Integration of EGB structures with enhanced isolation in millimeter-wave multi-layer embedded packaging technology

Abstract

The present disclosure generally includes the integration of an EGB structure with enhanced isolation in a millimeter-wave multi-layer embedded packaging technology. The packaged radar includes: stacked layers; a ground plane associated with at least one stacked layer; a transmitting antenna and a receiving antenna associated with at least one stacked layer; and an electromagnetic bandgap structure between the transmitting antenna and the receiving antenna, the electromagnetic bandgap structure is used to isolate the transmitting antenna from the receiving antenna, and the electromagnetic bandgap structure includes a basic unit, the basic unit forming adjacent pillars, each of the adjacent pillars coupled to the ground plane, and each basic unit including a conductive planar element and a pillar-shaped element coupled to the conductive planar element.

Description

Technical Field

[0001] The present invention generally relates to radio frequency electronic devices and, in a particular embodiment, to radio frequency electronic device packages and methods of forming the same. Background Art

[0002] A packaged radio frequency device utilizing multiple antenna elements, such as a radar sensor, can be configured in a portable device, for example, as an interface for controlling the functionality of the device. Many portable devices must be small, and therefore embedded radar systems with reduced form factors are desirable. Antenna elements embedded in the package of a radio frequency ("RF") radar system occupy a significant percentage of the total package size. Therefore, minimizing antenna locations and corresponding RF device layout size can be a priority during package design for an integrated RF multi-antenna system. Summary of the Invention

[0003] According to an embodiment, a packaged radar includes: a plurality of stacked layers; a ground plane associated with at least one of the stacked layers; a transmitting antenna and a receiving antenna associated with at least one of the stacked layers; and an electromagnetic bandgap structure disposed between the transmitting antenna and the receiving antenna and configured to isolate the transmitting antenna from the receiving antenna, the electromagnetic bandgap structure including a plurality of basic units forming a plurality of adjacent pillars, each of the plurality of adjacent pillars being coupled to the ground plane, and each basic unit including a conductive planar element and a pillar element coupled to the conductive planar element. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] For a more complete understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0005] Figure 1A is a half-side view of an electromagnetic bandgap ("EBG") structure having a single rectangular patch;

[0006] Figure 1B is a semi-side view of an EBG structure with a single circular patch;

[0007] Figure 1C is with Figure 1A S-parameter diagram associated with the EBG structure;

[0008] Figure 1D is with Figure 1A and Figure 1B S-parameter phase diagram associated with the EBG structure;

[0009] Figure 2 is a semi-side view of a row of circular EBG structures;

[0010] Figure 3 is a half-side view of a row of rectangular EBG structures;

[0011] Figure 4 is a half-side view of two rows of rectangular EBG structures;

[0012] Figure 5 is a half-side view of a rectangular EBG structure with patches at two metal layer locations according to an embodiment;

[0013] Figure 6 is a half-side view of a row of rectangular EBG structures with patches at two metal layer locations according to an embodiment;

[0014] Figure 7 is a half-side view of a row of rectangular EBG structures with patches at two metal layer locations and associated metal ground plane features according to an embodiment;

[0015] Figure 8A is a cross-sectional view of a packaged radar system having a transmit antenna and a receive antenna isolated using an EBG structure at a first depth according to a first embodiment;

[0016] Figure 8B is a cross-sectional view of a packaged radar system having a transmit antenna and a receive antenna isolated using an EBG structure at a second depth according to the first embodiment;

[0017] Figure 9A is a cross-sectional view of a packaged radar system having a transmit antenna and a receive antenna isolated using an EBG structure at a first depth according to a second embodiment;

[0018] Figure 9B is a cross-sectional view of a packaged radar system having a transmit antenna and a receive antenna isolated using an EBG structure at a second depth according to a second embodiment;

[0019] Figure 10 is a cross-sectional view of a packaged radar system with isolated transmit and receive antennas using an EBG structure according to a third embodiment;

[0020] Figure 11A is a plan view of a packaged radar system having one transmit antenna and three receive antennas;

[0021] Figure 11B is a plan view of a packaged radar system having one transmit antenna isolated from three receive antennas using multiple EBG structures according to one embodiment;

[0022] Figure 12A is with Figure 11AAn isolated diagram associated with a packaged radar system;

[0023] Figure 12B is with Figure 11B An isolated diagram associated with a packaged radar system;

[0024] Figures 13 to 16 is a plan view of a packaged radar system including various isolated antenna configurations according to an embodiment; and

[0025] Figure 17 is a flow chart of a method of forming a packaged radar system having transmit and receive antennas isolated using at least one EBG structure, according to one embodiment. DETAILED DESCRIPTION

[0026] Electromagnetic bandgap ("EBG") structures are a class of 2D and 3D resonant defects etched in the ground plane of RF circuits for the purpose of reducing the size of passive components (e.g., antennas or filters) and / or reducing mutual coupling in array configurations.

