Multiple Antennas on a Multilayer Board

Abstract

In one example, an apparatus includes an integrated circuit (140), a first metal layer (408), and a second metal layer (410). The first metal layer includes a first antenna (434) connected to the integrated circuit, the first antenna in a first region, the first region being external to the integrated circuit. The second metal layer includes a second antenna (444) in a second region external to the integrated circuit. The apparatus further includes a substrate (418) between the first metal layer and the second metal layer, the substrate and the first and second metal layers forming a stack. The apparatus further includes a through via (428) in the substrate coupling between the first antenna and the second antenna.

Description

[Technical field]

[0001] A portable wireless device, such as a laptop computer, a mobile phone, or a smart watch, includes multiple electronic components mounted on a substrate, such as a printed circuit board (PCB) that provides mechanical support and includes metal traces to provide electrical connections between the electronic components. The wireless device also includes an antenna that operates with a transceiver to transmit / receive radio frequency (RF) signals to facilitate wireless communication with other devices. To reduce the footprint and number of electronic components in the wireless device, the antenna may be implemented using metal traces on the PCB. Various factors may affect the performance characteristics of the antenna, such as the antenna topology, the dimensions of the antenna, the location of the antenna, and the connection between the antenna and the transceiver. Summary of the Invention

[0002] An apparatus includes an integrated circuit, a first metal layer, and a second metal layer. The first metal layer includes a first antenna connected to the integrated circuit, the first antenna in a first region, the first region being external to the integrated circuit. The second metal layer includes a second antenna in a second region external to the integrated circuit. The apparatus further includes a substrate between the first metal layer and the second metal layer, the substrate and the first and second metal layers forming a laminate. The apparatus further includes a through via in the substrate coupling between the first antenna and the second antenna. [Brief description of the drawings]

[0003] [Figure 1] 1 is a schematic diagram of an example wireless system.

[0004] [Figure 2A] 1 is a schematic diagram of another example wireless system. [Figure 2B] 1 is a schematic diagram of another example wireless system.

[0005] [Diagram 3] 2C is a graph of the frequency response of the example wireless system of FIGS. 2A and 2B.

[0006] [Figure 4A] 1 is a schematic diagram of an example wireless system having multiple antennas on multiple metal layers of a laminated substrate. [Figure 4B] 1 is a schematic diagram of an example wireless system having multiple antennas on multiple metal layers of a stacked substrate. [Figure 4C] 1 is a schematic diagram of an example wireless system having multiple antennas on multiple metal layers of a stacked substrate.

[0007] [Figure 4D] 4B is a graph of the frequency response of the example wireless system of FIG. 4A.

[0008] [Diagram 5] 2 is a schematic diagram of another example wireless system having multiple antennas on multiple metal layers of a stacked substrate;

[0009] [Figure 6A] 2 is a schematic diagram of another example wireless system having multiple antennas on multiple metal layers of a stacked substrate; [Figure 6B] 2 is a schematic diagram of another example wireless system having multiple antennas on multiple metal layers of a stacked substrate; [Figure 6C] 2 is a schematic diagram of another example wireless system having multiple antennas on multiple metal layers of a stacked substrate;

[0010] [Figure 7] 6A-6C are graphs of the frequency response of the example wireless system of FIG.

[0011] [Figure 8]1 is a schematic diagram of an example wireless system having multiple antennas on multiple metal layers of a stacked substrate. [Figure 9] 1 is a schematic diagram of an example wireless system having multiple antennas on multiple metal layers of a stacked substrate. [Figure 10] 1 is a schematic diagram of an example wireless system having multiple antennas on multiple metal layers of a stacked substrate.

[0012] [Figure 11] 11 is a graph of the frequency response of the example wireless systems of FIGS. 8-10. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 1 is a schematic diagram of an example wireless system 100, which may be part of an integrated circuit. The wireless system 100 may include a semiconductor die 102 and an impedance matching circuit 104 mounted on a substrate 106. The substrate 106 may include a metal layer 108 on a dielectric layer 110. The metal layer 108 may include a metal plane 112, a metal segment 114, and a metal segment 116, which may provide an antenna for the wireless system 100. The metal plane 112 may provide a much wider current path than the metal segments 114 and 116, and may be part of a ground plane that is coupled to a metal interconnect 120 of the semiconductor die 102. The metal segment 114 may also be a segment that is coupled between the impedance matching circuit 104 and another metal interconnect 122 of the semiconductor die 102. The semiconductor die 102 may include transceiver circuitry coupled to the metal interconnect 122 for transmitting / receiving RF signals via an antenna, and the metal segment 114 may be a feed line for the antenna.

[0014] The impedance matching circuit 104 may include an alternating current (AC) capacitor having a first plate coupled to the metal segment 114 and a second plate coupled to the metal segment 116. The impedance of the AC capacitor may be combined with the impedance of the metal segment 116 / antenna. The combined impedance may be adjusted by selecting / configuring the capacitance of the AC capacitor to match the impedance of the metal segment 114. Matching the impedance may improve power transfer between the transceiver circuitry and the antenna, improving the overall sensitivity and efficiency of the wireless system. For example, the metal segment 116 may have a capacitance of R L + j X L where R L and X L represent the respective resistive and reactive components of the impedance of the metal segment 116. The transceiver circuit also S + j X S where R S and X S represent the respective resistive and reactive components of the impedance of the transceiver circuit. To maximize (or at least increase) the power transfer between the transceiver circuit and the antenna, the impedance matching circuit 104 matches the impedance of the metal segment 116 to R S-j X S The impedance of the transceiver circuit can be converted to the complex conjugate of the impedance of the transceiver circuit,

