An antenna array having an independent RFIC chip and a lattice arrangement of antenna elements

Abstract

The antenna apparatus includes a first component layer having a plurality of RFICs arranged in a first grid configuration (e.g., rectangular), each RFIC including a beamforming circuit. A second, parallel component layer overlies the first component layer and includes a plurality of antenna elements arranged in a second, different grid configuration (e.g., triangular). The antenna elements each have a respective feed point connected to an input / output (I / O) pad of the RFIC. Each I / O pad is aligned with the feed point connected to the I / O pad along an axis orthogonal to the first and second layers.

Description

Technical Field

[0001] (Related Applications) This patent application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 011,056, filed Apr. 16, 2020, entitled “Antenna Array with Independent RFIC Chip and Antenna Element Lattice Geometries,” the entire disclosure of which is incorporated herein by reference.

[0002] (Field of the Invention) The present disclosure generally relates to antenna arrays having distributed RFIC chips.

Background Art

[0003] Consideration of Related Art Antenna arrays are currently used in various applications at microwave and millimeter-wave frequencies, such as in aircraft, satellites, vehicles, and base stations for general terrestrial communication. Such antenna arrays typically include microstrip radiating elements driven using a phase shift beamforming circuit to form a phased array for directing a beam. In many cases, it is desirable for the entire antenna system, including the antenna array and the beamforming circuit, to meet the required performance metrics while occupying minimal space with a low profile.

[0004] A "buried" antenna array may be defined as an antenna array composed of antenna elements integrated with a radio frequency integrated circuit chip (RFIC) in a compact structure. The buried array can have a sandwich configuration in which the antenna elements are disposed within an external component layer and the RFIC (radio frequency integrated circuit chip) is distributed across the effective antenna apertures in an adjacent parallel component layer behind the antenna element layer. The RFIC can include a power amplifier (PA) for transmission, a low noise amplifier (LNA) for reception, and / or a phase shifter for beam steering. By thus distributing the PA (power amplifier) and LNA (low noise amplifier), higher efficiency during transmission and improved noise performance during reception can be achieved. The reliability of the antenna array can also be improved, because even if a small number of the amplifiers malfunction, the overall antenna performance remains acceptable. The RFIC typically includes other beamforming circuits such as filters, impedance matching elements, RF couplers, transmit / receive (T / R) switches, and control lines. SUMMARY OF THE INVENTION

[0005] In one aspect of the present disclosure, an antenna device includes a first component layer including a plurality of RFICs disposed in a first plane having a first grid arrangement, each RFIC including a beamforming circuit. A second component layer is overlaid on the first component layer and includes a plurality of antenna elements disposed in a second different grid arrangement in a second plane parallel to the first plane. Each antenna element has a respective feeding point connected to an input / output (I / O) pad of the RFIC. The I / O pads are aligned with the feeding points connected to the I / O pads along an axis orthogonal to the first and second planes.

[0006] The first grid arrangement may be rectangular, and the second grid arrangement may be triangular.

[0007] Since the I / O pads of the RFIC are aligned with the power feeding points of the antenna elements, it is possible to avoid an additional rewiring layer between the transmission line and / or the first layer and the second layer, enabling a compact and low-loss design.

Brief Description of the Drawings

[0008] The above and other aspects and features of the disclosed technology will become more apparent from the following detailed description in conjunction with the accompanying drawings, in which like reference numerals indicate like elements or features. Various elements of the same or similar type may be distinguished by adding a dash and a second label that differentiates between the same / similar elements to the reference label (e.g., -1, -2), or by directly adding a second label to the reference label. However, if a given description uses only the first reference label, it is applicable to any one of the same / similar elements having the same first reference label regardless of the second label. Elements and features may not be drawn to scale in the drawings.

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[0009] The following description is provided to assist in a comprehensive understanding of specific exemplary embodiments of the technology disclosed herein for illustrative purposes with reference to the accompanying drawings. This specification includes various specific details to assist those skilled in the art in understanding the technology, but these details should be regarded as merely illustrative. For the sake of brevity and clarity, descriptions of well-known functions and structures may be omitted if they may obscure the understanding of the technology by those skilled in the art.

[0010] FIG. 1 is a top view of an exemplary antenna device 100 according to one embodiment. The antenna device 100 may be configured with a thin laminated structure having an upper component layer including a plurality of antenna elements 120 forming an antenna array in a first plane, and a lower component layer disposed in a second plane parallel to the first plane and including a plurality of radio frequency integrated circuit chips (RFICs) 110 connected to the antenna elements 120. A substrate 150 may be disposed between the upper component layer and the lower component layer. A ground plane (not shown) for reflecting signal energy with the antenna elements 120 may be printed on the lower surface of the substrate 150. With such a multilayer structure having integrated antenna elements 120 and RFICs 110, the antenna device 100 may be referred to as an embedded antenna array. In the following description, for convenience of explanation, the horizontal plane / direction generally refers to a plane / direction parallel to the main surface of the antenna device 100, and the vertical direction refers to the orthogonal direction, i.e., the thickness direction of the antenna device 100.

[0011] Each of the antenna elements 120 may be a microstrip patch antenna element printed on the substrate 150 and electrically or electromagnetically coupled (``fed'') to the RFIC 110 at respective feeding points 122. The RFIC 110 can be mechanically connected to the substrate 150, such as by solder bump connections to a ground plane and other connection pads disposed on the substrate 150. Each RFIC 110 can include a transmit and / or receive RF front-end circuit including an amplifier, a phase shifter, and a filter. (In this specification, the RF front-end circuit may be interchangeably referred to as a ``beamforming'' circuit.) With RF front-end amplifiers thus distributed across the antenna array, the antenna device 100 may be referred to as an active antenna array. In some embodiments, each RFIC 110 includes a receive circuit including at least one low noise amplifier (LNA) for amplifying received signals and at least one power amplifier (PA) for amplifying transmit signals. When the antenna device 100 is designed as a phased array, each RFIC 110 can include at least one dynamically controllable phase shifter for steering receive and / or transmit beams.

