Barrett structure, radio frequency front end, chip and communication terminal

Abstract

The utility model provides a kind of balun structure, radio frequency front end, chip and communication terminal.The balun structure includes shielding ground structure layer and the main coil, secondary coil and filling structure being stacked above shielding ground structure layer;The projection of main coil and filling structure on shielding ground structure layer is located in the projection area of secondary coil on shielding ground structure layer;Main coil is configured to pass through electromagnetic coupling and transmit the energy of received radio frequency signal to secondary coil, filling structure is configured to be coupled with secondary coil to generate additional parasitic capacitance to compensate the amplitude-phase misadjustment caused by parasitic capacitance between main coil and secondary coil, so that secondary coil generates the differential signal with equal amplitude and 180 degrees phase difference.The utility model improves the structure of balun itself, can effectively improve the amplitude and phase imbalance characteristics of output port differential signal, and the radio frequency module using the utility model can significantly improve the output power of power amplifier.

Description

Technical Field

[0001] This utility model relates to the field of communication technology, and in particular to a balun structure, radio frequency front-end, chip and communication terminal. Background Technology

[0002] To overcome the problem of excessive attenuation of higher frequency signals in space, certain frequency bands of mobile terminals, such as n41 / n77, require a transmit power of Class 2 (PC2 = 26dBm), which is 3dBc higher than the traditional Class 3 (PC3 = 23dBm), effectively doubling the transmit power. For power amplifiers in these frequency bands, existing technologies typically employ power combination architectures to address this power enhancement challenge. Power combination architectures include balanced power amplifiers, differential power amplifiers, and Doherty amplifiers. Compared to other amplifier architectures, differential power amplifiers are gaining increasingly widespread application due to their simple structure, small size, and large operating bandwidth.

[0003] A common differential architecture uses a balun to convert a single signal into a dual-differential signal, characterized by identical amplitudes and a 180-degree phase difference. However, from a circuit implementation perspective, although sufficient symmetry can be guaranteed during layout, the presence of parasitic parameters means that the balun's layout structure still cannot achieve ideal differential characteristics in terms of performance.

[0004] It should be noted that the information disclosed in the background section of this utility model is intended only to enhance the understanding of the general background of this utility model, and should not be regarded as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Utility Model Content

[0005] The purpose of this invention is to provide a balun structure, an RF front-end, a chip, and a communication terminal. By improving the structure of the balun itself, this invention can effectively improve the amplitude and phase imbalance characteristics of the differential signal at the output port. The RF module using this invention can significantly improve the output power of the power amplifier.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a balun structure for a power amplifier, the balun structure comprising a shielded ground structure layer and a main coil, a secondary coil, and a filling structure stacked on top of the shielded ground structure layer; the projections of the main coil and the filling structure on the shielded ground structure layer are located within the projection area of ​​the secondary coil on the shielded ground structure layer; the main coil is configured to transfer the energy of the received radio frequency signal to the secondary coil via electromagnetic coupling, and the filling structure is configured to couple with the secondary coil to generate additional parasitic capacitance to compensate for the amplitude and phase misalignment caused by the parasitic capacitance between the main coil and the secondary coil, thereby enabling the secondary coil to generate differential signals with equal amplitude and a phase difference of 180 degrees.

[0007] Optionally, the filling structure includes one or more dummy coil segments.

[0008] Optionally, the multiple dummy coil segments may be located on the same routing layer or on multiple routing layers.

[0009] Optionally, the routing shape of the dummy coil is similar to that of the main coil and / or the secondary coil.

[0010] Optionally, the filling structure and the main coil are located on the same routing layer.

[0011] Optionally, the filling structure is integrally formed with the main coil, the first end of the main coil is used to receive the radio frequency signal, the second end of the main coil is connected to the first end of the filling structure and then coupled to the radio frequency ground, and the second end of the filling structure is suspended.

[0012] Optionally, the wiring shape of the main coil is spiral, and the filling structure is disposed inside the main coil and close to the main coil.

[0013] Optionally, the length of the filling structure is ≥ 1 / 4 of the length of the main coil.

[0014] Optionally, the wiring layer of the secondary coil is located between the wiring layer of the filling structure and the wiring layer of the primary coil.

[0015] To achieve the above objectives, the present invention also provides a radio frequency front-end, the radio frequency front-end including a differential power amplifier, the differential power amplifier including the balun structure described in any of the above claims; the balun structure is integrated on a chip or disposed in a printed circuit board.

[0016] To achieve the above objectives, the present invention also provides a chip, wherein the chip integrates the balun structure or the radio frequency front end described above.

[0017] To achieve the above objectives, the present invention also provides a communication terminal, which includes the balun structure described in any of the above claims, or the radio frequency front-end described in the above claims, or the chip described in the above claims.

