WO2020200444A1

WO2020200444A1 - Partitioning of antenna device

Info

Publication number: WO2020200444A1
Application number: PCT/EP2019/058420
Authority: WO
Inventors: Ezio Perrone; Stefan Martens
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2019-04-03
Filing date: 2019-04-03
Publication date: 2020-10-08

Abstract

The present invention relates to a RFIC sub-module and an antenna device. The RFIC submodule comprises a RFIC die, and a first PCB comprising one or more connection elements provided on each of a top side and a bottom side of the first PCB, and one or more connection paths through the first PCB connecting the bottom side and the top side. Further, the RFIC die is attached to and electrically connected to one or more bottom side connection elements of the first PCB. The antenna device can comprise an antenna layer comprising at least one antenna module, a RFIC sub-module layer comprising at least one RFIC sub-module arranged below the antenna layer 201, wherein the RFIC sub-module layer is attached to and electrically connected to the antenna layer.

Description

PARTITIONING OF ANTENNA DEVICE

TECHNICAL FIELD

The present invention relates to the field of antennas, in particular to Antenna-on-Board (AoB) technology. The invention proposes a radio frequency integrated circuit (RFIC) sub-module for an antenna device. The invention also proposes the antenna device including an antenna layer and a RFIC sub-module layer arranged below the antenna layer.

BACKGROUND

The AoB technology, also called Antenna-in-Package (AiP) technology, combines antennas with radio dies into a surface mounted device (SMD). It represents an innovative and important development in the miniaturization of wireless communications systems in the recent years. Radio dies are particularly RFIC dies, including transceiver and receiver chips.

AoB technology has been proposed for different radio communication bands, e.g. the Ka-Band (28 GHz to 40 GHz) or the V-Band (60 GHz), as well as for gesture radars. It can provide effective antenna solutions to 5G and beyond, operating in the millimeter-wave bands and above.

In particular, the AoB technology adoption in 5G requires scalability to a high number of radio dies and antennas, a high level of integration between radio die and antennas in the AoB, as well as between the AoB and system Printed Circuit Board (PCB). Further, high reliability and low cost are needed.

Current solutions for AoB technology have limitations in material selections, as well as in the topology. For instance, in a PCB based AoB technology, expensive low-loss PCB materials (as well as a high layer count) have to be used for the complete stack-up. In addition, RFIC dies are mounted usually on an antenna PCB with flip chip balls. Thus, the biggest challenges of such example implementations are the high costs due to a high layer count, an expensive low- loss PCB material, and the thermal management of the RFIC dies. Another example is an embedded wafer level ball grid array (eWLB) or a fan-out wafer-level packaging (FoWLP), radio dies are embedded in a mold structure with same conductor layers for antenna and connections to a system PCB. The biggest challenges are thermal management of the RFIC die, as well as the limited flexibility in antenna design. However, materials and configurations to improve antenna performances are mandatory for efficient AoB solutions, as well as the flexibility of integrating additional functionalities.

Thus, a solution allowing an easy AoB size scalability and a flexible system integration with high performance electrical and thermal connections between the radio dies, the system board and the antenna board is desired.

SUMMARY

In view of the above-mentioned disadvantages, embodiments of the present invention aim to provide an improved RFIC sub-module and antenna device. In particular, an objective is to provide a flexible integration of the RFIC sub-module with high performance electrical and thermal connections. Further, an antenna device integrated with the RFIC sub-module is proposed. The RFIC sub-module and antenna device should allow better material and PCB layer thickness selections, scalability, thermal and electrical performance.

The objective is achieved by the embodiments of the invention as described in the enclosed independent claims. Advantageous implementations of the present invention are further defined in the dependent claims.

A first aspect of the invention provides a RFIC sub-module, comprising: a RFIC die, a first PCB comprising one or more connection elements provided on each of a top side and a bottom side of the first PCB, and one or more connection paths through the first PCB connecting the bottom side and the top side, wherein the RFIC die is attached to and electrically connected to one or more bottom side connection elements of the first PCB.