[0012] In one embodiment, the antenna device 100 is configured for operation over a millimeter (mm) wave frequency band, which is generally defined as a band in the range of 30 GHz to 300 GHz. In other examples, the antenna device 100 operates in the microwave range of about 1 GHz to 30 GHz or in the sub-microwave range below 1 GHz. In this specification, a radio frequency (RF) signal means a signal having a frequency below 1 GHz to 300 GHz. Note that an RFIC configured to operate at microwave or millimeter wave frequencies is often referred to as a monolithic microwave integrated circuit (MMIC) and is typically made from III-V semiconductor materials.

[0013] When the antenna element 120 is realized as a microstrip patch, it can have any suitable shape such as square, rectangular, circular, elliptical, or a deformation thereof, and can be provided and configured in a manner sufficient to achieve a desired polarization, such as circular, linear, or elliptical. The number, types, sizes, shapes, element-to-element spacing, and the manner in which they are provided of the antenna elements 120 may be changed by design to achieve the targeted performance metrics. FIG. 1 shows an example having 64 antenna elements 120, but in a typical embodiment, the antenna device 100 includes hundreds or thousands of antenna elements 120. In the embodiments described below, each antenna element 120 is a microstrip patch provided with probe feeding. The probe feeding may be implemented as a through-substrate via (TSV) (a "via") that is electrically connected to the input / output (I / O) pads of the RFIC 110. The I / O pads are interfaces that enable signals to be input to and output from the RFIC 110. In other examples, an electromagnetic feeding mechanism is used instead of the via, and each antenna element 120 is excited by near-field energy from its respective feeding point.

[0014] In the antenna device 100, the RFIC 110 is arranged in a first grid arrangement, and the antenna element 120 is arranged in a second (different) grid arrangement. In FIG. 1 and other examples in this specification, the first grid arrangement is rectangular (in this specification, "square" is a subset of "rectangular"), and the second grid arrangement is non-rectangular, such as triangular, but other combinations are also possible in other embodiments. The non-rectangular antenna array grid arrangement (e.g., triangular) can provide desirable performance advantages, such as allowing a wider spacing of the antenna elements 120 with grating lobe-free performance compared to a rectangular grid. The mutual coupling between the antenna elements 120 can also be beneficially reduced in a triangular grid compared to a rectangular grid configuration.

[0015] In either case, the RFIC 110 and the antenna element 120 are arranged in different respective grid arrangements, but each feeding point 122 is vertically aligned with the corresponding I / O pad of the RFIC 110 connected to that feeding point. For example, the area of each feeding point 122 in FIG. 1 is represented as "○", and the "×" within each "○" represents the connected RFIC 110 I / O pad. Thus, in the vertical direction, the feeding point 122 overlaps the I / O pad. In other words, the I / O pads of the various RFIC 110s arranged in the horizontal plane define a pattern that coincides with the pattern of the feeding points 122. This alignment configuration shortens the distance between each feeding point 122 and the corresponding I / O pad and eliminates the need for lossy transmission lines that traverse horizontally between them. Conventionally, these transmission lines have been formed within the multilayer connection between the RFIC 110 and the antenna substrate 150. This is partly because the I / O pads on a standard RFIC are arranged symmetrically adjacent to the opposing edges of their rectangular footprints. This embodiment enables the elimination of such multilayer connections and the reduction / elimination of the losses caused by such transmission lines otherwise.

[0016] In FIG. 1, the power supply point 122 of the RFIC 110 and the positions of the I / O pads are shown vertically aligned. As used herein, "alignment" of the power supply point with the I / O pads connected thereto can be either exact alignment (within manufacturing tolerances) or "substantially aligned" (described below) with a slight offset incorporated for manufacturing purposes. FIG. 1 also shows a case where each RFIC 110 is connected to four antenna elements 120. In other embodiments, each RFIC 110 is connected to more or fewer antenna elements 120. Also, in some embodiments, each of the antenna elements 120 is shared for transmission and reception operations, and it should also be noted that each RFIC 110 includes appropriate transmit / receive (T / R) circuitry internally for separating signals in the transmit and receive paths. However, in other antenna systems, two separate antenna arrays 100 are used, one for transmission and the other for reception. In this case, all of the antenna elements 120 of a given antenna array 100 are either "receive antenna elements" dedicated to reception operations or "transmit antenna elements" dedicated to transmission operations.

[0017] Each grid arrangement can be defined by the center point 123 of the antenna element 120 and the center point 113 of the RFIC 110. (Note that the feeding point 122 may be offset from the center point 123 of the antenna element 120.) Referring to FIG. 2, the virtual line connecting the center points 123 forms a triangular grid 202 of the antenna element 120. The virtual line connecting the center points 113 of the RFIC 110 forms a rectangular or square grid 204 of the RFIC 110. As seen in FIG. 1, in the case of four antenna elements 120 connected to each respective RFIC 110 in such a grid arrangement, in any given RFIC 110, two I / O pads (x within the feeding point 122) are located at the opposing edges of the RFIC, and the other two I / O pads are located inward from the opposing edges. Generally, when each RFIC 110 within a rectangular grid is connected to at least two antenna elements 120 within a non-rectangular grid, some of the RFIC I / O pads may be arranged at the opposing edges of the RFIC 110, and the remaining I / O pads are arranged inward from these opposing edges. This I / O pad arrangement is different from a standard RFIC (having a rectangular footprint) in which all of its I / O pads are typically arranged in proximity to the opposing edges (including the "G" ports of a ground-signal-ground ("GSG") or ground-signal ("GS") connection set, described later). As a result, when a standard RFIC is arranged in a rectangular grid and connected to antenna elements of a non-rectangular grid, some or all of the feeding point positions will not be aligned with the I / O pad positions. This complicates the design as horizontal transmission lines are required and makes the interconnection between the RFIC and the antenna element difficult and lossy. The present embodiment using aligned feeding points and I / O pads avoids such complexity and transmission line losses.