[0018] Compared with existing technologies, the balun structure, RF front-end, chip, and communication terminal provided by this utility model have the following advantages: The balun structure provided by this utility model includes a shielded ground structure layer and a main coil, a secondary coil, and a filling structure stacked on top of the shielded ground structure layer; the projections of the main coil and the filling structure on the shielded ground structure layer are located within the projection area of ​​the secondary coil on the shielded ground structure layer. Therefore, by using the design method where the secondary coil completely encloses the main coil and the filling structure, on the one hand, the main coil and the secondary coil can be better electromagnetically coupled, thus laying the foundation for the main coil to more effectively transfer the energy of the received RF signal to the secondary coil, thereby improving energy transfer efficiency; on the other hand, it also allows the filling structure and the secondary coil to be better electromagnetically coupled, so that the generated additional parasitic capacitance can effectively compensate for the amplitude and phase misalignment caused by the parasitic capacitance between the main coil and the secondary coil, thereby enabling the secondary coil to generate differential signals with equal amplitude and a 180-degree phase difference. In summary, by improving the structure of the balun itself, this invention can effectively improve the amplitude and phase imbalance characteristics of the differential signal at the output port. The RF module using this invention can significantly improve the output power of the power amplifier.

[0019] Furthermore, since the RF front-end, chip, and communication terminal provided by this utility model belong to the same inventive concept as the balun structure provided by this utility model, the RF front-end, chip, and communication terminal provided by this utility model have at least all the advantages of the balun structure provided by this utility model. For details on the beneficial effects of the RF front-end, chip, and communication terminal provided by this utility model, please refer to the above description of the beneficial effects of the balun structure provided by this utility model, which will not be repeated here. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of one type of differential power amplifier in the prior art.

[0021] Figure 2 This is a schematic diagram illustrating the working principle of a balun in existing technology.

[0022] Figure 3 This is a simplified diagram of the physical structure of a balun in the prior art.

[0023] Figure 4 for Figure 3 A two-dimensional schematic diagram of the physical structure of the middle balun.

[0024] Figure 5 for Figure 3 A cross-sectional schematic diagram of the physical structure of the middle balun.

[0025] Figure 6 for Figure 3 A three-dimensional schematic diagram of the physical structure of the middle balun.

[0026] Figure 7 This is a graph showing the amplitude imbalance of the balun in the existing technology.

[0027] Figure 8 This is a phase imbalance curve of the balun in the existing technology.

[0028] Figure 9 This is a cross-sectional schematic diagram of the balun structure provided in Embodiment 1 of this utility model.

[0029] Figure 10 This is a two-dimensional structural diagram of the balun structure provided in the first embodiment of this utility model.

[0030] Figure 11 for Figure 10 A schematic diagram of the cross-section of the middle balun structure.

[0031] Figure 12 for Figure 10 A three-dimensional structural diagram of the middle balun structure.

[0032] Figure 13 This is a comparison curve of the amplitude imbalance characteristics of the balun structure provided in the first embodiment of this utility model and the amplitude imbalance characteristics of the balun in the prior art.

[0033] Figure 14 This is a comparison curve of the phase imbalance characteristics of the balun structure provided in the first embodiment of this utility model and the phase imbalance characteristics of the balun in the prior art.

[0034] Figure 15 This is a two-dimensional structural diagram of the balun structure provided in the second embodiment of the present invention.

[0035] Figure 16 for Figure 15 A schematic diagram of the cross-section of the middle balun structure.

[0036] Figure 17 for Figure 15 A three-dimensional structural diagram of the middle balun structure.

[0037] Figure 18A comparison curve of the amplitude imbalance characteristics of the balun structure provided in the second embodiment of the present invention and the amplitude imbalance characteristics of the balun in the prior art.

[0038] Figure 19 A comparison curve of the phase imbalance characteristics of the balun structure provided in the second embodiment of the present invention and the phase imbalance characteristics of the balun in the prior art.

[0039] The reference numerals in the attached figures are as follows:

[0040] Input balun-111, first power amplifier-121, second power amplifier-122, output balun-112;

[0041] Shielding structure layer - Gp, 210; main coil - Lp, 220; secondary coil - Ls, 230;

[0042] Filler structure -240, dummy coil -241, 242. Detailed Implementation

[0043] The following detailed description, in conjunction with the accompanying drawings, provides a further detailed explanation of the balun structure, radio frequency front-end, chip, and communication terminal proposed in this utility model. The advantages and features of this utility model will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, intended only to facilitate and clarify the illustration of the embodiments of this utility model. Please refer to the drawings to make the objectives, features, and advantages of this utility model more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes and to enable those skilled in the art to understand and read them, and are not intended to limit the implementation conditions of this utility model. Any modifications to the structure, changes in proportions, or adjustments to the size, provided they produce the same or similar effects and achieve the same objectives as this utility model, should still fall within the scope of the technical content disclosed in this utility model. Specific design features of this utility model disclosed herein, including, for example, specific dimensions, orientations, positions, and shapes, will be determined in part by the specific application and usage environment. Furthermore, in the embodiments described below, the same reference numerals are sometimes used across different figures to denote the same parts or parts having the same function, and their repeated descriptions are omitted. In this specification, similar reference numerals and letters are used to denote similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0044] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The singular forms “a,” “an,” and “the” include plural objects. The term “or” is generally used to mean “and / or,” the term “several” is generally used to mean “at least one,” and the term “at least two” is generally used to mean “two or more.” Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0045] It should be understood that when a component is referred to as "connected," "connected to," or "coupled to" other components, it may be directly connected to other components, or there may be intermediary components. Conversely, when a component is referred to as "directly connected" or "directly connected to" other components, there are no intermediary components.