The RFIC sub-module with RFIC die allows vertical partitioning in z-direction in an antenna device, e.g. AoB device. The RFIC sub-module has high-frequency interconnects and thermal connections, which can route signals to a system PCB. Therefore, the RFIC submodule achieves flexible integration of the RFIC sub-module with high performance electrical and thermal connections in the antenna device. In an implementation form of the first aspect, one or more top side connection elements of the first PCB are attachable and electrically connectable to an antenna layer of the antenna device.

In order to allow signals to be routed from a system PCB to the antenna/radiating elements of an antenna device, the top side connection elements of the first PCB are physically attached to, and electrically connected to the antenna layer. The first PCB is particularly an antenna layer PCB.

In an implementation form of the first aspect, one or more bottom side connection elements of the first PCB are attachable and electrically connectable to a second PCB, particularly with high frequency interconnects and thermal heat dissipation paths.

Particularly, the second PCB may be a system PCB. Possibly, the bottom side connection elements are soldered, or in some other way attached, to the system PCB. These connections allow high frequency interconnects, as well as a good heat dissipation performance of the RFIC sub-module.

In an implementation form of the first aspect, the RFIC die is connectable to the antenna layer of the antenna device through one or more connection paths of the first PCB.

In order to route signals from a system PCB to an antenna element, the RFIC die can be connected to the antenna layer of the antenna device, particularly, through the connection path of the first PCB.

A second aspect of the invention provides an antenna device, comprising: an antenna layer comprising at least one antenna module, and a RFIC layer arranged below the antenna layer and comprising at least one RFIC sub-module according to the first aspect or any implementation form of the first aspect, wherein the RFIC sub-module layer is attached to and electrically connected to the antenna layer.

The antenna device is accordingly proposed with partitioning into different functionalities. In particular, a vertical partitioning in the z-direction allows a separation of the antenna device into an antenna layer and a layer of RFIC sub-modules. At the same time, a horizontal partitioning in x/y direction allows a separation of a lower part of the antenna device into individual RFIC sub-modules, thus providing easy scalability for different sizes of antenna devices. In an implementation form of the second aspect, the antenna layer is partially or fully partitioned into a plurality of antenna modules.

The antenna layer can be partially or fully partitioned into smaller antenna modules, even down to 1 antenna module per 1 RFIC sub-module. Any configuration in-between is also possible, e.g. 1x2, 2x1, 2x2, 1x3, 3x1, 2x3, 3x2, 3x3, n x n, n x m, m x n, m x m antenna modules per RFIC sub-module, wherein n, m are integers equal or larger 1.

In an implementation form of the second aspect, one antenna module from the plurality of antenna modules is electrically connected to one RFIC sub-module.

In order to allow signals to be routed from a system PCB to an antenna element, the antenna module should be electrically connected to one RFIC sub-module accordingly.

In an implementation form of the second aspect, an array of antenna modules from the plurality of antenna modules is electrically connected to one RFIC sub-module.

The antenna layer may comprise an antenna array. Possibly, the array of antenna modules may be electrically connected to one RFIC sub-module, based on a specific configuration of the antenna device.

In an implementation form of the second aspect, the RFIC sub-module is configured to route signals from a second PCB to the antenna module connected with the RFIC sub-module.

In an implementation form of the second aspect, the first PCB is made from glass, ceramic, low temperature co-fired ceramics, LTCC, or metal structures.

The first PCB, which may also be referred as the“antenna layer PCB”, does not have to be a PCB. It may be made from glass, ceramic, low temperature co-fired ceramics, LTCC, or metal structures.

In an implementation form of the second aspect, the RFIC sub-module layer is electrically connected to the antenna layer through soldering, conductive glue or a special spacer glue.

There are thus different kinds of suitable electrical interconnects between the RFIC sub-module layer and the antenna layer. In an implementation form of the second aspect, the RFIC die is a bare-die with bonding wires, solder bumps or flip-chip interconnections connected to the first PCB, and with through vias or hot vias connected to the second PCB.

The RFIC die can be mounted to the first PCB in different ways. The RFIC die can also be connected to the second PCB in different ways. The hot vias allow wave propagation from the system PCB to the RFIC die, and vice versa. The through vias allow a better thermal performance.