[0018] FIG. 3 is a simplified cross-sectional view of a portion of the antenna device 100 showing an exemplary structure along two adjacent RFICs 110 of FIG. 1. A plurality of vias 302 are formed in the substrate 150, each connecting a feeding point 122 of the antenna element 120 to an RFIC 110 I / O pad (not shown in FIG. 3) at the I / O pad location 315. Hereinafter, it is assumed that the I / O pad location 315 is the center position of the I / O pad. Details of the I / O pad will be described later.

[0019] The ground plane 340 may be printed on the lower surface of the substrate 150. Since the positions of the feeding points 122 and the corresponding I / O pad positions 315 are vertically aligned, one or more rewiring layers having transmission lines horizontally oriented between the RFIC 110 and the substrate 150 can be avoided. Thus, it may be directly attached to the connection points in the RFIC 110wo, the substrate 150, and the ground plane 340. Further, the alignment between the I / O pad position 315 and the corresponding feeding point position 122 reduces the complexity of the antenna substrate 150 (including the number of required substrate layers). Note that the number of dielectric layers and conductive layers in the antenna substrate 150 may vary depending on the embodiment. It should be further noted that in some embodiments, each antenna element 120 can have two feeding points connected to two respective I / O pads of the RFIC 110 via two vias 302 in order to form circularly polarized waves in some designs. However, in the design of the antenna element 120 described below, circularly polarized waves are realized using single feeding. Further, when GSG connection is performed, the ground pad of the RFIC 110 may be connected to the ground plane 340 at positions 317 on both sides of the via 302. Alternatively, a GS connection in which the connection between a single ground pad and the ground plane 340 is made only on one side of the via 302 is used.

[0020] FIG. 4A is a cross-sectional view of an exemplary connection structure 400 between one antenna element 120 and the RFIC 110 in the antenna device 100. In this embodiment, an “exact” vertical alignment between the feeding point 122 and the touch pad position 315 is targeted by a design via the connection via 302. (Due to manufacturing tolerances described below, a predetermined range of horizontal offsets can be assigned even in the case of this “exact alignment.”) The via 302 makes electrical contact with the antenna element 120 at the position of the feeding point 122, penetrates the antenna substrate 150, and connects the antenna element 120 to a catch pad 406 on the bottom surface 453 of the substrate 150. The position of the feeding point 122 is the center of the electromagnetic interface with the antenna element 120. In the illustrated example, the via 302 makes direct contact with the antenna element 120, and thus the feeding point 122 is at the center of the upper surface of the via 302. In other embodiments where the antenna element 120 does not physically contact the via and is capacitively coupled to the slot, the position of the feeding point may be at the optimal coupling position of the slot.

[0021] For example, via 302 can be cylindrical and have a diameter D passing through the central axis 425, and the intersection of axis 425 and antenna element 120 defines the position of feeding point 122. (When via 302 has an elliptical cross-section, D can represent the distance across any cross-section of the ellipse) Catch pad 406 can have a footprint with a diameter or width that is approximately the same as diameter D or slightly larger than diameter D for manufacturing tolerance purposes, and can be welded and patterned with a conductive material. RFIC 110 has I / O pad 412 connected to catch pad 406 via electrical connection joint 420s (where "s" indicates a "signal" line connection). This connection enables signal communication between antenna element 120 and a beamforming circuit (not shown) within RFIC 110. I / O pad 412 can be cylindrical, elliptical, or rectangular centered around central axis 435. I / O pad position 315 can be defined as a position along central axis 435. In an example of exact alignment in FIG. 4A, the desired alignment tolerance (i.e., the allowable level offset due to manufacturing variation) between axis 435 and axis 425 can be about 1 / 4 D. Such a minimum or zero offset minimizes the length of the signal path between the position of feeding point 122 and I / O pad position 315 for a given thickness of antenna substrate 150 and conductive bonding material (the thickness of connection joint 420s). Thereby, antenna element 120 can be directly connected to RFIC 110 via via 302 and the conductive bonding material (e.g., solder) of connection joint 420s without the need for additional transmission lines or multi-layer connections. An example of the diameter D of via 302 for millimeter-wave design is in the range of 50 - 100 μm. The typical alignment accuracy of RFIC 110 in the case of exact alignment can be about 5 μm. In millimeter-wave design, an example of the diameter or width of antenna element 120 is in the range of 1 - 2 mm, and the spacing between elements is in the range of about 2 - 4 mm in each of the X and Y directions. RFIC 110 can each have a length and width in the range of about 4 - 6 mm. The thickness (the height seen in FIG. 4A) of RFIC 110 and underfill layer 410 can be about 3 mm, and the thickness of antenna substrate 150 can be about 10 mm.All of the above dimensions are exemplary for understanding the small scale typical of millimeter-wave applications and can be changed by design and / or according to frequency and manufacturing accuracy.

[0022] Also, FIG. 4A shows a GSG connection example in which grounding connections are made at two locations 317 on the opposite side across the connection to the connection joint 420s of the signal line described above. Each grounding connection is made by connecting the ground pad 408 of the RFIC 110 to the ground plane 340 at the position 317 via the grounding connection joint 420g. The isolation layer 410 can be composed of an underfill material surrounding each of the connection joints 420s, 420g to provide mechanical support to the connection joints 420s, 420g and thereby improve reliability. A typical underfill material may be a mixed material mainly composed of amorphous fused silica. In other embodiments, the underfill material is omitted, and thereby the isolation layer 410 simply represents air. To insulate the via 302 from the ground plane 340, an area of the ground plane 340 surrounding the catch pad 406 is cut away to expose the lower surface 453 of the antenna substrate 150. This feature can be best seen in FIG. 4B, which is a cross-sectional view through the connection joints 420s, 420g looking towards the substrate 150 (with the isolation layer 410 removed for clarity). Some examples of the connection joints 420s and 420g are copper pillar connection joints, solder joints (e.g., formed from solder balls), and gold-gold bumping connections. As described above, alternative embodiments can use a GS connection having only a single grounding connection on one side of the signal connection. The GSG connection design provides more isolation and reduces crosstalk than the GS design, but is more complex. The GSG connection can have more than three grounding connection joints 420g in some designs, but the actual implementation form has two connection joints 420g.