[0046] To facilitate understanding of this utility model, before describing the specific embodiments of the balun structure, radio frequency front-end, chip, and communication terminal provided by this utility model, the main research process for proposing this utility model is briefly described as follows:

[0047] First, the structure of a differential power amplifier will be described. For an example, please refer to [link to example]. Figure 1 , Figure 1 This is a schematic diagram of the structure of one type of differential power amplifier in the prior art. Figure 1As shown, the existing differential power amplifier structure includes an input balun 111, a first power amplifier 121, a second power amplifier 122, and an output balun 112. The input balun 111 functions as a power divider, and the output balun 112 functions as a power combiner. Ideally, a single RF input signal is split into two RF signals with a 180-degree phase difference by the input balun (power divider) 111: one RF signal is input to the first power amplifier 121, amplified, and then transmitted to the output balun (power combiner) 112; the other RF signal is transmitted to the second power amplifier 122, amplified, and then transmitted to the output balun (power combiner) 112, which combines the two RF signals to output the final RF signal.

[0048] Next, combined Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 The working principle and structure of a balun in the prior art are illustrated by way of example. For example, Figure 2 This is a schematic diagram illustrating the working principle of a balun in the existing technology; Figure 3 A simplified schematic diagram of the physical structure of a balun in the prior art; Figure 4 for Figure 3 A two-dimensional schematic diagram of the physical structure of the middle balun; Figure 5 for Figure 3 A cross-sectional schematic diagram of the physical structure of the middle balun; Figure 6 for Figure 3 A three-dimensional schematic diagram of the physical structure of the middle balun. Specifically, Figure 2 In the diagram, P1 and P2 represent the input ports for radio frequency (RF) signals, P3 and P4 represent the output ports for RF signals, Z3 and Z4 represent the output loads, Cm represents the parasitic capacitance between the primary coil Lp and the secondary coil Ls, and K represents the coupling coefficient between the primary coil Lp and the secondary coil Ls. Energy transfer between the primary coil Lp and the secondary coil Ls is achieved through coupling. Please refer to [link to relevant documentation]. Figure 3 ,from Figure 3 As can be seen, the voltage expression across the load is as follows:

[0049]

[0050]

[0051] According to expressions (1) and (2), if the parasitic capacitance Cm is 0, the output of the balun will achieve ideal differential characteristics, that is, the voltage amplitudes on the two loads are equal and the phases are opposite. However, parasitic capacitance Cm is usually unavoidable, so the unbalanced characteristics of the balun in the prior art will be apparent.

[0052] Furthermore, such as Figure 4 , Figure 5 and Figure 6 As shown, existing baluns typically employ a stacked two-layer metal design, such as... Figure 4 , Figure 5 and Figure 6 As shown, the top layer of metal serves as the main coil Lp, the next layer of metal serves as the secondary coil Ls, and the bottom layer of metal serves as the shielding ground layer Gp to provide electromagnetic shielding. The first end of the main coil Lp is the input port P1, used to receive radio frequency signals, and the second end of the main coil Lp is grounded. The two output ports P2 and P3 of the secondary coil Ls are used to output differential signals, and the center point of the secondary coil Ls is grounded. Figure 4 As shown, if the linewidth of the secondary coil Ls is W, and the secondary coil Ls completely encloses the primary coil Lp, then the relationship between the linewidth of the secondary coil Ls and the width W1 of the region where the secondary coil Ls is located and the width W2 of the region where the primary coil Lp is located can be obtained by the following formula (4):

[0053] W1-W2=2W (4)

[0054] For example, the above is adopted. Figure 4 , Figure 5 , Figure 6 For the structure shown, please refer to [link to relevant documentation] for its amplitude imbalance and phase imbalance characteristics. Figure 7 and Figure 8 ,in, Figure 7 The amplitude imbalance curve of the balun in the existing technology; Figure 8 This is a diagram of the phase imbalance curve of the balun in the prior art. More specifically, Figure 7 and Figure 8 The horizontal axis represents frequency, with the unit being GHz; Figure 7 The vertical axis represents the specific value of Mag_differ (amplitude imbalance characteristic), in dB; Figure 8 The vertical axis represents the specific value of the (Phase_differ) phase imbalance characteristic, in degrees. Figure 7 and Figure 8 It can be seen that the amplitude imbalance and phase imbalance characteristics of the balun in the existing technology show a trend of first increasing and then decreasing with the frequency.

[0055] Furthermore, the amplitude imbalance characteristics and phase imbalance characteristics can be calculated using the following equations (5) and (6), respectively:

[0056] Mag_differ=20*log|S(2,1)|-20*log|S(3,1)| (5) Phase_differ=arctan(imag(S(2,1)) / real(S(2,1)))-

[0057] arctan(imag(S(3,1)) / real(S(3,1)))(6)

[0058] In equations (5) and (6) above, Mag_differ represents the amplitude imbalance characteristic (note that the expression is given in decibels (dB), and Phase_differ represents the phase imbalance characteristic; 1, 2, and 3 correspond to...). Figure 4 The input port P1, output port P2, and output port P3 are shown in the diagram.

[0059] Therefore, it can be seen that although differential power amplifiers can theoretically increase the output power by 3dBc compared to single-channel power amplifiers, the parasitic parameters in implementing baluns prevent them from having ideal differential characteristics, resulting in imbalance between the two outputs and even seriously affecting the output power.