In an implementation form of the second aspect, the RFIC die is a lead frame or a laminate PCB based land grid array (LGA) package.

That means that the RFIC die itself is a molded plastic package with though mold vias for the vertical connections.

In an implementation form of the second aspect, the RFIC die is assembled onto the RFIC sub- module, or embedded into the RFIC sub-module.

The RFIC die can be embedded into the RFIC sub-module by an embedding technology.

In an implementation form of the second aspect, the RFIC die is arranged in a sealed cavity of the RFIC sub-module.

The RFIC sub-module may comprise at least one molded cavity, and the RFIC die is arranged inside of the cavity.

In an implementation form of the second aspect, the cavity is filled by a molding process, particularly using a laser activatable material.

The mold cavity itself can be made from a laser activatable material, for example a commercial laser activatable material.

In an implementation form of the second aspect, the cavity is metallized to form a laser direct structuring (LDS) heat spreader.

In particular, the LDS heat spreader may be arranged beneath the RFIC die.

In an implementation form of the second aspect, the RFIC sub-module is connected to a heat sink, particularly by means of holes or through vias in the second PCB according to an implementation form of the first aspect, wherein the holes or vias are plated and filled with a thermal interface material.

The second PCB, namely, the system PCB, can be with holes to connect the RFIC die to the heat sink. Alternatively, the second PCB can be without holes, then the thermal path is realized with vias through the second PCB.

In an implementation form of the second aspect, the RFIC sub-module layer comprises a plurality of RFIC sub-modules.

The RFIC sub-module layer may include more than one RFIC sub-module. The number of the RFIC sub-module that may be included in the RFIC sub-module layer may be up to 1024 or even 2048, depending on a design of the antenna device.

It has to be noted that all devices, elements, units and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof.

BRIEF DESCRIPTION OF DRAWINGS

The above described aspects and implementation forms of the present invention will be explained in the following description of specific embodiments in relation to the enclosed drawings, in which

FIG. 1 shows a RFIC sub-module according to an embodiment of the invention.

FIG. 2 shows an antenna device according to an embodiment of the invention.

FIG. 3 shows an antenna device according to an embodiment of the invention. FIG. 4 shows an antenna device according to an embodiment of the invention.

FIG. 5 shows an antenna device according to an embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a RFIC sub-module 100 according to an embodiment of the invention. The RFIC sub-module 100 comprises a RFIC die 101, e.g. a transceiver/receiver chip. Further, the RFIC sub-module 100 comprises a first PCB 102 comprising one or more connection elements 1021 provided on each of a top side and a bottom side of the first PCB 102. In addition, the RFIC die 101 is attached to and electrically connected to one or more bottom side connection elements 1021 of the first PCB 102.

To overcome the limitations of PCB and wafer level process based AoB technologies, vertical and horizontal partitioning in z and x/y directions of an antenna device (see e.g. FIG. 2) is proposed in combination with vertical RFID sub-modules 100.

Optionally, the RFIC sub-module 100 may be connected to an antenna element, e.g. an antenna layer 201 of an antenna device 200 according to an embodiment of the invention, as shown in FIG. 2. In particular, one or more top side connection elements 1021 of the first PCB 102 are attachable and electrically connectable to the antenna layer 201 of the antenna device 200.

Optionally, the RFIC sub-module 100 may also be connected to a system board, e.g. a second PCB 202 of the antenna device 200, as shown in FIG. 3. For instance, one or more bottom side connection elements 1021 of the first PCB 102 are attachable and electrically connectable to the second PCB 202 of the antenna device 200, particularly with high frequency interconnects and thermal heat dissipation paths 2021.

The RFIC die 101 may be connectable to the antenna layer 201 of the antenna device 200 through one or more connection paths 1022 of the first PCB 102.