[0023] In FIG. 4A and other figures of this specification, the antenna substrate 150 is shown as a single-layer substrate. In other embodiments, the antenna substrate 150 is a multi-layer substrate having a patterned metal layer for providing some inter-chip RF routing between the RFICs 110 and / or connections between DC lines on the RFICs 110. In this metal layer, metal is removed in the region of the vias 302 to enable a direct connection between the RFIC 110 and the antenna element 120. Here, a single I / O pad 412 is shown in FIG. 4A, but in other embodiments, it should be further noted that in an alternative manner to achieve circular polarization, two or more I / O pads 412 are connected to each antenna element 120.

[0024] FIG. 5 is a cross-sectional view of another exemplary connection structure 500 between the antenna element 120 and the RFIC 110. In this example, the feeding point 122 is “substantially aligned” but not exactly aligned with the I / O port position 315 of the RFIC 110. (In this case too, it can be considered as a subset of the “aligned” configuration as described above.) For this purpose, a wider catch pad 506 extends under the via 302, and the via 302 is connected only to the first portion of the catch pad 506. The signal connection joints 520s are under the second portion beyond the first portion of the catch pad 506. Thus, the connection joints 520s are not directly under the via 302. This technique is advantageous when the process for forming the connection via 302 results in a non-planar bottom surface of the via 302 that can be translated parallel to the bottom surface of the catch pad. For example, in the configuration of FIG. 4A, when the catch pad 406 has a non-planar bottom surface, the reliability of the connection joints 420s can be lower than desired. In FIG. 5, even if the right side portion under the via 302 has a non-planar bottom surface, the reliability is improved by replacing it with an extended catch pad 506 having a planar bottom surface on the left side. As a result, a more reliable connection with the connection joints 520s can be formed. The RFIC 110 in this case includes I / O pads 512 that are symmetric about the central axis 535. The central axis 425 of the via 302 is horizontally offset from the axis 535 by a distance d1, where a typical value of d1 can be about D (the diameter of the via 302). Although there is an offset between the position of the feeding point 122 and the I / O pad position 315, since the offset is small, the two positions are considered to be aligned. For example, with respect to the wavelength, the maximum value of the offset d1 may be 0.02 wavelengths at the operating frequency of the antenna device 100, which may have a negligible electrical impact on the antenna performance compared to the exact alignment embodiment of FIG. 4A.

[0025] FIG. 6 shows a cross-sectional view of an exemplary detailed connection structure 600 between the antenna element 120 and the RFIC 110 within the antenna device 100. The illustrated connection structure 600 is an example of the connection structure 500 of FIG. 5 and shows a closely aligned flip-chip type connection in which the via 302 is slightly horizontally offset from the center point 315 of the I / O pad 612 of the RFIC 110. Alternatively, the via 302 may be exactly aligned with the I / O pad 612, in which case the configuration would be a detailed example of the connection structure 400 of FIG. 4. The RFIC 110 may be a semiconductor die composed of III-V materials for microwave and millimeter-wave designs, or silicon for lower frequencies. Some examples of III-V materials include indium phosphide (InP), gallium arsenide (GaAs), silicon germanium (SiGe), and gallium nitride (GaN). The active die side region 637 of the RFIC 110, e.g., the upper region of the RFIC 110 above the virtual line 635, faces the antenna element 120. The active die side region 637 may include doping regions of transistors used in beamforming circuits, e.g., low noise amplifiers, power amplifiers, T / R switches, phase shifters, etc. The bottom surface 631 is plated with metal and may be used as a ground for the internal circuits of the RFIC 110.

[0026] Between the I / O pad 612 and the connection joint 520s, a surface finishing metal layer 624 such as electroless nickel electroless palladium immersion gold plating (ENEPIG) may be present to assist the liquefiable metal (e.g., solder) of the connection joint 520s to adhere to the I / O pad 612. The layer 624 may be formed in a general shape of a frustum of a cone with a central cavity on its upper surface to provide a more reliable connection interface. In the flip-chip connection formation process, when solder balls or other metal structures are placed and then the upper part of the layer 624 is liquefied, a part of the liquid metal fills the upper cavity. This helps to form the connection joint 520s as a robust connection between the catch pad 506 and the I / O pad 612. In the example of FIG. 6, the metal routing layer 616 functions as a redistribution layer for connecting circuit points within the RFIC 110 and / or between different RFICs 110. For this purpose, a first polymer overcoat layer 622 such as benzocyclobutene (BCB) may be formed between the upper surface of the RFIC 110 and the metal routing layer 616, and a second polymer overcoat layer 614 may be formed between the metal routing layer 616 and the separation layer 410. The layers 622 and 614 provide separation and support for the metal routing layer 616. The material of the layer 622 may overlap the peripheral portion of the I / O pad 612 as shown. When the metal routing layer 616 is omitted, the first polymer overcoat layer 622 may still be present on the upper surface of the RFIC 110. The separation layer 410 surrounds the connection joint 520s and extends between the overcoat layer 614 and the lower surface of the antenna substrate 150. A similar connection structure can be provided to connect the ground pad 408 to a ground plane 440 (both not shown in FIG. 6). That is, the ground pads 408 may each be configured similarly to the I / O pad 612, and the surface finishing metal layer 624 may be present between each ground pad 408 and the corresponding connection joint 520s, similar to the connection joint 420g in FIG. 6.

[0027] The flip-chip connection configuration of FIG. 6 is sufficient to provide a short aligned connection between the power supply point 122 and the I / O pad 612, but may exhibit the side effect of signal loss caused by interfacing the polymer overcoat layer 622 with the active die side of the RFIC 110. Another possible side effect is due to the proximity between the active die side region 637 and the antenna ground plane 440 (seen in FIG. 4) located between the isolation layer 410 and the antenna substrate 150. This causes a risk of oscillation due to reflection between the ground plane 440 and the circuits within the active die side region 637.