[0060] Based on the above research, the core idea of ​​this utility model is to provide a balun structure, an RF front-end, a chip, and a communication terminal. By improving the structure of the balun itself, this utility model can effectively improve the amplitude and phase imbalance characteristics of the differential signal at the output port. The RF module using this utility model can significantly improve the output power of the power amplifier.

[0061] It should be noted that, based on the description herein, those skilled in the art should understand that the balun structure provided by this invention can be used on the radio frequency front-end or communication terminal provided by this invention, or integrated on the chip provided by this invention; the balun structure, radio frequency front-end, and chip provided by this invention can be used on the communication terminal provided by this invention. Furthermore, the balun structure, radio frequency front-end, and chip provided by this invention are also applicable to other application scenarios of radio frequency integrated circuits besides communication terminals, for example, these scenarios include, but are not limited to, communication base stations.

[0062] Example 1

[0063] This embodiment provides a balun structure for a power amplifier. For an example, please refer to... Figure 9 , Figure 9 This is a schematic cross-sectional view of the balun structure provided in this embodiment. Figure 9 It can be seen that the balun structure includes a shielding ground structure layer 210 and a main coil 220, a secondary coil 230, and a filling structure 240 stacked on top of the shielding ground structure layer 210; the main coil 220 and the filling structure 240 ( Figure 9 The diagram illustrates dummy coils 241 and 242. The dashed lines used for illustrative purposes are for reference only. Other methods can also be used; for example, the filling structure 240 could be located in a different location. Figure 9 The projection of the other trace layers shown on the shielding structure layer 210 is located within the projection area of ​​the secondary coil 230 on the shielding structure layer 210; the main coil 220 is configured to transfer the energy of the received radio frequency signal to the secondary coil 230 through electromagnetic coupling, and the filling structure 240 is configured to couple with the secondary coil 230 to generate additional parasitic capacitance to compensate for the amplitude and phase misalignment caused by the parasitic capacitance between the main coil 220 and the secondary coil 230, thereby enabling the secondary coil 230 to generate differential signals with equal amplitude and 180-degree phase difference.

[0064] Therefore, the balun structure provided by this utility model includes a shielding structure layer 210 and a main coil 220, a secondary coil 230, and a filling structure 240 stacked on the shielding structure layer 210. The projections of the main coil 220 and the filling structure 240 on the shielding structure layer 210 are located within the projection area of ​​the secondary coil 230 on the shielding structure layer 210. Thus, by adopting the design method in which the secondary coil 230 completely encloses the main coil 220 and the filling structure 240, it is possible to ensure that the main coil 220 and the secondary coil... The improved electromagnetic coupling of the secondary coil 230 allows the primary coil 220 to more effectively transfer the energy of the received radio frequency signal to the secondary coil 230, thereby improving energy transfer efficiency. Furthermore, it also enables better electromagnetic coupling between the filling structure 240 and the secondary coil 230, allowing the additional parasitic capacitance to effectively compensate for the amplitude and phase imbalance caused by the parasitic capacitance between the primary coil 220 and the secondary coil 230. This allows the secondary coil 230 to generate differential signals with equal amplitude and a 180-degree phase difference. In summary, by improving the structure of the balun, this invention effectively improves the amplitude and phase imbalance characteristics of the differential signal at the output port. The radio frequency module using this invention can significantly increase the output power of the power amplifier.

[0065] Exemplary examples show that in some exemplary embodiments, the main coil 220 is located in the topmost metal layer, the secondary coil 230 is located in the second-to-topmost metal layer, and the shielding ground structure layer 210 is located in the bottommost metal layer. This invention does not limit the number of metal layers; they should be reasonably arranged according to actual needs when implementing this invention. Furthermore, this invention does not impose excessive limitations on the specific location of the main coil 220. For example, in a three-dimensional plane, the edge of the main coil 220 may or may not be flush with the edge of the secondary coil 230. Additionally, it is understood that the shielding ground structure layer 210 is used to provide electromagnetic shielding.

[0066] Exemplary examples include, in some of the exemplary embodiments, the filler structure 240 includes a dummy coil. This dummy coil design of the filler structure 240 not only facilitates coupling between the filler structure 240 and the secondary coil 230, thereby better compensating for amplitude and phase misalignment caused by parasitic capacitance between the primary coil 220 and the secondary coil 230, thus enabling the secondary coil 230 to generate differential signals with equal amplitude and a 180-degree phase difference; but also effectively reduces the production and manufacturing costs of the balun structure by using a dummy coil in the filler structure.

[0067] Exemplary, in some other exemplary embodiments, the filler structure 240 may include multiple dummy coil segments. Therefore, the use of multiple dummy coil segments in the filler structure 240 not only facilitates coupling between the filler structure 240 and the secondary coil 230, thus better compensating for the amplitude and phase misalignment caused by the parasitic capacitance between the primary coil 220 and the secondary coil 230, but also enables the secondary coil 230 to generate differential signals with equal amplitude and a 180-degree phase difference, further improving the performance of the balun structure provided by this invention.