[0015] To improve the radiation resistance, bandwidth, and efficiency of the antenna, the electrical path provided by the metal segment 116 can be extended. To reduce the footprint of the electrical path, the metal segment 116 can include multiple sub-segments (e.g., 116a, 116b, 116c, and 116d) joined together, with adjacent sub-segments (e.g., 116a and 116b, 116b and 116c) angled (e.g., 90 degrees) from each other to form a serpentine metal segment, and the antenna can be a serpentine antenna. The first end 130 of the metal segment 116 can be coupled to the impedance matching circuit 104, and the second end 132 of the metal segment 116 can be an open / unconnected end. In some examples, the second end 132 of the metal segment 116 can be coupled to the metal plane 112, and the metal segment 116 can form a loop antenna.

[0016] The semiconductor die 102, the impedance matching circuit 104, and the metal layer 108 may also be encapsulated in an encapsulating package 140. The encapsulating package 140 may be made of a molding compound (e.g., plastic or resin) to provide electrical insulation between the metal plane 112 and the metal segments 114 and 116, and between the metal interconnects of the semiconductor die 102. The surfaces of the encapsulating package 140, including surfaces 142 and 144 (parallel to the xz plane), surfaces 146 and 148 (parallel to the zy plane), and surface 150 (parallel to the xy plane), may also be coated with a layer of metal. The coating may be performed by a full surface metal sputtering process. The metal layer may shield the semiconductor die 102 and the impedance matching circuit 104 from unwanted RF signals, such as radiation or other out-of-band RF signals.

[0017] Although the metal layers on the surfaces 142-150 can shield the electronic components in the encapsulated package 140 from radiating or other undesired RF signals, these metal layers can also shield the metal segment 116, preventing it from receiving or transmitting RF signals from the encapsulated package 140. One way to reduce the shielding effect of the metal layer on the antenna is by covering only a portion of the surfaces 142-150 with the metal layer. For example, in FIG. 1, the surface 146 and a portion of the surfaces 142, 144, 150 adjacent to the metal portion 116 can be left uncovered to provide an opening through which the antenna can receive or transmit RF signals from the encapsulated package 140. A partial surface metal sputtering process can also be performed to cover a portion of the surfaces 142-150 with the metal layer. However, such an arrangement can also allow undesired RF signals to enter through the encapsulated package 140, reducing the shielding effect. Also, the limited precision of the partial surface metal sputtering process may result in variations in the dimensions and location of the aperture, which may increase performance uncertainty of the antenna and the entire wireless system 100.

[0018] 2A and 2B are schematic diagrams of another example wireless system 200. FIG. 2A illustrates a top view and FIG. 2B illustrates a perspective view. The wireless system 200 may include a semiconductor die 102 and an impedance matching circuit 104 mounted on a substrate 206, and the semiconductor die 102 and the impedance matching circuit 104 may be encapsulated in an encapsulating package 140. With reference to FIG. 2A and 2B, the substrate 206 may include multiple metal layers, such as metal layers 208, 210, 212, and 214, and multiple dielectric layers, such as dielectric layers 218, 220, 222, and 224, that form the stacked substrate 206. The substrate 206 may also include through vias 226 and 228 that penetrate the multiple metal and dielectric layers to provide electrical connections between the multiple metal layers. In some examples, the substrate 206 may include a multi-layer printed circuit board (PCB), the metal layers may include copper layers, and the dielectric layers may include epoxy materials. In some examples, the substrate 206 may also include multiple PCBs stacked together. For example, the metal layer 208 and the dielectric layer 218 may be a first PCB, the metal layer 210 and the dielectric layer 220 may be a second PCB, the metal layer 212 and the dielectric layer 222 may be a third PCB, and the metal layer 214 and the dielectric layer 224 may be a fourth PCB.

[0019] The metal layer 208 may also include a metal plane 230, which may include planar regions 230a and 230b and a separation area 230c exposing the dielectric layer 218 between the planar regions 230a and 230b. The separation area 230c may be filled with an insulating material, such as a dielectric and air. The metal layer 208 may also include metal segments 232, 234, and 236. The metal segment 232 may include subsegments 232a and 232b. The subsegment 232a may extend from a first portion of the planar region 230a that is not covered by the encapsulation package 140 (labeled "A" in FIG. 2A). The subsegment 232b extends from and is angled relative to the subsegment 232a. The sub-segment 232b may extend into a second portion (labeled "B" in FIG. 2A) of the planar region 230a and couple to the impedance matching circuit 104. The sub-segment 232b may be spaced from the planar region 230b by a separation area 230c. The planar region 230a and the metal segment 232 may provide a loop antenna 240 that may conduct a current around a loop in response to detection of an RF signal or to transmit / radiate an RF signal, and a portion of the metal sub-segment 232b may provide a feed line for the loop antenna. The loop antenna 240 may be in an external region adjacent to the encapsulation package 140. Thus, the loop antenna 240 is less obstructed by the encapsulation package 140, allowing the loop antenna 240 to transmit and receive RF signals.