[0027] In many radar applications, including packaged radar applications, the transmit antenna is very close to one or more receive antennas. The transmit antenna and receive antennas can share the same ground plane, which results in strong coupling between at least the transmit antenna and its nearest receive antenna.

[0028] According to an embodiment, coupling between the transmit and receive antennas is reduced by inserting a wall comprising a plurality of elementary artificial magnetic conductors ("AMC" cells, or cells) therebetween. These cells behave like perfect magnetic conductors, with the reflection coefficient having a phase ranging from -90° to +90°. In this manner, the cells present a high-impedance boundary without affecting (cancelling) the electric field distribution of the coexisting antennas.

[0029] Figure 1A 1 is a semi-side view of a portion of an EBG structure 102, which takes the form of a basic AMC cell having a planar element 104 and a corresponding cylindrical element (or rod) 106 fixed thereto. In packaged applications, the planar element 104 and the rod 106 are typically coupled to a ground plane. The planar element 104 and the rod 106 can be coupled to the ground plane directly, such as via one or more other cells vertically stacked with the cell in question, or indirectly.

[0030] The planar element (or patch) may have any shape, such as: oval, circular or polygonal (e.g. Figure 1A rectangle in the figure).

[0031] Figure 1Bis a semi-side view of an AMC unit having a circular patch 110 and a corresponding rod 112.

[0032] Figure 1C is with Figure 1A Figure 11 shows an S-parameter graph associated with an EBG structure 102. The return loss of the AMC cell is close to 0 dB (perfect reflection, as shown in curve 116), but the reflected phase is not the typical 180° phase of a metal surface. Instead, the reflected phase 118 ranges from 53° at 50 GHz to -88° at 70 GHz. This means that over the bandwidth of interest (e.g., 60 GHz), the AMC cell behaves like an artificial magnetic conductor.

[0033] Figure 1D is consistent with Figure 1 and Figure 2 Figure 12 shows the S-parameter phase plot associated with an EBG structure. As expected, any patch shape can support AMC behavior. For example, curve 122 represents the reflection phase of a circular EBG structure with a patch diameter of 400 μm and a cell size of 500 μm. Curve 124 shows a similar reflection phase for a square EBG structure with a patch length of 400 μm and a cell size of 525 μm.

[0034] Figure 2 is a semi-side view of a row 202 of base units, each having a circular patch 204A, 204B, 204C, and 204D, and corresponding rods 206A, 206B, 206C, and 206D extending from the circular patch downwardly to a ground plane 208 .

[0035] Figure 3 is a half-side view of a row 302 of cells showing individual rectangular patches 304A, 304B, 304C, and 304D, and corresponding rods 306A, 306B, 306C, and 306D extending from the rectangular patches down to a ground plane 308 .

[0036] Figure 4 4 is a half-side view of an array having two rows 402 of cells, showing a first row of individual rectangular patches 404A, 404B, 404C, and 404D, a second row of individual rectangular patches 404E, 404F, 404G, and 404H, and corresponding rods 406A, 406B, 406C, and 406D arranged in the first row, and corresponding rods 406E, 406F, 406G, and 406H arranged in the second row. The rods extend from the rectangular patches down to a ground plane 408.

[0037] Figure 55 is a semi-side view of a portion of an EBG structure 502, which is in the form of a column consisting of two basic units stacked on top of each other. Each unit has a rectangular patch, and the two patches are placed at different positions along the main direction of the column. The patch of the bottom unit is electrically coupled to the rod of the top unit. For example, the bottom unit and the top unit are fixed to each other. The patches of the units can have the same or different sizes, and / or the same or identical shapes. Although Figure 5 A column comprising two units is shown, but a given column may be formed from any number of overlapping units, or even from a single unit which itself exhibits the same Figure 1A Columnar configuration shown in the figure.

[0038] As previously discussed, smaller cell sizes of EBG structures for isolating a transmit antenna and one or more receive antennas in packaged radar applications are desired. In one example, for the same AMC behavior, the cell size of EBG structure 102 may have a length of 525 μm on a side, and the cell size of EBG structure 502 may have a length of only 400 μm on a side.