[0028] FIG. 7A is a cross-sectional view of an exemplary dual-via type connection structure 700 between the antenna element 120 and the RFIC 110 in the antenna device 100. (The connection structure 700 is shown inverted 180° with respect to those in FIGS. 3 - 6.) The connection structure 700 is different from the structure 600 of FIG. 6 in that the active die side of the RFIC 110 does not interface with the polymer layer, thereby avoiding losses that would otherwise occur due to such an interface. Also, since the antenna ground plane and the region of the active die side of the RFIC 110 are not further separated and opposed to each other, oscillation due to reflection between these regions is less likely to occur.

[0029] The RFIC 110 of FIG. 7A has an active die side region 737 above the virtual line 735. A first via 732 formed through the die of the RFIC 110 is electrically connected to the conductive trace 724 in a local region of the active die side region 737. The local region may be a conductive I / O node of the beamforming circuit within the RFIC 110, and the conductive trace 724 may be connected to another circuit point of the beamforming circuit. Since the first via 732 is not electrically connected to the ground, it may be called a "hot via". The first via 732 is connected at the opposite end to an I / O pad 712 located on the lower surface of the RFIC 110 facing the active side region 737. The I / O pad 712 is connected to the antenna element 120 at the power feeding point 122 via a series of conductors. These may include copper pillars 752 or gold / solder bumps, solder caps 754 (or other liquefiable metal caps), a surface finishing metal layer 756 such as ENEPIG, a catch pad 706, and a second via 702 formed through the antenna substrate 150. The signal connection joints 720s include copper pillars 752 and solder caps 754. The copper pillars 752 may be formed by growing copper into pillars, and the solder caps 754 are applied to generate the signal connection joints 720s as solder connections. The catch pad 706 is formed on the rear surface 453 of the substrate 150 and may be similar to the catch pad 506 of FIG. 5. A passivation layer 760, such as a quartz polymer layer, can surround the surface finishing metal layer 756 and may be formed partially on the substrate surface 453 and partially on the exposed surface of the catch pad 706. As will be described below with the example of FIG. 7B, one or more passivation layers 760 can act as an insulator between the ground plane 440 and one or more redistribution metal layers between the substrate 150 and the RFIC 110.

[0030] For example, when via 702 is formed, a non-planar surface can occur near the surface 453 of substrate 150, which can be translated to an adjacent region of catch pad 706. Thus, catch pad 706 can be designed to extend horizontally as shown, so that the connection joint regions (layers 756, 754, and 752) to RFIC 110 can have higher strength and reliability. The same applies to via 732 and catch pad 712. Since the horizontal extensions of catch pads 706 and 712 can be similar, feed point 122 can be substantially or exactly aligned with the position 315 of I / O pad 712 (i.e., aligned as previously defined). Further, even if catch pads 706 and 712 are not designed to extend in the same direction, the offset between each via 702, 732 and the central axis of connection joint 720s is small (e.g., less than 0.02 wavelengths), so I / O pad position 315 and antenna feed point 122 are still aligned.

[0031] (With or without underfill material) Separation layer 410 can be disposed between passivation layer 760 and the lower surface 631 of RFIC 110. When separation layer 410 is composed of underfill, the underfill does not form an interface with the active die region 737 of RFIC 110, thus avoiding signal loss that would otherwise be caused by the interface. Additionally, the possibility of oscillation is reduced compared to the connection structure 600 of FIG. 6. This is because the active die side region 737 is located further away from ground plane 440 (not shown in FIG. 7, but located between the surface 453 of substrate 150 and separation layer 410 as seen in FIGS. 4A, 4B, 5, and 7B). Further, a ground plane that acts as a ground for the beamforming circuit within RFIC 110 can exist on the lower surface 631 of RFIC 110, further reducing the risk of oscillation.

[0032] FIG. 7B is a cross-sectional view of an exemplary portion of an antenna device 100 showing an exemplary extended connection structure including the dual via-type connection of FIG. 7A. The connection structure 700a includes the above-described connection structure 700, with first and second ground connection joints 720g1 and 720g2 on both sides, collectively forming a GSG connection set 720. Each of the ground connection joints 720g1 and 720g2 can have the same type of structure and similar dimensions as the signal connection joint 720s. Each of the ground connection joints 720g1 and 720g2 can electrically connect a respective local region of the ground plane 708 of the RFIC 110 to a connection point on the ground plane 440. A local surface finish layer 756 can be applied to the ground plane 440 to assist in adhering the ground connection joints 720g1, 720g2 to the ground plane 440.

[0033] FIG. 7B also shows a redistribution layer (RDL) 788 that can exist between the RFIC 110 and the ground plane 440. The RDL 788 can be used to connect circuit points within the RFIC 110 and / or circuit points of different RFICs 110, typically to route DC bias between circuit points. The RDL 788 is formed over a region of the protective layer 760 and separates the protective layer from the ground plane 440. A connection joint 790, which can have the same type of structure as the signal connection joint 720s, can connect the I / O pad 792 of the RFIC 110 to the RDL 788. The RDL 788 extends horizontally and can connect to another I / O pad of the RFIC 110 (not shown) or a different RFIC 110 via another connection joint 790 to route signals / DC voltages between different circuit points of the RFIC(s) 110. If at least one additional RDL 788 is added to the configuration of the antenna device 100, an additional passivation layer 760 can be disposed on one or both sides of each additional RDL to provide the necessary separation between the RDLs.

[0034] FIG. 8A shows an exemplary arrangement 800a of the antenna element feeding point positions with respect to the RFIC connected within the antenna device 100. In this example, the RFIC 110 is connected to four antenna elements 120-a, 120-b, 120-c, and 120-d arranged as part of a triangular lattice with respect to the center point 123 of the antenna element. The center point 123 can also be referred to herein as the phase center 123 of each antenna element interchangeably. The RFIC 110 is arranged as part of a rectangular lattice as shown previously in FIGS. 1 and 2. Each of the antenna elements 120-a to 120-d is exemplified as a circular patch element having a slit 811 (elongated slot) extending from an open end at the periphery of the antenna element towards the closed end towards the center point 123. The antenna elements 120-a to 120-d are each connected to the RFIC 110 from feeding points 122-a, 122-b, 122-c, and 122-d. Note that the "x" within the "○" indicating the feeding point 122 represents any one of the I / O pads of the RFIC 110, such as the I / O pads 412, 512, 624, or 712 described above.