[0068] It should be noted that those skilled in the art should understand that the use of one or more dummy coils to implement the filling structure 240 described herein is merely an illustrative example of a preferred embodiment and not a limitation of this invention. This invention does not impose excessive limitations on the routing shape of the filling structure 240. In other embodiments, the filling structure 240 may also be other routing shapes besides dummy coils. For example, the filling structure 240 may also be, but is not limited to, a zigzag shape or a ring shape.

[0069] Based on the foregoing description, it is clear that the use of a dummy coil in the filling structure 240 described in the relevant figures of the <First Embodiment> and <Second Embodiment> of this example is merely an example, intended only to facilitate understanding and illustration of this utility model, and is not a limitation thereof.

[0070] Exemplary examples show that in some of these exemplary embodiments, multiple dummy coil segments are located on the same trace layer. Therefore, by placing multiple dummy coil segments on the same trace layer (metal layer), it is not only easier for the filler structure 240 to couple with the secondary coil 230, thereby better compensating for the amplitude and phase misalignment caused by the parasitic capacitance between the primary coil 220 and the secondary coil 230, but also enables the secondary coil 230 to generate differential signals with equal amplitude and a 180-degree phase difference. This further improves the performance of the balun structure provided by this invention and effectively reduces the design complexity of the balun structure, thus saving costs.

[0071] Exemplary examples show that, in other exemplary embodiments, multiple segments of the dummy coil are located on multiple routing layers. Thus, by placing multiple segments of the dummy coil on multiple different routing layers, the coupling effect between the dummy coil and the secondary coil 230 can be further improved, thereby further enhancing the accuracy of the balun structure.

[0072] It should be noted that those skilled in the art should understand that if a design is adopted in which multiple dummy coils are located on multiple routing layers, this invention does not limit the number of routing layers on which the dummy coils are located, and the routing layers on which the dummy coils are located can be two, three, or more. Furthermore, for a routing layer on which the dummy coils are located, one, two, three, or more dummy coils can be located; and further still, for a routing layer with multiple dummy coils, the dummy coils located thereon can be adjacent or not adjacent, and this invention does not limit the positional relationship between the dummy coils.

[0073] For example, in some preferred embodiments, the routing shape of the dummy coil is similar to that of the main coil 220 (for example, please refer to the relevant drawings in the <First Embodiment> or <Second Embodiment> below). Thus, by setting the routing shape of the dummy coil to be similar to that of the main coil 220, it is easier for the secondary coil 230 to completely enclose the main coil 220 and the filling structure 240, thereby reducing the complexity of the design and making it easier to apply and implement this invention.

[0074] Exemplarily, in some other preferred embodiments, the routing shape of the dummy coil is similar to that of the secondary coil 230 (exemplarily, see the relevant figures in the <First Embodiment> or <Second Embodiment> below). Therefore, by designing the routing shape of the dummy coil to be similar to that of the secondary coil 230, the coupling performance between the dummy coil and the secondary coil 230 can be further improved, thereby better compensating for the amplitude and phase misalignment caused by the parasitic capacitance between the primary coil 220 and the secondary coil 230. This allows the secondary coil 230 to generate differential signals with equal amplitude and a 180-degree phase difference, further improving the performance of the balun structure provided by this invention.

[0075] It should be noted that those skilled in the art should understand that the main purpose of the dummy coil is to improve the amplitude and phase characteristics of the balun structure. Therefore, this invention does not impose excessive limitations on the length, width, and shape of the dummy coil traces. The length, width, and / or shape of the dummy coil traces can be the same as or different from the length, width, and shape of the main coil 220 and / or the secondary coil 230.

[0076] To facilitate understanding and explanation of this utility model, the following <First Embodiment> and <Second Embodiment> exemplify the balun structure provided by this utility model by taking the filling structure 240 including a dummy coil as an example. However, it should be understood that the accompanying drawings in the <First Embodiment> and <Second Embodiment> are merely illustrative examples of preferred embodiments and not limitations thereof.

[0077] <First Implementation Method>

[0078] For example, please see Figure 10 , Figure 11 and Figure 12 ,in, Figure 10This is a two-dimensional structural diagram of the balun structure provided in this embodiment. Figure 11 for Figure 10 Schematic diagram of the cross section of the middle balun structure. Figure 12 for Figure 10 A three-dimensional structural diagram of the middle Baron structure. From... Figure 10 , Figure 11 and Figure 12 As can be seen, in this embodiment, the filling structure 240 ( Figure 10 , Figure 11 and Figure 12 In the example of the dummy coil 241, the main coil 220 is located on the same trace layer. Therefore, by placing the filler structure 240 and the main coil 220 on the same trace layer (metal layer), on the one hand, it can effectively ensure electromagnetic coupling between the filler structure 240 (i.e., the dummy coil 241) and the secondary coil 230 without increasing the metal trace layer of the balun structure, thereby better compensating for the amplitude and phase misalignment caused by the parasitic capacitance between the main coil 220 and the secondary coil 230. On the other hand, it can also effectively reduce the design complexity of the balun structure, thereby effectively saving costs.