[0020] The metal segment 234 may also include a serpentine segment, which has a first end 250 that is unconnected / separated from the planar region 230a, forming an unconnected / open end. The serpentine segment also has a second end 252 that connects with the sub-segment 232b. The serpentine metal segment 234 may provide an inductive load, which may be adjusted by varying the length of the metal segment 234 and the spacing between the serpentine sub-segments (labeled "d" in FIG. 2A). Also, to provide a capacitive load, there may be a gap 230d between the sub-segment 232b and the planar region 230b, which may be adjusted by varying the width of the gap 230d (labeled "w" in FIG. 2A). The gap 230d may be filled with an insulating material, such as a dielectric and air. The inductive and capacitive loads in combination with the impedance matching circuit 104 may be configured to adjust the impedance of the feed line of the loop antenna 240 to match the impedance of the semiconductor die 102 (represented by the impedance of the metal segments 236 and the metal interconnects 122). Impedance matching can improve power transfer between the transceiver circuitry and the antenna, and can improve the overall sensitivity and efficiency of the antenna.

[0021] Although the loop antenna 240 in the wireless system 200 of FIG. 2 can receive or transmit RF signals unimpeded (or less impeded) by the encapsulated package 140, various factors may limit its performance. Specifically, the resonance of the loop antenna 240 is narrowband, and the loop antenna 240 may have a narrow bandwidth for transmitting / detecting RF signals. For example, the loop antenna 240 may have a bandwidth of 5-10 megahertz (MHz). The narrow bandwidth may be inappropriate for many wireless applications in which the antenna may transmit / receive RF signals over a bandwidth wider than 5-10 MHz.

[0022] Also, because loop antenna 240 is in an external area adjacent encapsulation package 140 and adds to the footprint of wireless system 200, the loop dimensions of loop antenna 240 may be reduced (e.g., by reducing the length of sub-segments 232a and 232b) to reduce the overall footprint of wireless system 200. However, reducing the loop dimensions may reduce the radiation efficiency and gain of loop antenna 240. This may reduce the power of the RF signals transmitted or received by loop antenna 240 and reduce the transmission / detection range of the antenna. The overall sensitivity and efficiency of wireless system 200 may be further reduced due to the increased inductance of the antenna loop, which makes it difficult to match the impedance between the antenna loop and semiconductor die 102.

[0023] 3 is a graph 300 of the variation of return loss (RL) of the loop antenna 240 of FIGS. 2A and 2B with respect to frequency. In FIG. 3 and for the remainder of the present invention, return loss is the amount of power reflected / rejected by the loop antenna 240 (P r ) and the amount of power provided to the loop antenna 240 (P i ) when the loop antenna 240 transmits an RF signal, P i may refer to the amount of power provided to the loop antenna 240 by the semiconductor die 102. When the loop antenna 240 detects an RF signal, P i may refer to the amount of power detected by the loop antenna 240. RL may be given by the following equation: RL=10log 10 (P r / P i ) (Formula 1)

[0024] Referring to FIG. 3, the loop antenna 240 provides a resonant system and can reject RF signals in frequency bands between 1 and 2 gigahertz (GHz) and between 2.7 and 5 GHz with a return loss close to unity. The loop antenna 240 can transmit / receive RF signals in a frequency band between 2 and 2.7 GHz. The bandwidth of the loop antenna 240 can include a frequency band where the return loss is less than -10 dB, which is labeled "BW0" in FIG. 3 and is approximately 75 MHz. The resonant frequency of the loop antenna 240 is 2.4 GHz, where the return loss is approximately 1.5 dB, which is labeled "RL0" in FIG. 3. min0 " is the minimum value of -15 dB. The narrow 75 MHz bandwidth of the loop antenna may be inadequate for many wireless applications.

[0025] 4A-4D illustrate an example wireless system 400 that can address at least some of the problems discussed above. FIG. 4A is a schematic diagram illustrating an exploded perspective view of the wireless system 400, and FIG. 4B is a schematic diagram illustrating a partial side view of the wireless system 400. With reference to FIGS. 4A and 4B, the wireless system 400 may include a semiconductor die 102 and an impedance matching circuit 104 mounted on a substrate 406, with at least the semiconductor die 102 encapsulated in an encapsulating package 140. The substrate 406 may include multiple metal layers, such as metal layers 408, 410, and 412, and multiple dielectric layers, such as dielectric layers 418, 420, and 422, stacked together to form a stacked substrate. The substrate 406 may also include through vias 426 and 428 that extend through the multiple metal layers and the dielectric layers to provide electrical connections between the multiple metal layers. In some examples, the substrate 406 may include a multi-layer PCB, the metal layer may include a copper layer, and the dielectric layer may include an epoxy material. In some examples, the substrate 406 may include multiple PCBs stacked together, where the metal layer 408 and the dielectric layer 418 may be of a first PCB, the metal layer 410 and the dielectric layer 420 may be of a second PCB, and the metal layer 412 and the dielectric layer 422 may be of a third PCB, and these PCBs may be stacked to form the stacked substrate 406.

[0026] Each metal layer may include a metal plane and a metal segment, which extends from a first portion of the metal plane and returns to a second portion of the same metal plane to form a loop antenna. Specifically, the metal layer 408 may include a metal plane 430, which includes planar regions 430a and 430b and an isolation region 430c exposing the dielectric layer 418 between the planar regions 430a and 430b. The isolation region 430c may be filled with an insulating material, such as a dielectric and air. The metal plane 430 may be coupled to a voltage source and may be configured as a ground plane. The metal layer 408 may also include a metal segment 432, which includes metal subsegments 432a and 432b. The metal subsegment 432a may extend from a portion (labeled "A" in the figure) of the planar region 430b. The metal sub-segment 432b may extend from an end 433 of the metal sub-segment 432a and may be angled relative to the metal sub-segment 432a, with the metal sub-segment 432b being coupled to the impedance matching circuit 104 at an end 435. The through via 428 extends through the metal sub-segment 432b and is closer to the end 435 than the metal sub-segment 432a. A loop antenna 434 may be provided in which the metal segments 432, 435 are spaced from the encapsulated package 140 by a separation area 430c. The loop antenna 434 may conduct current through the edge of the planar region 430a and through the metal segment 432 to reach the impedance matching circuit 104 in response to detecting an RF signal or to transmit an RF signal. The metal layer 408 may also include a metal segment 436 that couples between the impedance matching circuit 104 and the semiconductor die 102 to conduct current therebetween. The metal sub-segment 432b may also be spaced apart from the planar region 430b by a gap 430d. The gap 430d may be filled with an insulating material, such as a dielectric and air, and may provide a capacitive load that, in combination with the AC capacitance of the impedance matching circuit 104, may be set to match the impedance of the loop antenna 434 with the metal segment 436. The capacitive load may be set by the width of the gap 430d (labeled "w" in FIG. 4A).