[0035] Instead of feeding each antenna element 120 at its center point 123, the feeding points 122-a to 122-d in each group of the four antenna elements connected to the RFIC 110 are each offset from the center point 123 in different directions, and the slits 811 are aligned corresponding to different directions respectively. The patch design may be the same for each of the four antenna elements 120-a to 120-d, but may also be rotated in 90-degree units between the antenna elements. This rotation in the patch design from the antenna elements 122-a to 122-d advantageously forms pattern diversity as well as circularly polarized waves with a low axial ratio. The position and dimensions of each slit 811, as well as the relative positions of the adjacent feeding points 122, are designed to form circularly polarized waves with respect to the corresponding antenna element 120. For this purpose, the length of each slit 811 may be in the range of 1 / 4 to 3 / 4 of the radius of the antenna element 120. In one example, each slit 811 is about 2 / 3 of the radius. The feeding points 122-a to 122-d are each offset laterally from the side of the adjacent slit 811 close to the closed end.

[0036] The local coordinate system of the RFIC 110 having a rectangular footprint can be defined with the center point 113 as the origin, an X-axis parallel to the upper and lower sides of the rectangular footprint, and a Y-axis parallel to the left and right sides. The local coordinate system of each antenna element 120-a to 120-d may be defined with the center point 123 as the origin, an x-axis parallel to the X-axis, and a y-axis parallel to the Y-axis. The antenna elements 120-a and 120-b have the same +X coordinate for the center point 123 and are arranged in the upper row separated by X1 in the column direction. The antenna elements 120-c and 120-d are in the lower row at the same -Y level, separated by X1 in the column direction, and separated from the upper row by Y1. The slits 811 and the corresponding feeding points 122-a to 122-d of the antenna elements 120-a to 120-d are rotated by 90°. Therefore, the feeding points 122-a, 122-b, 122-c, and 122-d are located in different quadrants of the local x-y coordinate system. In this example, the feeding points 122-a to 122-d are in the lower left (-x, -y), upper left (+y, -x), upper right (+x, +y), and lower right (+x, -y) quadrants, respectively. Each feeding point 122 is offset by Δx and Δy in the x and y directions from the respective center point 123. In the y direction, in each column, the feeding points have a y-axis variation of 2Δy. In the x direction, there is a column-to-column variation of 2Δx compared to supplying all the antenna elements to the center point 123.

[0037] In the arrangement of FIG. 8A, the rotation of the patch design that causes a variation in the position of the feeding point 122 from quadrant to quadrant with respect to the center 123 of the antenna element 120 improves the axial ratio and pattern diversity. However, since the feeding points of each column vary in the y direction, the layout of the beamforming circuit in the RFIC 110 is asymmetric, making the circuit layout and packaging more complex and difficult.

[0038] FIG. 8B shows another exemplary arrangement 800b of the antenna element feeding point positions for the RFIC 110 connected within the antenna device 100. In this case, unlike the arrangement 800a where the feeding points 122 in each column have the same Y coordinate, this allows for a simpler beamforming circuit layout. Similar to the arrangement 800a, the RFIC 110 is connected to four antenna elements 120-a, 120-b, 120-c, and 120-d that can be assumed to have the same footprint and relative position as in FIG. 8A for comparison. Each feeding point 122 is also shown as being offset by Δx and Δy from the adjacent center point 123. However, in the device 800b, in the top row, the feeding point 122-a is in the upper left quadrant and the feeding point 122-b is in the upper right quadrant. Thus, the X interval between these feeding points is (X1 + 2Δx), which is 2Δx wider than that of the arrangement 800a. Similarly, in the lower row, the feeding point 122-c is in the lower left quadrant and the feeding point 122-d is in the lower right quadrant, and the X interval between these feeding points is also (X1 + 2Δx). Further, in the Y direction, the interval between the upper and lower row feeding points 122 is uniform (Y1 + 2Δy). It should also be noted that the position of the slit 811 with respect to the quadrant position of the feeding point 122 is the same as that of the arrangement 800a.

[0039] Therefore, for a given RFIC 110 having the I / O pad positions according to the arrangement 800b, the I / O pad positions (corresponding to the feeding point 122 positions) are further apart in both the X and Y directions compared to the interval between the center points 123. This also applies to the arrangement 800a when considering the maximum X and Y intervals between any two feeding points 122. Thus, assuming the same beamforming circuit within the RFIC 110 for the arrangement 800b versus 800a, the same rectangular footprint of the RFIC 110 can be typical.

[0040] FIG. 8C shows yet another exemplary arrangement 800c of the antenna element feeding point positions with respect to the RFIC 110 connected within the antenna device 100. In this embodiment, the same relative positions of the antenna elements 120-a to 120-d, i.e., the antenna element spacing within the column of X1 and the inter-column spacing of Y1, can be assumed. However, in configuration 800c, the feeding points 122-a, 122-b, 122-c, and 122-d are arranged in the lower right, lower left, upper right, and upper left quadrants, respectively. Thereby, the X-spacing (X1 - 2Δx) between the feeding points 122-a and 122-b in the uppermost row, and between the feeding points 122-c and 122-d in the lowermost row becomes smaller. Further, the inter-column Y-spacing between the feeding points 122 is also reduced to (Y1 - 2Δy). Thus, in configuration 800c, the corresponding I / O pads (the "x" within the feeding point 122 represents any one of the I / O pads 412, 512, etc.) can use a smaller rectangular footprint of the RFIC 110 if the packaging of the beamforming components permits.