[0039] In an example application of a packaged radar with four conductive layers and three laminate layers, the composition of the pillars of EBG structures 102 and 502 is compared below. The square patch on the fourth conductive layer for EBG structure 102 is 425 μm by 425 μm, while the square patch 504 on the fourth conductive layer for EBG structure 502 can be reduced to 250 μm by 250 μm. The pillar of EBG structure 102 can include a single cell and can terminate on the third conductive layer (the third conductive layer is coupled to ground), while the pillar of EBG structure 502 can include several cells, including a cell with patch 508 on the third conductive layer, which has dimensions of 250 μm by 250 μm. For EBG structure 102, because the top cell terminates on the third conductive layer, the pillar may not be able to reach the first and second conductive layers. For the EBG structure 502, the second conductive layer is not used, but the pillars terminate at the first conductive layer (which is coupled to ground). Figure 8A 、 Figure 8B 、 Figure 9A 、 Figure 9B and Figure 10 Further illustration and description are given of a packaged radar device having multiple conductive layers and layer stacks.

[0040] Figure 6 is a semi-side view of a row 502A of columns, each column having two units stacked on top of each other. A single column is essentially as described above with respect to Figure 5 As described. Thus, the first column includes: a first patch 504A, a rod 506A coupled to patch 504A, and a second patch 508A, wherein the corresponding rod of patch 508A terminates in a ground plane 510. The second column includes: a first patch 504B of the second unit, a corresponding rod 506B, and a second patch 508B, wherein the corresponding rod of the second patch 508B terminates in a ground plane 510. The third column includes: a first patch 504C, a corresponding rod 506C, and a second patch 508C, wherein the corresponding rod of the second patch 508C terminates in a ground plane 510. The fourth column includes: a first patch, an associated rod 506D, a second patch, and a corresponding rod terminating in an associated ground plane 510. As in Figure 6 As shown in FIG, two different rods in a given column can have different lengths. Patches 504A, 504B, 504C, 504D can be positioned at the same height and can be associated with a given conductive layer (e.g., the fourth conductive layer), for example, at the height of these patches. Patches 506A, 506B, 506C, and 506D can be positioned at the same height and can be associated with another given conductive layer (e.g., the third conductive layer), for example, at the height of these patches. Ground plane 510 can be associated with a corresponding conductive layer (e.g., the first conductive layer) (e.g., which can be positioned at the height of ground plane 510).

[0041] Figure 7 FIG. 5 is a half-side view of a row 502B of pillars having cells with their patches at two metal layer locations, and associated conductive layer features 512A and 512B, according to an embodiment. A single pillar is substantially as described above with respect to FIG. Figure 5 Features 512A and 512B correspond to opposite edges of a slot arranged in the conductive layer to receive a pillar therethrough. For example, the pillar comprises a patch positioned at the same height as the conductive layer. For example, if required for a particular application, features 512A and 512B can be used to further enhance the AMC behavior of row 502B of the rectangular EBG structure. The conductive layer including features 512A and 512B can include a ground plane.

[0042] exist Figures 5 to 7The EBG structure shown in FIG can be modified as desired. For example, although square patches are shown, other patches such as circular or bell-shaped patches may be used. In general, any polygonal shape may be used. Although only one additional square patch is shown associated with the third conductive layer, additional square or additional circular patches may be used in association with any conductive layer. Although only an EBG structure with a single row of pillars is shown, multiple rows of pillars may be used. Although a ground plane is shown on the first conductive layer, other levels of conductive layers may be used to couple the rods of the AMC unit to ground. The rods of the AMC unit may be isolated from or coupled to any conductive layer in the packaged radar, as required for a given application.

[0043] Figure 8A FIG2 is a cross-sectional view of a packaged radar system 800A having a transmit antenna 802 and a receive antenna 806 isolated using an EBG structure having adjacent posts (with post 804A visible) disposed between respective regions of transmit antenna 802 and receive antenna 806. Packaged radar system 800A includes a plurality of stacked layers 808, 810, and 812, and a plurality of conductive layers including a first conductive layer 820, which can be used as a ground plane, a second conductive layer 818, a third conductive layer 816, and a fourth conductive layer, which can be used to form the topmost package of transmit antenna 802 and receive antenna 806, and preferably, post 804A. The conductive layers can include patterned metal layers that are selectively electrically connected to or isolated from the posts of the EBG structure. The conductive layers themselves can be interconnected with vias such as via 822A, which interconnects a portion of the fourth conductive layer with a portion of the third conductive layer, and via 822B, which also interconnects a portion of the fourth conductive layer with a portion of the third conductive layer. The packaged radar system 800A also includes a radar transmit and receive integrated circuit 824, which is fixed to the bottom surface of the first stack 812 and the first conductive layer 820. The integrated circuit 824 can be connected to the first stack 812 by passing through the conductive layer 820 (at Figure 8A Additional vias (not shown) are electrically connected to the various conductive layers of packaged radar system 800A. A ball grid array including solder balls 814A and 814B may also be affixed to the bottom surface of first stack 812 and first conductive layer 820 to enable the radar system to be used with other components in a larger system, including other components such as memory or processing components.