FIG. 2 - FIG. 5 show antenna devices 200 according to embodiments of the invention. Each of these antenna devices 200 includes a RFIC sub-module 100 according to an embodiment of the invention, as shown in FIG. 1. Same elements in the figures are labelled with the same reference signs and function likewise. FIG. 2 shows an antenna device 200 comprising an antenna layer 201 comprising at least one antenna module 2011. The antenna device 200 further comprises a RFIC sub-module layer 203 arranged below the antenna layer 201 and comprising at least one RFIC sub-module 100. Particularly, the at least one RFIC sub-module 100 is the RFIC sub-module shown in FIG. 1. Further, the RFIC sub-module layer 203 is attached to and electrically connected to the antenna layer 201.

FIG. 3 shows an antenna device 200 based on FIG. 2, further comprising one or more second PCB 202 arranged below the first PCB 102. Optionally, the one or more bottom side connection elements 1021 of the first PCB 102 are attachable and electrically connectable to the second PCB 202, particularly with high frequency interconnects and thermal heat dissipation paths 2021, as shown in FIG. 3.

FIG. 4 shows an antenna device 200 according to an embodiment of the invention. Particularly, the antenna device 200 may comprise an antenna layer 201 including at least one antenna module 2011. Further, the antenna device 200 may comprise a RFIC sub-module layer 203 including more than one RFIC sub-module 100, e.g. 4 RFIC sub-modules 100. Each RFIC sub- module 100 may be the RFIC sub-module shown in FIG. 1. Possibly, at least one of the more than one RFIC sub-module 100 may, however, not be the exact the same RFIC sub-module 100. The RFIC sub-module 100 in the RFIC layer 203 may have different designs to fulfill the different functionality requirements. Accordingly, the antenna layer 201 of the antenna device 200 may also comprise a plurality of antenna modules 2011.

Optionally, one antenna module 2011 from a plurality of antenna modules is electrically connected to one RFIC sub-module 100, particularly through one or more top side connection elements 1021 of the first PCB 102. Possibly, an array of antenna modules 2011 from the plurality of antenna modules is electrically connected to one RFIC sub-module 100.

The RFIC die 101 in each RFIC sub-module 100 may be connectable to the antenna layer 201 of the antenna device 200 through one or more connection paths 1022 of the first PCB 102. In addition, one or more bottom side connection elements 1021 of the first PCB 102 are attachable and electrically connectable to the second PCB 202 of the antenna device 200, particularly with high frequency interconnects and thermal heat dissipation paths 2021. In this way, the RFIC sub-module 100 is able to route signals from the second PCB 202 to the antenna module 2011, or the array of antenna module 2011, which is connected with the RFIC sub-module 100. FIG. 5 shows an antenna device 200 according to an embodiment of the invention. Particularly, the antenna device 200, as shown in FIG. 5, is similar to the antenna device 200, as shown in FIG. 4, with separated antenna modules 2011. The RFIC sub-module 100 is arranged below each separated antenna module 2011 of the antenna layer 201, and above one or more second PCB 202.

The antenna layer 201 of the antenna device 200 may be partially or fully partitioned into a plurality of antenna modules 2011. For instance, one antenna module 2011 per each RFIC sub- module 100 can be implemented, as shown in FIG. 5. Alternatively, any other configuration is also possible, e.g. a 2 x 2 array of antenna modules 2011 per RFIC sub-module 100. Therefore, one antenna module 2011 from the plurality of antenna modules may be electrically connected to one RFIC sub-module 100, or an array of antenna modules 2011 from the plurality of antenna modules may be electrically connected to one RFIC sub-module 100. It should be noted that, the RFIC sub-module 100 can provide signals to more antenna elements, i.e. antenna modules 2011.

A size of a single antenna module 2011 may depend on an applied frequency and a chosen antenna configuration. Consequently, a dimension of the antenna device 200 according to embodiments of this invention, can vary significantly, depending on amounts of antenna modules and a number of RFIC sub-module 100. Therefore, a size of an overall antenna device

200 is scalable very well.

In addition, in order to overcome the limitations of PCB and wafer level process-based AoB technologies, namely, a high cost due to the expensive PCB materials, materials used in the antenna device 200 according to embodiments of the invention can be optimized for different functionalities. In addition, layer thickness of the antenna device 200 is also optimized. Particularly, the first PCB 102 of the RFIC sub-module 100 may be made from glass, ceramic, LTCC, or metal structures.

