141A or the second terminal 141B. In Figure 3, the terminals 141 used as the transmission path for the RF signals TX and RX are hatched.

[0033] In the embodiments shown in Figures 3 and 4, the RF signals TX and RX of the right (upper right in Figure 3) submodule 200 are transmitted to the mixer IC 142 of the main board 140 via the first terminal 141A. This shortens the transmission path of the RF signals TX and RX on the main board 140, which has a greater signal transmission loss than the board 122.

[0034] Furthermore, in the embodiments shown in Figures 3 and 4, the RF signals TX and RX of the left (upper left in Figure 3) submodule 200 are transmitted to the mixer IC 142 of the main board 140 via the second terminal 141B. This shortens the transmission path for the RF signals TX and RX on the main board 140, which has a greater signal transmission loss than the board 122.

[0035] Furthermore, for transmission paths not used for transmitting RF signals TX and RX, termination circuits are provided at terminals 141 on the main board 140 (for example, the first terminal 141A located between the submodule 200 on the right in Figure 4 (upper right in Figure 3) and the main board 140, and the second terminal 141B located between the submodule 200 on the left in Figure 4 (upper left in Figure 3) and the main board 140). This configuration suppresses power leakage from terminals 141 not used for transmitting RF signals TX and RX to the main board 140.

[0036] Figure 6 is a schematic diagram showing an example of an antenna module according to a first modification of Embodiment 1. In the antenna module 100a shown in Figure 6, 16 submodules 200 are arranged in a 4x4 configuration on a main board 140, and one mixer IC 142 is provided corresponding to each of the 16 submodules 200, which are arranged in a 2x2 configuration.

[0037] Figure 7 is a schematic diagram showing an example of an antenna module according to a second modification of Embodiment 1. In the antenna module 100b shown in Figure 7, 16 submodules 200 are arranged in a 4x4 configuration on a main board 140, and one mixer IC 142 is provided corresponding to these 16 submodules 200.

[0038] In the first modified example shown in Figure 6 and the second modified example shown in Figure 7, similar to the embodiments shown in Figures 3 and 4, the RF signals TX and RX for each submodule 200 are transmitted via the terminal 141 closest to the mixer IC 142, among the two terminals 141 (first terminal 141A, second terminal 141B) provided corresponding to each submodule 200. This shortens the transmission path for the RF signals TX and RX on the main board 140, which has a greater signal transmission loss than the board 122. As a result, a decrease in RF signal quality (EIRP, EVM, received SNR, etc.) can be suppressed.

[0039] Furthermore, for transmission paths not used for transmitting RF signals TX and RX, termination circuits are provided at terminals 141 on the main board 140. This suppresses power leakage from terminals 141 not used for transmitting RF signals TX and RX to the main board 140. As a result, high-quality RF signal transmission can be achieved.

[0040] (Embodiment 2) Embodiment 2 describes the specific configuration of a submodule 200a provided with one BFIC 110. Figure 8 is a diagram showing an example of the configuration of a submodule according to Embodiment 2.

[0041] In the configuration example of the submodule 200a according to Embodiment 2 shown in Figure 8, the mixer terminal 151 of the BFIC 110 is electrically connected to the first terminal 141A and the second terminal 141B. More specifically, in a configuration having one BFIC 110, a Wilkinson divider 125 is provided in the transmission path 124 of the RF signals TX and RX between the mixer terminal 151 of the BFIC 110 and the first terminal 141A and the second terminal 141B. This ensures isolation of the RF signals TX and RX for each submodule 200a between the terminals of the mixer IC 142.

[0042] Furthermore, for transmission paths not used for RF signal TX and RX transmission, high-quality RF signal transmission can be achieved without necessarily providing a termination circuit at terminal 141 of the main board 140. This results in a highly versatile submodule 200a.

[0043] (Embodiment 3) In Embodiment 3, the specific configurations of submodules 200b and 200c, which are provided with two BFICs 110 (first BFIC 110A and second BFIC 110B), will be described. Figure 9 is a diagram showing a first example of the configuration of a submodule according to Embodiment 3. Figure 10 is a diagram showing a second example of the configuration of a submodule according to Embodiment 3.

[0044] In the first example of the configuration of the sub-module 200b according to Embodiment 3 shown in FIG. 9, in a configuration having two BFICs 110 (first BFIC 110A, second BFIC 110B), the transmission paths 124 of the RF signals TX and RX between the mixer terminals 151A of the first BFIC 110A and the mixer terminals 151B of the second BFIC 110B and the first terminal 141A and the second terminal 141B are configured such that two Wilkinson dividers 125a and 125b with their input and output terminals inverted are connected in series.

[0045] In the second example of the configuration of the sub-module 200c according to Embodiment 3 shown in FIG. 10, in a configuration having two BFICs 110 (first BFIC 110A, second BFIC 110B), a hybrid circuit 126 is provided in the transmission path 124 of the RF signals TX and RX between the mixer terminals 151A of the first BFIC 110A and the mixer terminals 151B of the second BFIC 110B and the first terminal 141A and the second terminal 141B.