[0044] Column 804 itself comprises a single unit cell, whose patch is positioned at the same depth as the transmit and receive antennas, i.e., in this embodiment, at the top surface of top layer 808. The stem of the unit cell is connected to ground plane 820. In general, the planar elements of the EBG structure can be positioned at any depth within the packaged radar, although in a preferred configuration, the topmost patch of the EBG structure is positioned at a depth below or at the same depth (e.g., higher) than the transmit and receive antennas. In other words, the topmost patch of the EBG structure (i.e., the patch closest to the top surface of the packaged radar) is at the same or higher elevation as the transmit and receive antennas. Additionally, while the antenna has been illustrated as being positioned on the top surface of the package, in other embodiments, the antenna can be positioned within the package itself.

[0045] exist Figure 8A 800A, transmit antenna 802 and receive antenna 806 are associated with upper stackup 808. However, stackup 808, transmit antenna 802, and receive antenna 806 may be placed in an intermediate position within packaged radar system 800A, or may even be placed in a bottom position relative to the main upper surface of packaged radar system 800A. Figure 8B In the embodiment, the stack layer 808 is shown in the middle layer position. Figure 8B , transmit antenna 802 and receive antenna 806 are positioned at a lower height within packaged radar system 800A than the planar patch of unit 804A. Figure 8B , the stack layer 810 has been correspondingly moved to the upper position.

[0046] Although Figure 8A and Figure 8B The pillars of the EBG structure in may include a single AMC unit as shown to effectively isolate the transmit antenna 802 from the receive antenna 806, but the size of the patch for effective isolation may not be optimal for use in a compact package radar system. Figure 9A A more compact packaged radar system is shown in FIG and described below using an EBG structure with smaller sized patches associated with multiple conductive layers.

[0047] Figure 9A FIG is a cross-sectional view of a packaged radar system 800B having a transmit antenna 802 and a receive antenna 806 isolated using an EBG structure 804B according to a second embodiment. Figure 9A In FIG, only the pillars of the EBG structure are changed, and therefore, for convenience, not all reference numerals used to identify the stacked layers, conductive layers, and other features of the packaged radar system 800B are replicated. Figure 9AIn FIG, the pillar 804B of the EBG structure includes a plurality of stacked units. For example, the first top package of the pillar is associated with the fourth conductive layer, and the second package of the pillar is associated with the third conductive layer. Figure 9A The sizes of the patches in the column 804B are all smaller than those in the column 804B described above. Figure 8A and Figure 8B 804A in the embodiment of the present invention, without sacrificing any isolation performance. In other words, although the coverage area of ​​radar system 800B may be smaller than the coverage area of ​​radar system 800A, the transmit antenna 802 and the receive antenna 806 in both radar system 800A and radar system 800B are isolated from each other at the same level of performance.

[0048] exist Figure 9A 800A, transmit antenna 802 and receive antenna 806 are associated with upper stackup 808. However, stackup 808, transmit antenna 802, and receive antenna 806 may also be placed in an intermediate position within packaged radar system 800A, or even in a bottom position relative to the main upper surface of packaged radar system 800A. Figure 9B In the embodiment, the stack layer 808 is shown in the middle layer position. Figure 9B , transmit antenna 802 and receive antenna 806 are located lower within packaged radar system 800A than the uppermost planar patch of unit 804B. Figure 9B , the stack layer 810 has been correspondingly moved to the upper position.

[0049] Although Figure 8A 、 8B The packaged radar system shown in 9A and 9B is sufficient for many applications, but other stacked layers or layers external to the packaged radar system may also be used. These layers may generate internal reflections that increase coupling between the transmit antenna and the receive antenna. Such a packaged radar system may be used in Figure 10 is shown in and described below.