[0041] Thus, the aspects of configurations 800a, 800b, and 800c can be summarized as follows. Each of the RFICs 110 includes a plurality of N I / O pads connected to corresponding plurality of feeding points of a group of N circularly polarized antenna elements. The first antenna element of the group has at least one feeding point offset in a first direction from its center point, and the second antenna element of the group has at least one feeding point offset in a second different direction from its center point, where the first and second directions are defined with respect to a common coordinate system. Each group may be a group of four antenna elements connected to a single RFIC. If there are four antenna elements in each group, each of the four antenna elements has a feeding point offset from the center of each respective antenna element in a direction different from any of the other antenna elements among the four antenna elements with respect to a common coordinate system. Each of the antenna elements of the group can have the same design configuration having a slit and at least one feeding point offset laterally from an edge of the slit to generate a circularly polarized wave for transmission and / or reception operations. Each of the second to fourth antenna elements among the four antenna elements of the group can be rotated by K×90° with respect to the first antenna element of the group, where K is in the range of 1 to 3 and is different for each of the second to fourth antenna elements.

[0042] FIG. 9 is a diagram showing an exemplary layout of a beamforming circuit in an RFIC 110 having I / O pads arranged according to the arrangement 800b of FIG. 8B. In this example, the RFIC 110 has four GSG I / O pad connection sets (the "GSG sets") 940-a, 940-b, 940-c, and 940-d, each having a signal I / O pad (the "S pad") 912 and a pair of ground ("G") pads 408 on both sides of the S pad 912. Thus, each of the GSG sets 940-a to 940-d can be a set of first and second linearly aligned ground pads and a signal pad that collectively forms an elliptical profile having a major axis and an orthogonal minor axis, where the major axis is substantially parallel to the left and right edges of each respective RFIC 110.

[0043] Each S pad 912 may be configured as any one of the I / O pads 412, 512, 624, or 712 described above, and each G pad 408 may be configured as any one of the G pads 408 in FIG. 4. Each S pad 912 is connected to the corresponding power supply points 122-a to 122-d using any one of the connection structures described above for the I / O pads 412, 512, etc. Therefore, each S pad 912 is aligned with each of the power supply points 122-a, 122-b, 122-c, and 122-d. In each GSG set 940-a to 940-d, the G pad 408 and the S pad 912 may be linearly aligned in the Y direction.

[0044] The first output amplifier region 920-1 may be arranged between the GSG sets 940-a and 940-b, and the second output amplifier region 920-2 may be arranged between the GSG sets 940-c and 940-d. Each GSG set 940-a to 940-d can be connected to the output or input of each amplifier 903 in the adjacent amplifier region 920-1 or 920-2. In the illustrated example, the amplifier 903 is a power amplifier during transmission, and each GSG set is connected to the output port of the amplifier 903. In other examples, some of the amplifiers 903 are PAs and other amplifiers 903 are LNAs. In the latter case, any given GSG set 940 can be connected to the input of the LNA.

[0045] The circuit region 950 having an additional beamforming circuit may be arranged outside the regions 920-1 and 920-2. For example, each amplifier 903 can be connected to respective bandpass filters 905 and phase shifters 907 within the circuit region 950. Generally speaking, the amplifier 903 cooperates with the beamforming circuit within the circuit region 950 to adjust (received from the antenna element 120 / output to the antenna element) the signals input / output from / to the GSG set 940 (e.g., amplification, phase shift, filtering, etc.). The circuit region 950 can further include at least one combiner / divider 910 composed of one or more RF couplers (e.g., 3dB directional couplers) for combining and / or splitting the signals received / transmitted from / to at least two antenna elements 120.

[0046] The GSG sets 940-a and 940-d are arranged adjacent to the upper left corner and the lower right corner of the RFIC 110, respectively. These positions may be set as close as possible to the respective left and right edges of the RFIC 110 (as seen in FIG. 9) as long as the design rules of the foundry manufacturing the RFIC 110 permit. The GSG sets 940-a and 940-b may be at the same Y level adjacent to the upper edge of the RFIC 110. The GSG sets 940-c and 940-d may be at the same -Y level adjacent to the lower edge. The GSG set 940-b may have an X-direction center coordinate approximately midway between the GSG sets 940-c and 940-d. Similarly, the GSG set 940-c may have an X-direction center coordinate approximately midway between the GSG sets 940-a and 940-b. When each GSG set 940 is aligned with the corresponding feeding point 122 of the antenna element 120 as described above, the positions of the GSG sets 940 are aligned with the triangular grid points 123 of the antenna element 120 as shown in FIG. 2. This configuration is different from a standard RFIC chip that typically has all I / O pads arranged symmetrically adjacent to opposite edges of their rectangular footprint. For example, in a standard RFIC chip, the GSG set 940-c is arranged at the lower left corner and the GSG set 940-b is arranged at the upper right corner. The arrangement in FIG. 9 that moves a portion of the GSG sets inward from the corners enables alignment of the GSG sets with the antenna feeding point 122.

[0047] Although the technology described herein has been particularly shown and described with reference to its exemplary embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the subject matter defined by the following claims and their equivalents.

Claims

1. An antenna device (100), comprising: A first component layer disposed in a first plane having a first grid arrangement (204), the first component layer including a plurality of radio frequency integrated circuit chips (RFICs) (110), each of the RFICs including a beamforming circuit (920, 950); and A second component layer including a plurality of antenna elements (120) disposed in a second plane parallel to the first plane and having a second different grid arrangement (202) and superimposed on the first component layer; Each of the first and second grid arrangements is a two-dimensional shape, the first grid arrangement is rectangular, the second grid arrangement is non-rectangular, or vice versa, and each antenna element has a respective feeding point (122) connected to one of the input / output (I / O) pads (412, 512, 612, 712) of the RFIC, and each of the I / O pads is aligned with the connected feeding point along an axis (425) orthogonal to the first and second planes. Antenna device (100).

2. The antenna device (100) according to claim 1, wherein the first grid arrangement (204) is rectangular and the second grid arrangement (202) is triangular.

3. Further comprising an antenna substrate (150) between the first component layer and the second component layer, and a plurality of vias (302) extending through the antenna substrate, each via connecting one of the antenna elements to one of the plurality of I / O pads of the RFIC. Antenna device (100) according to claim 1.

