Coupler and radio frequency front end module
By designing a multi-layered coupler, using a high-resistivity silicon substrate and a specific waveguide structure, the problems of signal monitoring error and equipment miniaturization in the Sub-3G band were solved, achieving low power consumption, high-precision signal sampling, and equipment stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- LANSUS TECH INC
- Filing Date
- 2026-06-05
- Publication Date
- 2026-08-04
AI Technical Summary
Existing couplers in the Sub-3G frequency band suffer from problems such as prominent parasitic inductance or capacitance, large signal transmission loss, drastic changes in coupling degree with frequency, large size, and strong dependence on isolation characteristics, resulting in large signal monitoring errors and difficulty in miniaturizing equipment.
Design a multilayer coupler using a substrate with a high-resistivity silicon substrate, an oxide insulating layer, and a multi-metal layer, combined with a specific waveguide structure including input, coupling, isolation, and transition waveguides. Optimize the design to reduce parasitics, improve stability, and lower power consumption.
It achieves low parasitic, narrowband, high-precision signal sampling, reduces power consumption, ensures the accuracy of signal monitoring and the miniaturization of equipment, and improves communication stability and battery life.
Smart Images
Figure CN122338392B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of communication technology, and in particular to a coupler and a radio frequency front-end module. Background Technology
[0002] Sub-3G (0.7-1.0GHz band) LB (Low Band) is a core frequency band for low-power communication in IoT (Internet of Things) and wide-coverage mobile communication. In communication systems, the sub-3G band has become a core frequency band for ensuring basic communication and wide-area coverage due to its characteristics of low signal propagation loss and wide coverage.
[0003] As a key component in the radio frequency transmission link, the power amplifier (PA) directly determines communication quality and battery life through its output power, efficiency, and linearity. Therefore, it is necessary to monitor the output signal of the power amplifier in real time through a coupler to achieve closed-loop control. However, monitoring the power amplifier signal in the sub-3G band requires solving three key problems: ultra-low frequency parasitic interference, narrowband high-stability sampling, and low-power adaptation.
[0004] Couplers in related technologies have the following drawbacks: 1. Couplers based on circuit boards or substrates have prominent parasitic inductance or capacitance when integrated with power amplifier chips. The transmission loss in the sub-3G band exceeds 1.2dB, and the signal-to-noise ratio of the detected signal is less than 22dB, which cannot meet the accurate sampling requirements of the power amplifier for weak signals.
[0005] 2. The wavelength of the sub-3G band is relatively long, reaching 30-43cm. The coupling degree of the planar coupling structure changes drastically with the frequency. The coupling degree difference in the sub-3G band exceeds 6dB, which will lead to an in-band monitoring error of more than 18%.
[0006] 3. To meet the broadband requirements of the sub-3G frequency band, the coupler needs to be increased in size to achieve stable mode propagation, which contradicts the development trend of miniaturization and high-density integration of electronic devices.
[0007] 4. The isolation characteristics of the coupler are highly frequency band dependent. The isolation effect of the coupler varies greatly for signals in the sub-3G frequency band that are different from those in the sub-3G frequency band, and it is easily affected by interference, which can lead to monitoring distortion.
[0008] For example, in electronic devices such as mobile phones in the Sub-3G LB band, the frequency dependence of coupling causes the power amplifier to have a power control error of more than 10% when switching between the 0.8GHz (GSM 850) and 0.9GHz (GSM 900) bands, which can easily lead to signal overflow or communication interruption; GSM stands for Global System for Mobile Communications.
[0009] Therefore, there is an urgent need for a coupler with low parasitics, narrowband high and stable sampling, and low power consumption adaptation. Summary of the Invention
[0010] To address the shortcomings of the aforementioned technologies, this invention proposes a coupler with low parasitics, narrowband high and stable sampling, and low power consumption adaptation.