[0050] Figure 10 FIG is a cross-sectional view of a packaged radar system 800C with isolated transmit antenna 802 and receive antenna 806 using an EBG structure according to a third embodiment. For convenience, not all reference numerals used to identify stacked layers, conductive layers, and other features of the packaged radar system 800C have been changed from those previously described. Figure 8A 、 Figure 8B 、 Figure 9A and Figure 9BThe packaged radar system 800C includes: an additional layer 826, which may include an additional layer stack on top of the fourth conductive layer, the additional layer stack may or may not include an additional conductive layer, or the additional layer 826 may include a layer outside the packaged radar system, or the additional layer 826 may include an air pocket layer below layer 828. The packaged radar system 800C also includes an additional layer 828, which may include a glass, acrylonitrile butadiene styrene ("ABS"), or other plastic layer. While these layers may be useful in many applications (for example, layer 826 and layer 828 may include a radome), they may cause reflections from the transmit antenna 802 to the receive antenna 806. For example, the reflection may occur at the interface 830 between layer 826 and layer 828, and the reflection may occur at the surface 832 of layer 828. In Figure 10 A single AMC unit 804C is shown in FIG. 8 , which can be used with the previously described Figure 8A 、 Figure 8B 、 Figure 9A or Figure 9B The single AMC unit shown in any of the figures is identical. Figure 10 The positioning of the transmit antenna, receive antenna, and corresponding stack layers shown in FIG. 1 may be associated with a topmost stack layer position, a middle stack layer position, or a bottommost stack layer position.

[0051] Figure 11A 1 is a plan view of a packaged radar system 1100A having one transmit antenna 1102 and three receive antennas 1104A, 1104B, and 1104C. The packaged radar system 1100A may have coupling between the transmit antenna 1102 and one or more receive antennas 1104A, 1104B, and 1104C. Figure 11A In the plan view shown in , each of the transmitting and receiving antennas is, for example, part of a fourth conductive layer which is surrounded by an etched ring in which conductive material is removed.

[0052] Figure 11Bis a plan view of a packaged radar system 1100B having one transmit antenna 1102 isolated from three receive antennas 1104A, 1104B, and 1104C using an EBG structure having a plurality of posts 1108A, 1108B, 1108C, 1108D, 1108E, and 1108F, according to one embodiment. The posts are arranged in rows, with the posts in the row forming a vertical structure or "wall" that is placed between the transmit antenna 1102 and the receive antennas. Within the row, patches of the same height of adjacent posts are capacitively coupled together laterally. Due to the EBG structure, the packaged radar system 1100B has effective isolation between the transmit antenna 1102 and one or more receive antennas 1104A, 1104B, and 1104C, and due to the compact nature of the EBG structure used, the use of the EBG structure does not significantly increase the coverage area of ​​the packaged radar system. Figure 11B In the plan view shown in FIG, each of the transmit and receive antennas is, for example, part of a fourth conductive layer surrounded by an etched ring in which the conductive material has been removed. In the plan view, the topmost patches of pillars 1108A, 1108B, 1108C, 1108D, 1108E, and 1108F are visible. The row formed by these pillars can extend between the edges of the package, or alternatively, as shown, the row can extend to etched regions 1106A and 1106B, where the conductive material in the fourth conductive layer has been removed, and etched regions 1106A and 1106B are themselves positioned on the edge of the package. The pillars can include a single unit or multiple units with patches on multiple conductive layers, thereby maximizing isolation without significantly increasing the area of ​​the corresponding EBG structure. Thus, as shown, the EBG structure is arranged between the transmit and receive antennas to isolate them. The pillars may be arranged in an array having one or more rows of pillars arranged to follow a path to form a wall that best fits the radar system layout. The array layout may follow a straight line trajectory. Alternatively, as in Figure 11B As shown in , the layout of the array can follow non-straight lines. Figure 11B A single wall is shown in FIG (ie, an array having a single row of adjacent pillars), but a double wall or triple wall of pillars may be used (ie, an array having multiple rows of pillars extending within the packaged radar may be used).

[0053] Advantageously, these walls or rows are substantially parallel to each other. Multiple walls can also be used in cases where more than one transmit antenna or transmit antenna area must be isolated from more than one receive antenna or receive antenna area. Although the square patch is Figure 11BHowever, it will be apparent to those skilled in the art that circular or other shaped patches may also be used to form the isolation walls in the EBG structure.

[0054] Figure 12A is with Figure 11A Traces 1202A, 1204A, and 1206A illustrate coupling between the transmit antenna and the first, second, and third receive antennas.