[0079] For example, please continue to see Figure 10 , Figure 11 and Figure 12 ,from Figure 10 , Figure 11 and Figure 12 It can be seen that in some exemplary embodiments, the filling structure 240 ( Figure 10 , Figure 11 and Figure 12 The dummy coil 241 (example) is integrally formed with the main coil 220. The first end P1 of the main coil 220 is used to receive the radio frequency signal, and the second end of the main coil 220 is connected to the filling structure 240 (example). Figure 10 , Figure 11 and Figure 12 In the example of the dummy coil 241, the first end is connected to the radio frequency ground, and the second end of the filling structure 240 is left floating. Thus, using the filling structure 240 (… Figure 10 , Figure 11 and Figure 12 The design of the dummy coil 241 (example) being integrally formed with the main coil 220 can further simplify the design complexity of this utility model and further reduce costs.

[0080] For example, such as Figure 10 and Figure 12As shown, for the secondary coil 230, the first terminal P2 and the second terminal P3 of the secondary coil 230 are close to each other and are used to output differential signals, respectively. The midpoint of the secondary coil 230 is coupled to radio frequency ground GND1. Therefore, by using the design of coupling the midpoint of the secondary coil 230 to radio frequency ground GND1, the first terminal P2 and the second terminal P3 of the secondary coil 230 can be symmetrically arranged, thereby further improving the amplitude and phase characteristics of the balun structure provided by this invention. Furthermore, from... Figure 10 It can also be seen that the trace length of the first end P1 of the main coil 220 exceeds the trace length of the first end P2 and the second end P3 of the secondary coil 230. This is more conducive to the electromagnetic coupling between the main coil 220 and the secondary coil 230, thereby further improving the transmission efficiency of the radio frequency signal.

[0081] For example, please continue to see Figure 10 and Figure 12 ,from Figure 10 and Figure 12 As can be seen, in some exemplary embodiments, the routing shape of the main coil 220 is helical, and the filling structure 240 is disposed inside and close to the main coil 220. Thus, by designing the routing shape of the main coil 220 as helical and placing the filling structure 240 (… Figure 10 , Figure 11 and Figure 12 The dummy coil 241 (example) is placed inside and close to the main coil 220, which can effectively reduce the size of the balun structure, thereby further improving the applicability of this utility model.

[0082] Exemplary, in some exemplary embodiments, the filling structure 240 ( Figure 10 , Figure 11 and Figure 12 The length of the dummy coil 241 (example) is ≥ 1 / 4 of the length of the main coil 220. Therefore, the filling structure 240 (example) is used. Figure 10 , Figure 11 and Figure 12 The design of using a dummy coil 241 (example) with a length ≥ 1 / 4 of the length of the main coil 220 effectively ensures that the filling structure 240 (example) Figure 10 , Figure 11 and Figure 12The additional parasitic capacitance generated by the electromagnetic coupling between the dummy coil 241 (example) and the secondary coil 230 better compensates for the amplitude and phase mismatch caused by the parasitic capacitance between the primary coil 220 and the secondary coil 230, enabling the secondary coil 230 to generate differential signals with equal amplitude and 180-degree phase difference, thereby effectively improving the amplitude and phase imbalance characteristics of the differential signal at the output port.

[0083] To more intuitively demonstrate the beneficial effects of the balun structure provided in this embodiment, please refer to the example provided. Figure 13 and Figure 14 ,in, Figure 13 A comparison curve of the amplitude imbalance characteristics of the balun structure provided in this embodiment and the amplitude imbalance characteristics of the balun in the prior art. Figure 14 A comparison curve showing the phase imbalance characteristics of the balun structure provided in this embodiment with those of baluns in the prior art. More specifically, Figure 13 and Figure 14 The horizontal axis represents frequency, with the unit being GHz; Figure 13 The vertical axis represents the specific value of Mag_differ (amplitude imbalance characteristic), in dB; Figure 14 The vertical axis represents the specific value of the (Phase_differ) phase imbalance characteristic, in degrees; furthermore, Figure 13 In the figure, red represents the amplitude imbalance characteristic curve of the balun in the prior art, and blue represents the amplitude imbalance characteristic curve of the balun structure provided in this embodiment. Figure 14 In the diagram, red represents the phase imbalance characteristic curve of a balun in the prior art, and blue represents the phase imbalance characteristic curve of the balun structure provided in this embodiment. (Combined with...) Figure 13 and Figure 14 It is not difficult to conclude that within the frequency band of interest, the balun structure provided by this invention will significantly improve both amplitude imbalance and phase imbalance characteristics.

[0084] <Second Implementation Method>

[0085] The balun structure provided in this embodiment is based on the same principle as the balun structure provided in the first embodiment. To avoid redundancy, only the differences between the balun structure provided in this embodiment and the first embodiment will be described below. For parts not described in this embodiment, please refer to the corresponding description in the <First Embodiment> for an adaptive understanding. For example, please refer to Figure 15 , Figure 16 and Figure 17 ,in, Figure 15 This is a two-dimensional structural diagram of the balun structure provided in this embodiment. Figure 16 for Figure 15 Schematic diagram of the cross section of the middle balun structure. Figure 17 for Figure 15 A three-dimensional structural diagram of the middle Baron structure. From... Figure 15 , Figure 16 and Figure 17 It can be seen that the balun structure provided in this embodiment differs from the <first embodiment> in that: the wiring layer of the secondary coil 230 in the balun structure provided in this embodiment is located in the filling structure 240 ( Figure 15 , Figure 16 and Figure 17 The trace layer of the dummy coil 242 (example) is located between the trace layer of the primary coil 220 and the trace layer of the secondary coil 230. Thus, the trace layer of the secondary coil 230 is located within the filler structure 240 (example). Figure 15 , Figure 16 and Figure 17 The design of the trace layer of the dummy coil 242 (example) and the trace layer of the main coil 220 facilitates, on the one hand, the electromagnetic coupling between the secondary coil 230 and the main coil 220 to generate a differential signal, thereby improving energy transfer efficiency; on the other hand, it also facilitates the interaction between the secondary coil 230 and the filling structure 240 (example). Figure 15 , Figure 16 and Figure 17 The coupling of the dummy coil 242 (example) further improves the amplitude and phase characteristics. In addition, this modular design makes it easier to implement this utility model.