4. The plurality of I / O pads are flip-chip I / O pads (612), each flip-chip I / O pad being electrically connected to one of the vias via a flip-chip electrical connection joint (520s), and the active die side (637) of each RFIC facing the antenna substrate. Antenna device (100) according to claim 3.

5. The flip-chip electrical connection joint is surrounded by an underfill layer (410) between the antenna substrate and the second component layer. The antenna device according to claim 4, further comprising a polymer overcoat layer between the second component layer and the underfill layer.

6. The antenna device (100) according to claim 3, wherein the active die side (737) of each RFIC faces the antenna substrate.

7. The plurality of vias are a plurality of first vias (702). The antenna device further comprises a plurality of second vias (732) each extending from the non-active side to the active side of one of the RFICs among the RFICs, and a plurality of electrical connection joints (720s) each connecting an end of a first via to an end of a second via. The antenna device (100) according to claim 6.

8. The antenna device (100) according to claim 7, wherein each of the plurality of electrical connection joints is surrounded by an underfill layer (410) between the antenna substrate and the second component layer.

9. Each of the RFICs includes a plurality of N I / O pads (412, 512, 612, 712) connected to corresponding plurality of feeding points of N of the antenna elements. The antenna device (100) according to claim 1, lacking any transmission line oriented parallel to the first and second planes for connecting any RFIC in the first component layer to any antenna element in the second component layer.

10. Each of the RFICs includes a plurality of N I / O pads (412, 512, 612, 712) connected to corresponding plurality of feeding points of N of the antenna elements. Each of the antenna elements is a circularly polarized patch antenna element. Among the plurality of antenna elements, the first antenna element has at least one feeding point (122-a) offset in a first direction from the center (123) of the first antenna element, and among the plurality of antenna elements, the second antenna element has at least one feeding point (122-b) offset in a second direction different from the first direction from the center (123) of the second antenna element, and the first and second directions are defined based on a common coordinate system. The antenna device (100) according to claim 1.

11. The antenna element is arranged in a group of four antenna elements (120-a, 120-b, 120-c, 120-d) connected to a single one of the RFICs (110), and in each of the groups, each of the four antenna elements has a feeding point offset from the center of the respective antenna element in a direction different from any of the other antenna elements among the four antenna elements based on a common coordinate system. The antenna device (100) according to claim 1.

12. Each of a group of the antenna elements has the same design configuration including a slit (811) and at least one feeding point offset laterally from an edge of the slit to form a circularly polarized wave for transmission and / or reception operations. Each of the second to fourth antenna elements among a group of the four antenna elements (120-b, 120-c, 120-d) is rotated by K×90° with respect to the first antenna element (120-a) of the group, where K is in the range of 1 to 3, and is different for each of the second to fourth antenna elements. The antenna device (100) according to claim 11.

13. The antenna device (100) according to claim 1 further includes a ground plane (340) between the first component layer and the second component layer.

14. The first grid arrangement (204) is rectangular, the second grid arrangement (202) is triangular, and the antenna device is An antenna substrate (150) between the first component layer and the second component layer, A plurality of vias (302) extending through the antenna substrate, each of the vias connecting a feeding point (122) of one of the antenna elements to one of the I / O pads, and a plurality of vias, The antenna element is arranged in a group of a plurality of N antenna elements (120-a, 120-b, 120-c, 120-d) each connected to a single one of the RFICs, and in each group, each of the N antenna elements has a feeding point (122-a, 122-b, 122-c, 122-d) offset from the center (123) of the respective antenna element in a direction different from the feeding point offset direction of any of the other antenna elements of the N antenna elements with respect to a common coordinate system. The antenna device (100) according to claim 1.

15. The antenna device (100) according to claim 14, wherein N is equal to 4.

16. The antenna device (100) according to claim 14, further comprising a ground plane (340) between the antenna substrate and the second component layer.

17. Each of the RFICs includes first, second, third, and fourth ground-signal-ground I / O pad connection sets ("GSG sets") (940-a, 940-b, 940-c, 940-d), the signal I / O pads of each GSG set are connected to the feeding points of the respective antenna elements, and the first and second ground pads of each GSG set are each connected to the ground plane. The antenna device (100) according to claim 14.

18. Each RFIC of the RFICs has a rectangular profile with an upper edge, a lower edge, a left edge, and a right edge, the X direction is parallel to the upper and lower edges, and the Y direction is parallel to the left and right edges. The first GSG set (940-a) is arranged at the upper left corner of each RFIC of the RFICs, and the fourth GSG set is arranged at the lower right corner of each RFIC of the RFICs. The second GSG set (940-b) has a Y coordinate close to the upper edge and an X coordinate approximately in the middle of the X coordinates of the third GSG set and the fourth GSG set. The third GSG set (940-c) has a Y coordinate close to the lower edge and an X coordinate approximately in the middle of the X coordinates of the first GSG set, the second GSG set, and the fourth GSG set, for the antenna device (100) according to claim 17.

19. Each of the GSG sets is a set in which the first and second ground pads (408) and the signal pads (912) are linearly aligned, and the pads collectively form a rectangular profile having a major axis and an orthogonal minor axis, and the major axis is substantially parallel to the left edge and the right edge of each of the RFICs, for the antenna device (100) according to claim 18.

20. The beam forming circuit is a millimeter wave front end circuit, for the antenna device (100) according to claim 14.

21. An antenna device (100), A first component layer including a plurality of radio frequency integrated circuit chips (RFICs) (110) arranged in a first plane having a first grid arrangement (204), each of the RFICs including a beam forming circuit (920, 950), the first component layer; A second component layer including a plurality of antenna elements (120) arranged in a second plane parallel to the first plane and having a second different grid arrangement (202), which is superimposed on the first component layer. Each of the first and second grating arrangements has a two-dimensional shape, and each of the antenna elements has a respective feeding point (122) connected to one input / output (I / O) pad (412, 512, 612, 712) of the RFIC. Each of the I / O pads is aligned with the connected feeding point along an axis (425) orthogonal to the first and second planes, the antenna device (100).

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