Optionally, the RFIC sub-module layer 203 may be electrically connected to the antenna layer

201 through different kind of electrical interconnects. For instance, soldering, conductive glue or a special spacer glue to reduce the tolerances in z-direction to a minimum value may be used.

Optionally, the RFIC die 101 in all embodiments can be a so-called bare-die with bonding wires, solder bumps or flip-chip interconnections (e.g. Cu Pillar flip-chip interconnections) connected to the first PCB 102. That means, the RFIC die 101 can be mount to the first PCB 102 in many different ways. Though vias or hot vias may be used for the connections from the RFIC die 101 to the second PCB 202. The hot vias allow wave propagation from the second PCB 202 to the RFIC die 101 and vice versa. The through via allows a better thermal performance.

The RFIC die 101 in all embodiments can also be a lead frame or laminate PCB based LGA package, which means that the RFIC die 101 itself is a molded plastic package with though mold vias for the vertical connections.

Optionally, the RFIC die 101 can be assembled onto the RFIC sub-module, or embedded into the RFIC sub-module 100, e.g. by an embedding technology.

Optionally, The RFIC sub-module 100 may comprise at least one sealed cavity. The cavity may be overmolded or filled with a suitable material, e.g. a resin material. The RFIC die 101 may be arranged inside of the cavity. Optionally, the RFIC die 101 is connected to the first PCB 102 with solder bumps or flip-chip interconnections. For instance, there may be only one RFIC sub- module 100 is arranged in each cavity. Alternatively, multiple RFIC sub-module 100 may also be arranged in same cavity.

Optionally, the cavity may be filled or sealed by a molding process, particularly using a laser activatable material. Further, the cavity may be metallized to form a LDS heat spreader. It should be noted that a surface-mount technology (SMT) process may be used to connect the RFIC sub-module layer 203 to the second PCB 202. The LDS heat spreader can be soldered to the second PCB 202 in the same SMT process which is used to connect the RFIC sub-module layer 203 to the second PCB 202. This efficiently simplifies a manufacturing process of the antenna device 200.

Further, the RFIC sub-module 100 may be connected to a heat sink 204, particularly by means of holes or through vias in the second PCB 202, wherein the holes or vias are plated and filled with a thermal interface material. Particularly, the second PCB 202, namely, the system PCB, can be with holes to connect the RFIC die 101 to the heat sink 204. Or the second PCB 202 can be without holes, then the thermal path is realized with vias through the second PCB 202.

Optionally, the RFIC sub-module layer 203 may comprise a plurality of RFIC sub-modules 100. For instance, a number of the RFIC sub-module 100 that may be included in the RFIC sub- module layer 203 may be up to 1024 or even 2048, depending on a design of the antenna device

200.

In summary, the embodiments of the present invention provide a simple integration solution of RFIC dies. Especially, a solution of vertical and horizontal partitioning in z and x/y directions in combination with vertical RFIC dies is proposed. The antenna device includes: a RFIC sub- module layer with high-frequency interconnects and thermal connections to a system PCB, and an antenna layer or antenna modules with radiating patch antenna elements stacked onto the RFIC sub-module layer. Vertically (in z-direction), the antenna device can be separated into an antenna layer and a layer of RFIC sub-modules. Therein the RFIC sub-modules contain the RFIC dies and are connected at their bottom side to the system PCB for the high frequency interconnects as well as for the thermal heat dissipation path. On the top side, the RFIC sub- modules have electrical connections to the antenna layer. The antenna layer is with its materials and PCB layer thicknesses optimized for the antenna function. Horizontally (in x/y direction), a lower part of the antenna device can be separated into individual RFIC sub-modules to allow an easy scalability for different antenna sizes. Therefore, a scalable antenna device with high performance electrical and thermal connections is implemented according to embodiments of the invention. Meanwhile, the materials and layer thicknesses are also optimized for the different functionalities.

The present invention has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed invention, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word “comprising” does not exclude other elements or steps and the indefinite article“a” or“an” does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.