[0086] For example, please continue to see Figure 15 and Figure 17 ,from Figure 15 and Figure 17 It can be seen that in some exemplary embodiments, the filling structure 240 ( Figure 15 , Figure 16 and Figure 17 The trace shape of the dummy coil 242 (example) is consistent with the trace shape of the main coil 220. This, on the one hand, makes it easier to flexibly design the filling structure 240 (…). Figure 10 , Figure 11 and Figure 12 The position and routing shape of the dummy coil 242 (example) can improve the filling structure 240 ( Figure 10 , Figure 11 and Figure 12The additional parasitic capacitance generated by the electromagnetic interaction between the dummy coil 242 and the secondary coil 230 compensates for the amplitude-phase imbalance caused by the parasitic capacitance between the primary coil 220 and the secondary coil 230, thereby improving the amplitude-phase imbalance performance of the balun structure provided by this invention; on the other hand, it can also further enhance the applicability of this invention.

[0087] Exemplarily, in some preferred embodiments, the filling structure 240 ( Figure 10 , Figure 11 and Figure 12 The routing shape of the dummy coil 242 (example) is the same as that of the main coil 220, thereby further improving the compensation effect of the filling structure 240 on the amplitude and phase misalignment caused by the parasitic capacitance between the main coil 220 and the secondary coil 230.

[0088] To more intuitively demonstrate the beneficial effects of the balun structure provided in this embodiment, please refer to the example provided. Figure 18 and Figure 19 ,in, Figure 18 A comparison curve of the amplitude imbalance characteristics of the balun structure provided in this embodiment and the amplitude imbalance characteristics of the balun in the prior art. Figure 19 A comparison curve showing the phase imbalance characteristics of the balun structure provided in this embodiment with those of baluns in the prior art. More specifically, Figure 18 and Figure 19 The horizontal axis represents frequency, with the unit being GHz; Figure 18 The vertical axis represents the specific value of Mag_differ (amplitude imbalance characteristic), in dB; Figure 19 The vertical axis represents the specific value of the (Phase_differ) phase imbalance characteristic, in degrees. Figure 18 In the figure, red represents the amplitude imbalance characteristic curve of the balun in the prior art, and blue represents the amplitude imbalance characteristic curve of the balun structure provided in this embodiment. Figure 19 In the diagram, red represents the phase imbalance characteristic curve of a balun in the prior art, and blue represents the phase imbalance characteristic curve of the balun structure provided in this embodiment. (Combined with...) Figure 18 and Figure 19 It is not difficult to conclude that within the frequency band of interest, the balun structure provided by this invention will significantly improve both amplitude imbalance and phase imbalance characteristics.

[0089] Based on the description herein, those skilled in the art should understand that the main difference between the balun structure provided by this invention and baluns in the prior art is that the balun structure provided by this invention also includes a filling structure. Therefore, for more detailed information regarding the balun structure not mentioned herein, please refer to the relevant descriptions of baluns in the prior art known to those skilled in the art for an appropriate understanding.

[0090] Example 2

[0091] This embodiment provides a radio frequency (RF) front-end. The RF front-end includes a differential power amplifier, which comprises the balun structure described in any of the embodiments of this embodiment; in some embodiments, the balun structure is integrated on a chip. Therefore, by implementing the balun structure at the wafer-level, the integration density of the RF front-end provided by this invention can be effectively improved. In other embodiments, the balun structure is disposed in a printed circuit board (PCB). Therefore, disposing of the balun structure in a printed circuit board helps to reduce costs. It should be noted that those skilled in the art should understand that the above description of the balun structure being based on a chip or disposed in a printed circuit board is merely an exemplary description of preferred embodiments and not a limitation of this invention. This invention does not limit the integration method of the balun structure.

[0092] Furthermore, since the radio frequency front-end provided by this utility model includes a differential power amplifier, and the differential power amplifier includes the balun structure provided by this utility model, the radio frequency front-end provided by this utility model has at least all the advantages of the balun structure provided by this utility model. For details on the beneficial effects of the radio frequency front-end provided by this utility model, please refer to the above description of the beneficial effects of the balun structure provided by this utility model, which will not be repeated here.

[0093] It should also be noted that, in addition to the differential power amplifier, the RF front-end provided in this embodiment may also include a control unit, a power supply unit, a detection unit, and a switching unit. The RF front-end is used to transmit the RF signal amplified by the differential power amplifier to the antenna, which then transmits it to the communication base station, thereby enabling the RF front-end to send the RF signal to the communication base station. For more detailed information about the RF front-end, please refer to the relevant technical adaptations known to those skilled in the art; due to space limitations, this will not be elaborated upon further here.