[0046] FIG. 11 is a diagram showing a first example of the hybrid circuit. FIG. 12 is a diagram showing a second example of the hybrid circuit. Examples of the hybrid circuit 126 include distributed constant circuits (lines) such as the branch line coupler 126a shown in FIG. 11 and the rat-race circuit 126b shown in FIG. 12.

[0047] In the second example of the configuration of the sub-module 200c according to Embodiment 3 shown in FIG. 10, the A terminal of the branch line coupler 126a shown in FIG. 11 or the rat-race circuit 126b shown in FIG. 12 is connected to the first BFIC 110A.

[0048] Also, in the second example of the configuration of the sub-module 200c according to Embodiment 3 shown in FIG. 10, the B terminal of the branch line coupler 126a shown in FIG. 11 or the rat-race circuit 126b shown in FIG. 12 is connected to the first terminal 141A.

[0049] Also, in the second example of the configuration of the sub-module 200c according to Embodiment 3 shown in FIG. 10, the C terminal of the branch line coupler 126a shown in FIG. 11 or the rat-race circuit 126b shown in FIG. 12 is connected to the second BFIC 110B.

[0050] Furthermore, in the second example of the configuration of the submodule 200c according to Embodiment 3 shown in Figure 10, the second terminal 141B is connected to the D terminal of the branch line coupler 126a shown in Figure 11 or the rat race circuit 126b shown in Figure 12.

[0051] The first example of the configuration of submodule 200b according to Embodiment 3 shown in Figure 9, and the second example of the configuration of submodule 200c according to Embodiment 3 shown in Figure 10, allow for the isolation of RF signals TX and RX between the terminals of the mixer IC 142 for each submodule 200b and 200c, similar to Embodiment 2.

[0052] Furthermore, for transmission paths not used for RF signal TX and RX transmission, high-quality RF signal transmission can be achieved without necessarily providing a termination circuit at terminal 141 of the main board 140. This results in highly versatile submodules 200b and 200c.

[0053] The embodiments described above are provided to facilitate understanding of this disclosure and are not intended to limit the invention. This disclosure may be modified or improved without departing from its spirit, and equivalents thereof are included.

[0054] 100, 100a, 100b Antenna module 110 BFIC 110A First BFIC 110B Second BFIC 120 Antenna array 121 Antenna element 122 Substrate 123 Region 124 Transmission path 125, 125a, 125b Wilkinson divider 126 Hybrid circuit 126a Branch line coupler 126b Rat race circuit 140 Main board 141 Terminal 141A First terminal 141B Second terminal 151, 151A, 151B Mixer terminal 200, 200a, 200b, 200c Submodule

Claims

1. An antenna module comprising: a plurality of submodules, each having a plurality of antenna elements arranged in a two-dimensional array in a first direction and a second direction intersecting the first direction; a main board, each having the plurality of submodules arranged in a two-dimensional array in the first direction and the second direction; and a first terminal and a second terminal that electrically connect the submodules and the main board, wherein the first terminal is provided in one of four regions obtained by dividing the submodule into two in each of the first and second directions, and the second terminal is provided in a region of the four regions different from the region in which the first terminal is provided.

2. An antenna module according to claim 1, wherein the submodule comprises at least one BFIIC, and the main board comprises a mixer IC electrically connected to the BFIIC via the first terminal or the second terminal.

3. An antenna module according to claim 2, wherein the BFIC has a function of controlling the beam direction when transmitting and receiving RF signals.

4. An antenna module according to claim 2 or 3, wherein the main board comprises a circuit for terminating one of the first terminal and the second terminal.

5. A submodule used in the antenna module according to claim 2 or 3, wherein the mixer terminal of the BFIC is electrically connected to the first terminal and the second terminal.

6. A submodule according to claim 5, wherein a Wilkinson divider is provided in the signal transmission path between the mixer terminal of the BFIC and the first terminal and the second terminal.

7. A submodule used in the antenna module according to claim 2 or 3, wherein the BFIC comprises a first BFIC and a second BFIC different from the first BFIC, and the mixer terminals of the first BFIC and the mixer terminals of the second BFIC are electrically connected to the first terminal and the second terminal.

8. A submodule according to claim 7, wherein two Wilkinson dividers, with their input / output terminals inverted relative to each other, are connected in series to the signal transmission path between the mixer terminals of the first BFIC and the mixer terminals of the second BFIC and the first and second terminals.

9. A submodule according to claim 7, wherein a hybrid circuit is provided in the signal transmission path between the mixer terminal of the first BFIC and the mixer terminal of the second BFIC and the first terminal and the second terminal.

10. A submodule according to claim 9, wherein the hybrid circuit is a branch line coupler.

11. A submodule according to claim 9, wherein the hybrid circuit is a rat race circuit.

Images