[0055] Figure 12B is with Figure 11B 12. Isolation plot associated with a packaged radar system. Traces 1202B, 1204B, and 1206B illustrate the coupling between the transmit antenna and the first, second, and third receive antennas behind a partition wall comprising a plurality of irregularly arranged pillars, according to an embodiment. Note that a 5dB to 7dB improvement in isolation between the transmit and receive antennas at the frequency of interest (60 GHz) is achieved without significantly increasing the footprint of the packaged radar system.

[0056] Figures 13 to 16 is a plan view of a packaged radar system including various isolated antenna configurations according to an embodiment.

[0057] For example, Figure 13 is a plan view of a packaged radar system 1302, which is substantially as described with respect to Figure 11B Depicted are a single transmit antenna TX, three receive antennas RX1 , RX2 , and RX3 , and a non-linear EBG structure 1304 comprising posts arranged in one or more rows.

[0058] Figure 14 is a plan view of a packaged radar system 1402 having a single transmit antenna TX, a single receive antenna RX, and a non-linear EBG structure 1404 including pillars arranged in one or more rows. Figure 15 is a plan view of a packaged radar system 1502, which is substantially as described with respect to Figure 11B Depicted are a single transmit antenna TX, three receive antennas RX1, RX2 and RX3, and an EBG structure 1504 comprising pillars arranged in one or more rows and following a trajectory having two straight sections arranged orthogonal to each other. Figure 16is a plan view of a packaged radar system 1602 having a single transmit antenna TX, a single receive antenna RX, and an EBG structure 1604 including pillars arranged in one or more rows, and the pillars follow a trajectory having two straight line portions arranged orthogonal to each other.

[0059] Although Figure 11B and Figures 13 to 16 While partition walls for various packaged radar systems are shown in the drawings, it will be recognized by those skilled in the art that various other types and shapes of partition walls and antenna configurations including multiple transmit antenna sections, receive sections, and transceiver sections can benefit from the isolation provided by the compact EBG structure described herein.

[0060] Figure 17 1700 is a flow chart of a method of forming a packaged radar system having isolated transmit and receive antennas using at least one EBG structure according to one embodiment. Methods other than those described below may also be used.

[0061] At step 1702, first and second conductive layers 818, 820 may be formed on the first layer stack 812 (such as any patches associated with the AMC cell). For example, this step may be performed using an etching process.

[0062] At step 1704 , a second layer stack 810 may be formed on the first layer stack 812 .

[0063] At step 1706 , a third conductive layer 816 may be formed on a surface of the second layer stack 810 (such as any patches associated with the AMC cell).

[0064] At step 1708 , a third layer stack 808 may be formed on the second layer stack 810 .

[0065] At step 1710 , after all three stacked layers 812 , 810 , and 808 are formed by a stacking process of dielectric materials, all rods for the EBG structure may be metallized through the three stacked layers.

[0066] At step 1712, fourth conductive layer features such as the transmit antenna 802, the receive antenna 806, and any patches associated with the AMC cell may be formed.

[0067] At step 1714 , radar transmit and receive integrated circuit 824 may be formed at any time prior to formation of the stackup layers and conductive layers of the packaged radar system.

[0068] At step 1716 , radar transmit and receive integrated circuit 824 may be attached to the bottom surface of the stack-up and conductive layers of the packaged radar system.

[0069] At step 1718 , solder ball grid features 814A and 814B may also be applied.

[0070] At step 1720 , the completed packaged radar system may be electrically tested.

[0071] At step 1722 , the packaged radar system, which may be tested, may be finally inspected and the manufacturing method is complete.

[0072] The above method can be extended to include the formation of additional layers as part of or on top of the packaged radar system (e.g., the formation of a radome), and the above method can be extended to include other processing steps, such as: forming vias and contacts within and between various conductive layers and laminate layers.

[0073] The packaged radar system described above can be used in a variety of applications, such as automotive radar, industrial radar, gesture sensors, medical applications, wall penetration detection, and motion detectors. Sensing applications include: liquid level monitoring in tanks, smart lighting control, security systems, smart door openers, and vehicle collision avoidance. Multi-channel radar systems are mainly used to replace single-channel systems when the detection of the angular position of an object is important. For example, in telecommunications applications, in applications using high frequencies such as the fifth generation (5G) mobile technology at 28 GHz, multi-channel transceivers can be used for point-to-point communications that require beamforming.

[0074] In a multi-channel implementation such as a gesture sensor system with multiple antenna elements, the size and spacing of the antenna elements are based on the desired operating frequency. For example, at 60 GHz, the distance between two antenna elements can be 3 mm to 3.5 mm.