[0027] The metal layer 410 may also include a metal plane 440, which includes planar regions 440a and 440b and an isolation area 440c exposing the dielectric layer 420 between the planar regions 440a and 440b. The isolation area 440c may be filled with an insulating material, such as a dielectric and air. The metal plane 440 may be coupled to the metal plane 430 by a through via 426 and may be configured as a ground plane. The metal layer 410 may also include a metal segment 442, which includes metal subsegments 442a and 442b. The metal subsegment 442a may extend from a portion of the planar region 440a (labeled "B" in FIG. 4A). Metal subsegment 442b may extend from end 443 of metal subsegment 442a and may be angled relative to metal subsegment 442a, with metal subsegment 442b having an end 445 that is spaced / separated from metal plane 440 to form an open / unconnected end. Through via 428 extends through metal subsegment 442b to provide an electrical connection between metal segments 432 and 442 and is closer to end 445 than metal subsegment 442a. Metal segments 442, 445, along with through via 428 between metal layers 408 and 410, may provide a loop antenna 444 that is spaced from encapsulated package 140 by separation area 440c. The loop antenna 444 can conduct current through the edges of the planar region 440a, through the metal segment 442, and through the through via 428 between the metal layers 408 and 410 to reach the impedance matching circuit 104 and the semiconductor die 102 in response to detecting an RF signal or to transmit an RF signal. The metal sub-segment 442b can also be separated from the planar region 440b by a gap 440d. The gap 440d can be filled with an insulating material, such as a dielectric and air, and can provide a capacitive load that can be set to match the impedance of the loop antenna 444 with the metal segment 436. The capacitive load can be set by the width of the gap 440d (labeled "w" in FIG. 4A).

[0028] Also, the metal layer 412 may include a metal plane 450 including planar regions 450a and 450b, and an isolation area 450c exposing the dielectric layer 422 between the planar regions 450a and 450b. The isolation area 450c may be filled with an insulating material such as a dielectric and air. The metal plane 450 may be coupled to the metal planes 430 and 440 by through vias 426 and may be configured as a ground plane. The metal layer 412 may also include a metal segment 452 including metal subsegments 452a and 452b. The metal subsegment 452a may extend from a portion of the planar region 450a (labeled "C" in FIG. 4A). The metal subsegment 452b may extend from an end 453 of the metal subsegment 452a and may be angled relative to the metal subsegment 452a, and the metal subsegment 452b may have an end 455 that is away / separated from the metal plane 450 to form an open / unconnected end. The through via 428 extends through the metal sub-segment 452b to provide an electrical connection between the metal segment 452 and the metal segments 432 and 442, and is closer to the end 455 than the metal sub-segment 452a. The metal segment 452, together with the through via 428 between the metal layers 408 and 412, can provide a loop antenna 454. The loop antenna 454 can conduct current through the edge of the planar region 450a, through the metal segment 452, and through the through via 428 between the metal layers 408 and 412 to reach the impedance matching circuit 104 and the semiconductor die 102 in response to detecting an RF signal or transmitting an RF signal. The metal sub-segment 452b can be separated from the planar region 450b by a gap 450d that is part of the separation area 450c. The gap 450d can be filled with an insulating material, such as a dielectric and air, to provide a capacitive load that can be set to match the impedance of the loop antenna 454 to the metal segment 436. The capacitive load can be set by the width of the gap 450d (labeled "w" in FIG. 4A).

[0029] In the exemplary arrangement of Figures 4A-4C, the three loop antennas 434, 444, and 454 may be coupled to the impedance matching circuit 104 and the semiconductor die 102 by through vias 428. The connections between the loop antennas 434, 444, and 454, the impedance matching circuit 104, and the semiconductor die 102 are depicted in the circuit diagram of Figure 4C. Referring to Figure 4C, a metal segment 436 is coupled between a transceiver circuit 460 of the semiconductor die 102 and one side of a capacitor of the impedance matching circuit 104. And, the other side of the capacitor of the impedance matching circuit 104 is coupled to the three loop antennas 434, 444, and 454 by through vias 428, which may provide a feed line for each of the three antennas. Thus, the transceiver circuit 460 may use one or more of the three loop antennas 434, 444, and 454 to transmit and receive RF signals.

[0030] Multiple loop antennas 434, 444, and 454 can have similar frequency responses that can be combined to extend the operating frequency range of the wireless system 400. The radiation efficiency and gain of the combined antennas can also be increased across the frequency range.