Claims

1. A radio frequency integrated circuit, RFIC, sub-module (100) for an antenna device (200), the RFIC sub-module (100) comprising:

a RFIC die (101), and

a first printed circuit board, PCB (102), comprising one or more connection elements (1021) provided on each of a top side and a bottom side of the first PCB, and one or more connection paths (1022) through the first PCB (102) connecting the bottom side and the top side,

wherein the RFIC die (101) is attached to and electrically connected to one or more bottom side connection elements (1021) of the first PCB (102).

2. RFIC sub-module (100) according to claim 1, wherein

one or more top side connection elements (1021) of the first PCB (102) are attachable and electrically connectable to an antenna layer (201) of the antenna device (200).

3. RFIC sub-module (100) according to claim 1 or 2, wherein

one or more bottom side connection elements (1021) of the first PCB (102) are attachable and electrically connectable to a second PCB (202), particularly with high frequency interconnects and thermal heat dissipation paths (2021).

4. RFIC sub-module (100) according to claim 2 or 3, wherein

the RFIC die (101) is connectable to the antenna layer (201) of the antenna device (200) through one or more connection paths (1022) of the first PCB (102).

5. Antenna device (200), comprising:

an antenna layer (201) comprising at least one antenna module (2011), and

a radio frequency integrated circuit, RFIC, sub-module layer (203), arranged below the antenna layer (201) and comprising at least one RFIC sub-module (100) according to one of the claims 1 to 4,

wherein the RFIC sub-module layer (203) is attached to and electrically connected to the antenna layer (201).

6. Antenna device (200) according to claim 5, wherein

the antenna layer (201) is partially or fully partitioned into a plurality of antenna modules (2011).

7. Antenna device (200) according to claim 6, wherein

one antenna module (2011) from the plurality of antenna modules (2011) is electrically connected to one RFIC sub-module (100).

8. Antenna device (200) according to claim 6, wherein

an array of antenna modules (2011) from the plurality of antenna modules (2011) is electrically connected to one RFIC sub-module (100).

9. Antenna device (200) according to one of the claims 5 to 8, wherein

the RFIC sub-module (100) is configured to route signals from a second PCB (202) to the antenna module (2011) connected with the RFIC sub-module (100).

10. Antenna device (200) according to one of the claims 5 to 9, wherein

the first PCB (102) is made from glass, ceramic, low temperature co-fired ceramics, LTCC, or metal structures.

11. Antenna device (200) according to one of the claims 5 to 10, wherein

the RFIC sub-module layer (203) is electrically connected to the antenna layer (201) through soldering, conductive glue or a special spacer glue.

12. Antenna device (200) according to one of the claims 5 to 11 and according to claim 9, wherein

the RFIC die (101) is a bare-die with bonding wires, solder bumps or flip-chip interconnections connected to the first PCB (102), and with through vias or hot vias connected to the second PCB (202).

13. Antenna device (200) according to one of the claims 5 to 12, wherein

the RFIC die (101) is a lead frame or a laminate PCB based land grid array, LGA, package.

14. Antenna device (200) according to one of the claims 5 to 13, wherein

the RFIC die (101) is assembled onto the RFIC sub-module (100), or embedded into the RFIC sub-module (100).

15. Antenna device (200) according to one of the claims 5 to 14, wherein

the RFIC die (101) is arranged in a sealed cavity of the RFIC sub-module (100).

16. Antenna device (200) according to claim 15, wherein

the cavity is filled by a molding process, particularly using a laser activatable material.

17. Antenna device (200) according to claim 16, wherein

the cavity is metallized to form a laser direct structuring, LDS, heat spreader.

18. Antenna device (200) according to one of the claims 5 to 17, wherein

the RFIC sub-module (100) is connected to a heat sink (204), particularly by means of holes or through vias in the second PCB (202) according to claim 9, wherein the holes or vias are plated and filled with a thermal interface material.

19. Antenna device (200) according to one of the claims 5 to 18, wherein

the RFIC sub-module layer (203) comprises a plurality of RFIC sub-modules (200).