[0075] As previously mentioned, if antenna elements are spaced closely together, multiple antenna elements may interfere with each other and with other electronic components within the RF device package. In some cases, this may limit the overall size of the RF device package. By utilizing the walls of the cell's columns to isolate the antenna elements within the RF device package, the previously described embodiments provide various advantages over conventional RF device packages.

[0076] Isolated transmitting and receiving antennas have been shown and described. In other embodiments, one or more transmitting or receiving antennas may be transceivers configured to both receive and transmit radio signals. In various embodiments, the antennas may comprise conductive materials. For example, in one embodiment, the antennas comprise copper (Cu). In some embodiments, antennas made of different conductive materials may exist in the same RF device package.

[0077] The dimensions of the aforementioned antenna can be determined by the desired response to a particular wavelength or group of wavelengths (e.g., a frequency band). In various embodiments, an antenna sensitive to millimeter wavelength radiation can have a length and width between 1 mm and 2.5 mm. In one embodiment, the length of the antenna is approximately 1.5 mm and the width of the antenna is approximately 850 μm. In an alternative embodiment, the length of the antenna is approximately 1.3 mm and the width of the antenna is approximately 1.2 mm.

[0078] The previously described integrated circuit chips may include active and passive devices, metal layers, dielectric layers, doped and intrinsic semiconductor regions, and redistribution layers, among other components known in the art. In various embodiments, the integrated circuit chips have undergone back-end-of-line (BEOL) processing before being attached to a radio frequency device package.

[0079] The integrated circuit chip may also include a radio frequency circuit. In various embodiments, the radio frequency circuit is designed to operate in a super high frequency (SHF) or extremely high frequency (EHF) regime. For example, the integrated circuit chip 10 may include a millimeter wave (MMW) circuit designed to operate in an unlicensed frequency band from 57 GHz to 64 GHz. Additionally or alternatively, the integrated circuit chip may include a circuit designed to operate in a 28 GHz regime (e.g., in 5G applications). The integrated circuit chip may have a receive interface connected to a receive antenna and / or a transmit interface connected to a transmit antenna. In some configurations, the receive interface and the transmit interface may be combined into a single interface. The integrated circuit chip may also include one or more redistribution layers (RDLs) to redistribute connections to allow one or more couplings to the first conductive layer.

[0080] For example, the aforementioned solder balls can be part of a ball grid array (BGA) for an embedded wafer level ball grid array (eWLB) package.For example, the solder balls can allow electrical coupling between circuits on the integrated circuit chip and an antenna substrate (such as a ground plane).

[0081] In various embodiments, the vertical thickness of the stack can be between 100 μm and 300 μm. In one embodiment, the vertical thickness of the stack is approximately 200 μm. In other embodiments, the vertical thickness of the stack is between 50 μm and 200 μm. In another embodiment, the vertical thickness of the stack is approximately 60 μm. The vertical thickness of the first stack can be selected to optimize the emission line characteristics in the RF device package.

[0082] In various embodiments, the RF device package may further include additional packaging material surrounding the integrated circuit chip and antenna substrate. For example, plastic, epoxy, resin, or other suitable materials may be used to encapsulate the integrated circuit chip on the bottom of the RF device package. In some embodiments, the integrated circuit chip may be encapsulated on all sides. Alternatively, one surface of the integrated circuit chip may be left exposed. The exposed surface of the integrated circuit chip may contain additional external connections.

[0083] The above method steps represent one possible method of forming a radio frequency device package, but other variations are possible. For example, the antenna and conductive shielding layer can be formed on the antenna substrate before forming the integrated circuit chip. The integrated circuit chip can also be attached at any time during the formation process. Additional steps can also be added to form other elements described in the previous embodiments. Additional steps can also include additional packaging and / or include attaching the radio frequency device package to an external support. Other variations will be apparent to those skilled in the art.

[0084] It should be noted that the designations of "top" and "bottom" with reference to features of the present invention are convenient labels and do not necessarily reflect the orientation of the features in all embodiments. For example, it is contemplated that the RF device package of the embodiments described herein is mounted with the top surface facing an external support. Thus, in some cases, the top surface may more accurately be described as the bottom surface of the device package. Similarly, the RF device package may be attached at an angle relative to an external support or housing.

[0085] Although the present invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the present invention, will be apparent to those skilled in the art upon reference to this specification. Accordingly, the appended claims are intended to cover any such modifications or embodiments.