[0094] It should be noted that the functional modules of the radio frequency front end can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part. This utility model does not impose any limitations in this regard.

[0095] Example 3

[0096] This embodiment provides a chip, in some embodiments of which the chip integrates the balun structure described in any embodiment of Embodiment 1 of this document; in other embodiments, the chip integrates the radio frequency front-end described in Embodiment 2 of this document.

[0097] This utility model does not limit the manufacturing process, application field, or function of the chip. For example, the chip can be, but is not limited to, a 7nm chip, a 14nm chip, or a 28nm chip; the chip can be, but is not limited to, automotive chips and consumer electronics chips, etc.

[0098] Example 4

[0099] This embodiment provides a communication terminal, which includes the balun structure described in any of the embodiments of this embodiment one, the radio frequency front-end described in embodiment two, or the chip described in embodiment three.

[0100] It should be understood that this utility model does not impose excessive limitations on the communication terminal. For example, the communication terminal can be a computer device used in a mobile environment and supports multiple communication standards, including but not limited to GSM, EDGE, TD-SCDMA, TDD-LTE, and FDD-LTE. For example, the communication terminal includes, but is not limited to, mobile phones, laptops, tablets, and in-vehicle computers.

[0101] The balun structure, RF front-end, chip, and communication terminal provided by this utility model have the following advantages: The balun structure provided by this utility model includes a shielded ground structure layer and a main coil, a secondary coil, and a filling structure stacked on top of the shielded ground structure layer; the projections of the main coil and the filling structure on the shielded ground structure layer are located within the projection area of ​​the secondary coil on the shielded ground structure layer. Therefore, by using the design method where the secondary coil completely encloses the main coil and the filling structure, on the one hand, the main coil and the secondary coil can be better electromagnetically coupled, thus laying the foundation for the main coil to more effectively transfer the energy of the received RF signal to the secondary coil, thereby improving energy transfer efficiency; on the other hand, it also allows the filling structure and the secondary coil to be better electromagnetically coupled, so that the generated additional parasitic capacitance can effectively compensate for the amplitude and phase misalignment caused by the parasitic capacitance between the main coil and the secondary coil, thereby enabling the secondary coil to generate differential signals with equal amplitude and a 180-degree phase difference. In summary, by improving the structure of the balun itself, this invention can effectively improve the amplitude and phase imbalance characteristics of the differential signal at the output port. The RF module using this invention can significantly improve the output power of the power amplifier.

[0102] The above description is merely a description of preferred embodiments of the balun structure, radio frequency front-end, chip, and communication terminal provided by this utility model, and is not intended to limit the scope of this utility model in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of this utility model. Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of this utility model and its equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A balun structure for a power amplifier, characterized in that, The balun structure includes a shielded ground structure layer and a main coil, a secondary coil, and a filler structure stacked on top of the shielded ground structure layer. The projections of the main coil and the filler structure onto the shielded ground structure layer are located within the projection area of ​​the secondary coil onto the shielded ground structure layer. The main coil is configured to transfer the energy of the received radio frequency signal to the secondary coil via electromagnetic coupling. The filler structure is configured to couple with the secondary coil to generate additional parasitic capacitance to compensate for the amplitude and phase misalignment caused by the parasitic capacitance between the main coil and the secondary coil, thereby enabling the secondary coil to generate differential signals with equal amplitude and 180-degree phase difference.

2. The balun structure according to claim 1, characterized in that, The filling structure includes one or more dummy coil segments.

3. The balun structure according to claim 2, characterized in that, The multiple dummy coils described herein are located on the same routing layer or on multiple routing layers.

4. The balun structure according to claim 2, characterized in that, The routing shape of the dummy coil is similar to that of the main coil and / or the secondary coil.

5. The balun structure according to claim 1, characterized in that, The filling structure and the main coil are located on the same routing layer.

6. The balun structure according to claim 5, characterized in that, The filling structure is integrally formed with the main coil. The first end of the main coil is used to receive the radio frequency signal. The second end of the main coil is connected to the radio frequency ground after being connected to the first end of the filling structure. The second end of the filling structure is suspended.

7. The balun structure according to claim 6, characterized in that, The main coil has a spiral-shaped wiring, and the filling structure is located inside the main coil and close to it.

8. The balun structure according to claim 6, characterized in that, The length of the filling structure is ≥ 1 / 4 of the length of the main coil.

9. The balun structure according to claim 1, characterized in that, The secondary coil's wiring layer is located between the wiring layer of the filling structure and the wiring layer of the primary coil.

10. A radio frequency front end, characterized in that, The radio frequency front end includes a differential power amplifier, which includes a balun structure as described in any one of claims 1 to 9; the balun structure is integrated on a chip or disposed in a printed circuit board.

11. A chip, characterized in that, It integrates a balun structure as described in any one of claims 1 to 9 or a radio frequency front-end as described in claim 10.

12. A communication terminal, characterized in that, This includes the balun structure as described in any one of claims 1 to 9, the radio frequency front end as described in claim 10, or the chip as described in claim 11.

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