[0031] 4D illustrates a chart 470 including graphs 472, 474, and 476 of the return loss of each of the loop antennas 434, 444, and 454, and a chart 480 of the combined return loss of the three loop antennas. Referring to the chart 470, the loop antenna 434 can have a resonant frequency at f0 with a minimum return loss, the loop antenna 444 can have a resonant frequency at f1 with a minimum return loss, and the loop antenna 454 can have a resonant frequency at f2 with a minimum return loss within the range of frequencies depicted in FIG. 4D. The loop antennas can have different resonant frequencies because they have different loop dimensions. As mentioned above, the loop antenna 444 can include a through via 428 between the metal layers 408 and 410, which extends the current path and increases the loop dimension of the loop antenna 444. The loop antenna 454 may also include through vias 428 between the metal layers 408 and 412, which also extend the current path and increase the loop dimension of the loop antenna 454. Because each loop antenna has a different current path extension from the through vias 428, it can have different loop dimensions and different resonant frequencies.

[0032] Also, each loop antenna may have the same bandwidth (e.g., BW0) centered around the respective resonant frequencies f0, f1, and f2. Although the resonant frequencies f0, f1, and f2 are different, there is a frequency range f0 that includes the resonant frequencies f0, f1, and f2. a and f b The difference is small so that the frequency responses of the loop antennas can be combined over the frequency range f. Chart 480 represents the combined return loss of loop antennas 434, 444, and 454. Referring to chart 480, a From f b The combined bandwidth (labeled “BW1”) of antennas 434, 444, and 454 spanning between them can be wider than the bandwidth BW0 of each standalone antenna, thereby increasing the overall bandwidth of wireless system 400 when transmitting / detecting RF signals.

[0033] In the example of Figures 4A-4D, the metal segment 432 of the metal layer 408, the metal segment 442 of the metal layer 410, and the metal segment 452 of the metal layer 412 may be on the same side of the encapsulating package 140, and the loop antennas 434, 444, and 454 may form a stack (e.g., along the z-axis). In some examples, the antennas in different metal layers may be on different sides of the encapsulating package 140. Figure 5 is a schematic diagram of an example wireless system 400 having loop antennas 434 and 444 on different sides of the encapsulating package 140. With reference to Figure 5, the planar regions 430a and 430b, the separation area 430c, the gap 430d, and the metal sub-segments 432a and 432b may be on a first side (e.g., direction C) of the encapsulating package 140. Also, planar regions 440a and 440b, separation area 440c, gap 440d, and metal sub-segments 442a and 442b may be on a second side (e.g., direction D) of encapsulated package 140. A different metal layer (e.g., metal layer 412) may include metal segment 502 coupling between metal sub-segment 442b and through via 428, and metal segment 502 may be coupled to metal sub-segment 442b by through via 504.

[0034] 6A-6C illustrate another exemplary wireless system 400. FIG. 6A is a schematic diagram illustrating an exploded perspective view of the wireless system 400, and FIG. 6B is a schematic diagram illustrating a partial side view of the wireless system 400. Referring to FIGS. 6A and 6B, the metal segment 442 includes a metal subsegment 602 extending from an end 445 of the metal subsegment 442b that is closer to the through via 428 than the metal subsegment 442a. The metal subsegment extension 602 has an open end 604 separated from the metal plane 440. Also, the metal segment 452 includes a metal subsegment extension 612 extending from an end 455 of the metal subsegment 442b that is closer to the through via 428 than the metal subsegment 452a. The metal subsegment extension 612 has an open end 614 separated from the metal plane 450. In the example of Figures 6A and 6B, ends 445 and 455 may be imaginary ends for illustration purposes, where metal subsegments 442b and 602 may be continuous metal subsegments, and metal subsegments 452b and 612 may be continuous metal subsegments.

[0035] Each of the metal sub-segment extensions 602 and 612 may be an open stub that can provide additional capacitive loading to the respective metal segments 442 and 452 and the respective loop antennas 444 and 454. FIG. 6C is a circuit schematic diagram illustrating the capacitive loading provided by the loop antennas 434, 444, and 454, the impedance matching circuit 104, the semiconductor die 102, and the metal sub-segment extensions 602 and 612. Referring to FIG. 6C, the metal segment 436 is coupled between the transceiver circuit 460 of the semiconductor die 102 and one side of the capacitor of the impedance matching circuit 104. And, the other end of the capacitor of the impedance matching circuit 104 is connected to the three loop antennas 434, 444, 454 by the through vias 428 as feed lines. Additionally, metal subsegment extension 602 can provide a shunt capacitive load between through via 428 and antenna 444, and metal subsegment extension 612 can provide a shunt capacitive load between through via 428 and antenna 454.

[0036] The shunt capacitive load can be configured to adjust the impedance of the respective loop antennas 444 and 454. For example, the capacitance C ext can provide a reactive component that can be combined with the reactive component of the loop antenna 444 / 454 impedance to provide capacitive tuning. For example, the capacitance C ext can be adjusted so that the combined impedance of the loop antenna 444 / 454 and the respective metallic sub-segment extension 602 / 612 can be equal to the complex conjugate of the impedance of the transmitter circuitry to maximize power transfer.

[0037] Metal sub-segment extensions 602 and 612, together with impedance matching circuit 104, can provide different options for tuning the combined impedance of the loop antenna to further improve the impedance match between the feed line and metal segment 436 (and transceiver circuitry 460) and to improve power transfer between the transceiver circuitry and the antenna. For example, C ext can be set by the length (along the y-axis) and width (along the x-axis) of the metal sub-segment extension. Also, in some examples, different loop antennas can have metal sub-segment extensions of different lengths / widths to provide different capacitive loads. This is because different loop antennas can have different loop dimensions and therefore different C shunt Therefore, the metal sub-segment extensions 602 and 612 may have different capacitances and capacitive reactances to combine with the different capacitive reactances of the respective loop antennas 444 and 454 to adjust the combined impedance of the loop antennas. ext It can have different dimensions to provide capacitance.