Claims

1. A packaged radar comprising: Multiple stacked layers; a ground plane associated with at least one of the stacked layers; a transmit antenna and a receive antenna associated with at least one of the stacked layers; as well as An electromagnetic bandgap structure is arranged between the transmitting antenna and the receiving antenna, the electromagnetic bandgap structure is used to isolate the transmitting antenna from the receiving antenna, the electromagnetic bandgap structure includes a plurality of basic units, the plurality of basic units form a plurality of adjacent columns, each of the plurality of adjacent columns is coupled to the ground plane, and each of the basic units includes a conductive planar element and a columnar element coupled to the conductive planar element. The plurality of adjacent pillars of the electromagnetic bandgap structure are arranged along a non-linear path.

2. The packaged radar of claim 1 , wherein each pillar comprises a planar element at a first depth, wherein the transmit antenna and the receive antenna are at a second depth, wherein the first depth and the second depth are measured relative to a major surface of the packaged radar, and wherein the first depth is less than the second depth.

3. The packaged radar of claim 1 , wherein each of the pillars comprises: A planar element is provided at a first depth relative to a major surface of the packaged radar, and wherein the transmit antenna and the receive antenna are also located at the first depth. The packaged radar of claim 1 , wherein at least one of the pillars comprises a single base unit. The packaged radar of claim 1 , wherein at least one of the columns comprises a plurality of stacked basic units.

6. The packaged radar of claim 1 , wherein at least two of the adjacent pillars comprise: Conductive planar elements are capacitively coupled together laterally.

7. The packaged radar of claim 1, wherein at least two conductive planar elements within the column comprise different lateral dimensions.

8. The packaged radar of claim 1, wherein at least two conductive planar elements within the column comprise the same lateral dimensions.

9. The packaged radar of claim 1, wherein the plurality of adjacent pillars of the electromagnetic bandgap structure are arranged to form an array.

10. The packaged radar of claim 1 , wherein the conductive planar element comprises: Rectangular, oval, or polygonal shapes.

11. The packaged radar of claim 1 , further comprising: At least one additional layer over a top surface of the packaged radar.

12. The packaged radar of claim 1 , further comprising: A radome is provided over a top surface of the packaged radar.

13. A packaged radar comprising: Ground plane; Transmitting antenna and receiving antenna; as well as an electromagnetic bandgap structure, arranged between the transmitting antenna and the receiving antenna, and coupled to the ground plane for isolating the transmitting antenna from the receiving antenna, the electromagnetic bandgap structure comprising a plurality of adjacent pillars, each of the plurality of adjacent pillars comprising at least one conductive planar element and at least one pillar element coupled to the at least one conductive planar element, The plurality of adjacent pillars of the electromagnetic bandgap structure are arranged along a non-linear path.

14. A method of manufacturing a packaged radar, comprising: forming a plurality of stacked layers; forming a ground plane on at least one of the stacked layers; forming a transmitting antenna and a receiving antenna on at least one of the stacked layers; as well as An electromagnetic bandgap structure is arranged between the transmitting antenna and the receiving antenna, the electromagnetic bandgap structure being used to isolate the transmitting antenna from the receiving antenna, the electromagnetic bandgap structure comprising a plurality of basic units, the plurality of basic units forming a plurality of adjacent columns, each of the plurality of adjacent columns being coupled to the ground plane, and each of the basic units comprising a conductive planar element and a columnar element coupled to the conductive planar element. The plurality of adjacent pillars of the electromagnetic bandgap structure are arranged along a non-linear path.

15. The method of claim 14, wherein each pillar comprises a planar element formed at a first depth, wherein the transmit antenna and the receive antenna are formed at a second depth, wherein the first depth and the second depth are measured relative to a major surface of the packaged radar, and wherein the first depth is less than the second depth.

16. The method of claim 14, wherein each column comprises: A planar element is formed at a first depth relative to a major surface of the packaged radar, and wherein a transmit antenna and the receive antenna are also formed at the first depth.

17. The method of claim 14, wherein at least one of the pillars is formed from a single unit cell.

18. The method of claim 14, wherein at least one of the columns is formed from a plurality of stacked basic units.

19. The method of claim 14, wherein the conductive planar elements of at least two adjacent pillars are laterally capacitively coupled together.

20. The packaged radar of claim 14, wherein at least two conductive planar elements within the column are formed to have different lateral dimensions.

21. The packaged radar of claim 14, wherein at least two conductive planar elements within the column are formed to have the same lateral dimensions.

Images