[0038] 7 is a graph 700 of the variation of combined return loss (RL) versus frequency for the loop antennas 434, 444, and 454 of FIGS. 6A-6C. In FIG. 7, the combined bandwidth of the loop antenna 240 can include a frequency range where the return loss is below −10 dB, which is referred to as the “BW i " and is about 105 MHz. Compared to Figure 3, the bandwidth is 40% wider. Also, the combined resonant frequency of the loop antenna is 2.4 GHz, which is the same as Figure 3. However, in Figure 7, "RL min1The return loss at the resonant frequency labeled " is -30 dB, which represents a 15 dB improvement from FIG. 3. The reduced return loss can be due to, for example, improved impedance matching between the feed line (and the combined impedance of the loop antenna) and the metal segment 436 (and the transceiver circuitry 160) provided by metal sub-segment extensions 602 and 612, isolation areas 430c, 440c, and 450c, and impedance matching circuitry 104.

[0039] 8, 9, and 10 are schematic diagrams of an example wireless system including a multi-band antenna in a multi-layer substrate. Each of FIGS. 8, 9, and 10 is a schematic diagram illustrating a perspective view and an exploded view of an example wireless system 800. With reference to FIGS. 8-10, the wireless system 800 may include a semiconductor die 102 (not shown in FIGS. 8-10) and an impedance matching circuit 104 mounted on a substrate 806, where at least the semiconductor die 102 is encapsulated in an encapsulating package 140. The substrate 806 may include multiple metal layers, such as metal layers 808 and 810. The substrate 806 may also include dielectric layers 818 and 820. The metal layers and dielectric layers may be stacked together to form a stacked substrate. In some examples, the substrate 806 may also include other metal layers and dielectric layers (not shown in FIG. 8) between the metal layers 408 and 810. The substrate 806 may also include through vias 826 and 828 that penetrate the multiple metal and dielectric layers to provide electrical connections between the multiple metal layers. In some examples, the substrate 806 may include a multi-layer PCB, where the metal layers may include copper layers and the dielectric layers may include epoxy materials. In some examples, the substrate 806 may include multiple PCBs laminated together, where the metal layer 408 and the dielectric layer 418 may be of a first PCB, and the metal layer 810 and the dielectric layer 820 may be of a second PCB, and the PCBs may be stacked to form the laminated substrate 806.

[0040] Each metal layer may include a metal plane and a metal segment, which may be configured as an antenna. The wireless system 800 may include antennas with different topologies and different operating frequency bands in different metal layers. For example, referring to FIG. 8, the metal layer 808 may include a metal plane 830, which may include planar regions 830a and 830b and an isolation area 830c exposing the dielectric layer 818 between the planar regions 830a and 830b. The isolation area 830c may be filled with an insulating material such as a dielectric and air. The metal plane 830 may be coupled to a voltage source and may be configured as a ground plane. The metal layer 808 may also include a metal segment 832, which may include a metal sub-segment 832a extending from a portion of the planar region 830a (labeled "A" in FIG. 8). Metal subsegment 832b may extend from metal subsegment 832a and may be angled relative to metal subsegment 832a, with metal subsegment 832b having an end 833 that is coupled to impedance matching circuit 104. A through via 828 extends through metal subsegment 832b and is closer to end 833 than metal subsegment 832a. Metal segment 832 may provide a loop antenna 834 that is spaced from encapsulated package 140 by isolation area 830c and spaced from planar region 830b by gap 830d. ​​Gap 830d may be filled with an insulating material, such as a dielectric and air. Metal layer 808 may also include metal segment 836 that is coupled between impedance matching circuit 104 and semiconductor die 102.

[0041] 8, the metal layer 810 may include a metal plane 840a and an isolation area 840b. The isolation area 840b may be in an exterior area adjacent to the encapsulated package 140. The isolation area 840b may be filled with an insulating material, such as a dielectric and air. The metal plane 840a may be coupled to the metal plane 830 by a through via 826 and may be configured as a ground plane. The metal layer 810 may also include a metal segment 842 that is spaced from the encapsulated package 140 and the plane area 840a by the isolation area 840b, with opposing ends 844 and 846 of the metal segment 842 being separated / separate from the metal plane 840a. The end 846 may be an open end. The through via 828 extends through the metal segments 832 and 842 and is closer to the end 844 than the end 846. Metal segment 842 may include multiple sub-segments connected together, with adjacent sub-segments (e.g., 842a and 842b, 842b and 842c) angled (e.g., 90 degrees) from one another. Metal segment 842 may form a serpentine antenna 854 with through vias 828 between metal layers 808 and 810. Serpentine antenna 854 may conduct current through metal segment 842 and through through vias 428 between metal layers 808 and 810 to reach impedance matching circuit 104 and semiconductor die 102 in response to detecting an RF signal or transmitting an RF signal. In some examples, metal layer 810 may include metal sub-segment extensions (not shown in FIGS. 8-10 ) extending from end 844 to provide additional capacitive loading for capacitive tuning of the impedance of antenna 854, as described above in FIGS. 6A-6C .

[0042] 9 and 10 illustrate additional examples of the wireless system 800. In FIG. 9, the metal layer 810 may include a metal segment 902 in the isolated area 840b, which may be in an external region proximate the encapsulation package 140. The metal segment 902 may include a metal sub-segment 902a and a metal sub-segment 902b. The metal sub-segment 902a may extend from a first portion of the planar region 840a (e.g., labeled "B" in FIG. 9) and may have an end 904 that is separated / separate from a second portion of the planar region 840a (labeled "C" in FIG. 9). The end 904 may be an open / unconnected end. Also, metal subsegment 902b may extend from metal subsegment 902a and be angled relative to metal subsegment 902a, and metal subsegment 902b may have an end 916 that is away / separated from metal plane 840a to form an open / unconnected end. Metal subsegment 902b may be closer to ground plane 840a than end 904. Through via 828 extends through metal subsegment 902b to provide an electrical connection between metal segments 832 and 902 and is closer to end 916 than metal subsegment 902a. Metal segment 902, along with through via 828 between metal layers 808 and 810, may form an inverted-F antenna 920. Also, in FIG. 10, wireless system 800 may include metal layer 808 including metal segment 842 providing serpentine antenna 854 and metal layer 810 including metal segment 902 providing inverted-F antenna 920. 9 and 10, metal layer 810 may include a metal sub-segment extension (not shown in FIG. 10) extending from end 916 of metal sub-segment 902b to provide additional capacitive loading for capacitive tuning of the impedance of antenna 920.

[0043] In some examples, the metal layer 808 may also include a metal segment 902 to provide an inverted-F antenna 920, where the impedance matching circuit 104 may be coupled to an end 916 of the metal sub-segment 902b, and the metal layer 810 may include a metal segment 842 to provide a serpentine antenna 854.

[0044] FIG. 11 is a graph 1100 of the variation of the combined return loss (RL) of the multi-band antennas of FIGS. 8-10. Referring to FIG. 11, the multi-band antenna may have two non-overlapping operating frequency ranges. The first operating frequency range may be centered around 1.9 GHz and have a bandwidth labeled BW3, and the second operating frequency range may be centered around 4.1 GHz and have a bandwidth labeled BW4, where a first antenna of the multi-band antenna may have a first resonant frequency of 1.9 GHz and a second antenna of the multi-band antenna may have a second resonant frequency of 4.1 GHz. The return loss at the first resonant frequency of 1.9 GHz is −18 dB ("RL min3 ") and the return loss at the second resonant frequency of 4.1 GHz may be -14 dB (labeled "RL min4 ").

[0045] The techniques described above may be used to implement a variety of antenna types, including omnidirectional and directional antennas, in a multi-layer substrate. Examples of omnidirectional antennas may include loop and serpentine antennas, such as loop antenna 834 and serpentine antenna 854 in Figures 8-10. Examples of directional antennas may include patch antennas, Vivaldi antennas, multi-layer helical antennas, and horn antennas.

[0046] The term "coupled" in this description may encompass a connection, communication, or signal path that enables a functional relationship consistent with this description. For example, if device A provides a signal to control device B to perform an action, (A) in a first example, device A is directly electrically coupled to device B, or (b) in a second example, device A is indirectly electrically coupled to device B via an intervening component C, where the intervening component C does not substantially change the functional relationship between device A and device B, such that device B is controlled by device A via a control signal provided by device A.

[0047] In this description, a device that is "configured to" perform a certain task or function may be configured (e.g., programmed and / or hardwired) at the time of manufacture by a manufacturer to perform that function and / or may be configurable (or reconfigurable) by a user after manufacture to perform that function and / or other additional or alternative functions. Such configuration may be through the device's firmware and / or software programming, through the construction and / or layout of the device's hardware components and interconnections, or a combination thereof.

[0048] A circuit or device described herein as including certain components may instead be adapted to be electrically coupled to those components to form the described circuit element or device. For example, a structure described herein as including one or more semiconductor elements (such as transistors), one or more passive elements (such as resistors, capacitors, and / or inductors), and / or one or more sources (such as voltage and / or current sources) may instead include only semiconductor elements in a single physical device (e.g., a semiconductor die and / or integrated circuit (IC) package) and may be adapted to be electrically coupled to at least some of the passive elements and / or sources, either during or after manufacture, such as by an end user and / or a third party, to form the described structure.

[0049] Although certain components may be described herein as being of a particular process technology, these components may be swapped for components of other process technologies. Circuits described herein are reconfigurable to include replaced components to provide functionality at least partially similar to that available prior to the component replacement. A component shown as a resistor generally represents any one or more elements coupled in series and / or parallel to provide the amount of impedance represented by the resistor shown, unless otherwise noted. For example, a resistor or capacitor shown and described herein as a single component may instead be multiple resistors or capacitors, respectively, coupled in series or parallel between the same two nodes as the single resistor or capacitor.

[0050] Use of the phrase "ground voltage potential" in this description includes chassis ground, earth ground, floating ground, virtual ground, digital ground, common ground, and / or any other form of ground connection applicable or suitable to the teachings of this description. Unless otherwise specified, in this description, "about," "approximately," or "substantially" preceding a parameter means within + / - 10% of that parameter.

[0051] Modifications may be made to the exemplary embodiments described, and other embodiments are possible, within the scope of the invention.

Claims

1. 1. An apparatus comprising: an integrated circuit; a first metal layer including a first ground plane and a first antenna, the first antenna being coupled to the integrated circuit and located in a first region external to the integrated circuit, the first antenna including a first portion and a second portion; a second metal layer including a second ground plane and a second antenna, the second antenna being in a second region external to the integrated circuit, the second antenna including a third portion overlapping the first portion and a fourth portion overlapping the second portion, the second antenna having a different frequency response than the first antenna; and a substrate between the first and second metal layers; a through via in the substrate, the through via coupled between a first portion of the first antenna and a third portion of the second antenna; Including, the integrated circuit at least partially overlaps the first ground plane; The substrate, the first metal layer, and the second metal layer form a stack.

2. 10. The apparatus of claim 1, the first metal layer further includes a first metal segment spaced from the integrated circuit by a first area, the first metal segment forming the first antenna; the second metal layer includes a second metal segment spaced from the integrated circuit by a second area, the second metal segment forming the second antenna; The device, wherein the through via extends through the first and second metal segments.

3. 3. The apparatus of claim 2, the first metal segment includes a first metal sub-segment and a second metal sub-segment, the first metal sub-segment extending from the first ground plane, the second metal sub-segment extending from an end of the first metal sub-segment and angled relative to the first metal sub-segment, the second metal sub-segment having an end remote from the first ground plane; the through via extends through the second metal sub-segment and is closer to the end of the second metal sub-segment than to the end of the first metal sub-segment.

4. 4. The apparatus of claim 3, the second metal segment includes a third metal sub-segment and a fourth metal sub-segment, the third metal sub-segment extending from the second ground plane, the fourth metal sub-segment extending from an end of the third metal sub-segment and angled relative to the third metal sub-segment, the fourth metal sub-segment having an end remote from the second ground plane; the through via extends through the fourth metal sub-segment and is closer to the end of the fourth metal sub-segment than to the end of the third metal sub-segment.

5. 5. The apparatus of claim 4, the second metal segment further includes a fifth metal subsegment extending from an end of the fourth metal subsegment that is closer to the through via than the third metal subsegment, the fifth metal subsegment having an end that is away from the second ground plane.

6. 6. The apparatus of claim 5, the integrated circuit includes a transceiver circuit coupled to the first metal segment; The apparatus, wherein the length of the fifth metal sub-segment is based on an impedance of the transceiver circuit.

7. 5. The apparatus of claim 4, the first and second metal sub-segments form a second portion of the first antenna as a first loop antenna, and the third and fourth metal sub-segments form a fourth portion of the second antenna as a second loop antenna.

8. 8. The apparatus of claim 7, 1. An apparatus, wherein the first loop antenna is configured to have a first resonant frequency and a first bandwidth, and the second loop antenna is configured to have a second resonant frequency and a second bandwidth, such that the first loop antenna and the second loop antenna have a combined bandwidth that is wider than each of the first bandwidth and the second bandwidth.

9. 9. The apparatus of claim 8, The apparatus, wherein the first loop antenna and the second loop antenna have different loop dimensions.

10. 9. The apparatus of claim 8, The device, wherein the first metal segment and the second metal segment have different widths.

11. 3. The apparatus of claim 2, the first metal segment having opposing first and second ends, the first and second ends spaced apart from the first ground plane.

12. 12. The apparatus of claim 11, The apparatus, wherein the first metal segment forms a second portion of the first antenna and comprises a serpentine metal segment.

13. 3. The apparatus of claim 2, the first metal segment includes a first metal sub-segment and a second metal sub-segment, the first metal sub-segment extending from the first ground plane and having an end remote from the first ground plane, the second metal sub-segment extending from the end of the first metal sub-segment and angled relative to the first metal sub-segment, the second metal sub-segment being closer to the first ground plane than the end of the first metal sub-segment; the through via extends through the second metal sub-segment and is closer to an end of the second metal sub-segment than to an end of the first metal sub-segment; Device.

14. 14. The apparatus of claim 13, The apparatus, wherein the first metal segment is part of an inverted-F antenna.

15. 3. The apparatus of claim 2, The apparatus further includes an impedance matching circuit coupled between the integrated circuit and the first metal segment.

16. 16. The apparatus of claim 15, The apparatus, wherein the impedance matching circuit includes a capacitor coupled between the integrated circuit and the first metal segment.

17. 10. The apparatus of claim 1, The apparatus, wherein the integrated circuit includes a package covered with a metal layer.

18. 10. The apparatus of claim 1, The apparatus, wherein the substrate is part of a printed circuit board (PCB).

19. 10. The apparatus of claim 1, The apparatus, wherein the first metal layer is part of a first printed circuit board (PCB) and the second metal layer is part of a second PCB.

20. An apparatus comprising: an integrated circuit; a first metal layer including a first ground plane and a first loop antenna, the first metal layer being on a periphery of the integrated circuit; a second metal layer including a second ground plane and a second loop antenna, the second metal layer being on a periphery of the integrated circuit; a substrate between the first metal layer and the second metal layer; a through via in the substrate, the through via being coupled between the first loop antenna and the second loop antenna; Including, the integrated circuit at least partially overlaps the first ground plane; The substrate, the first metal layer, and the second metal layer form a stack.

21. The apparatus of claim 20, The apparatus, wherein the first loop antenna and the second loop antenna at least partially overlap one another.

22. An apparatus comprising: an integrated circuit; a first metal layer including a first ground plane and a loop antenna, the loop antenna being on a periphery of the integrated circuit; a second metal layer including a second ground plane and a serpentine antenna, the second metal layer being on a periphery of the integrated circuit; a substrate between the first metal layer and the second metal layer; a through via in the substrate, the through via being coupled between the loop antenna and the serpentine antenna; Including, the integrated circuit at least partially overlaps the first ground plane; The substrate, the first metal layer, and the second metal layer form a stack.

23. The apparatus of claim 22, The apparatus, wherein the loop antenna and the serpentine antenna at least partially overlap one another.

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