[0011] To address the aforementioned technical problems, in a first aspect, the present invention provides a coupler comprising a substrate and an input waveguide, a switching waveguide, a coupling waveguide, an isolation waveguide, a transition waveguide, and an output port line respectively formed on the substrate; The substrate is formed by stacking multiple layers, including a high-resistivity silicon substrate, an oxide insulating buried layer, a first metal layer, a second metal layer and a third metal layer stacked sequentially; the second metal layer is provided with a plurality of first metal vias that penetrate through it along the stacking direction of the substrate and are spaced apart from each other; the resistivity of the high-resistivity silicon substrate is greater than 3000 Ω•cm. The input waveguide, the coupling waveguide, the isolation waveguide, and the output port line are spaced apart from each other and formed on the third metal layer, while the jump waveguide and the transition waveguide are spaced apart from each other and formed on the second metal layer. The input waveguide is wound 1.5 times, the coupling waveguide starts from one side of the input waveguide and wound 2.5 times, the isolation waveguide is disposed on the other side of the input waveguide, the output port line and the coupling waveguide are located on the same side of the input waveguide, and the output port line is further away from the input waveguide relative to the coupling waveguide; the first portion of the coupling waveguide is coupled to the input waveguide, and the orthographic projection of the first portion of the coupling waveguide perpendicular to the stacking direction of the substrate completely falls into the input waveguide; the first portion of the isolation waveguide is coupled to the input waveguide, and the orthographic projection of the first portion of the isolation waveguide perpendicular to the stacking direction of the substrate completely falls into the input waveguide; The outer end of the input waveguide serves as the input end of the coupler, the outer end of the coupling waveguide serves as the coupling end of the coupler, one end of the isolation waveguide serves as the isolation end of the coupler, and the output port line serves as the output end of the coupler. The two ends of the jump waveguide are respectively connected to the inner end of the input waveguide and the output port line through two first metal through holes; the jump waveguide is provided with a plurality of through holes that pass through it along the stacking direction of the substrate and are spaced apart from each other, and each through hole extends along the direction of the output port line near the inner end of the input waveguide. The two ends of the transition waveguide are respectively connected to the inner end of the coupling waveguide and the other end of the isolation waveguide through two first metal through holes, and the orthogonal projection portion of the transition waveguide along the stacking direction of the substrate overlaps with the coupling waveguide.
[0012] Preferably, the thickness of the high-resistivity silicon substrate is 300±10μm; the thickness of the oxide insulating buried layer is 0.47μm; and the dielectric constant of the oxide insulating buried layer is 4.1.
[0013] Preferably, the material of the first metal layer is Cu, and the thickness of the first metal layer is 0.29±0.05μm; the material of the second metal layer is Cu, and the thickness of the second metal layer is 0.32±0.05μm; the material of the third metal layer is Al, and the thickness of the third metal layer is 4±0.05μm.
[0014] Preferably, the width of the input waveguide and the width of the jumper waveguide are the same, both being 40±5μm; the width of the coupling waveguide and the isolation waveguide are the same, both being 10±5μm.
[0015] Preferably, the area of the overlap between the orthographic projection of the transition waveguide along the stacking direction of the substrate and the coupling waveguide is 1500 μm. 2 -2000μm 2 .
[0016] Preferably, the distance between two adjacent perforations is less than 8 μm, and the width of each perforation along its extension direction is 10 ± 1 μm.
[0017] Preferably, the distance between the coupling waveguide and the input waveguide is less than 6 μm, and the distance between the isolation waveguide and the input waveguide is less than 6 μm.
[0018] Preferably, the sum of the area of the portion of the coupling waveguide projected along the stacking direction perpendicular to the substrate and falling onto the input waveguide and the area of the portion of the isolation waveguide projected along the stacking direction perpendicular to the substrate and falling onto the input waveguide is 4-6% of the area of the metal region composed of the input waveguide, the coupling waveguide, and the isolation waveguide.
[0019] In a second aspect, the present invention provides a radio frequency front-end module, which includes a coupler as described above, a power amplifier formed on the substrate, a frequency band selection switch, a frequency band filter, an antenna switch, a first capacitor, a first resistor, a monitoring circuit (DET), an isolation matching circuit, an inductor, and an antenna. The input terminal of the power amplifier is used to receive radio frequency signals; The first terminal of the frequency band selection switch is connected to the output terminal of the power amplifier and is used to select the frequency band signal to pass. The input terminal of the frequency band filter is connected to the second terminal of the frequency band selection switch and is used to filter the received frequency band signal. The input terminal of the antenna switch is connected to the output terminal of the frequency band filter and is used to select the frequency band signal to pass. The input terminal of the coupler is connected to the output terminal of the antenna switch; The first terminal of the first capacitor is connected to the coupling terminal of the coupler; The first end of the first resistor is connected to the second end of the first capacitor, and the second end of the first resistor is grounded. The input terminal of the monitoring circuit is connected to the second terminal of the first capacitor, and the output terminal of the monitoring circuit is used to output a voltage monitoring signal. The isolation matching circuit includes a plurality of second resistors and a number of second capacitors equal to the number of the second resistors; the first ends of the plurality of second resistors and the first ends of the plurality of second capacitors are respectively connected to the isolation end of the coupler, and the second ends of the plurality of second resistors and the second ends of the plurality of second capacitors are connected together and grounded; The first end of the inductor is connected to the output end of the coupler, and the second end of the inductor is grounded; The input terminal of the antenna is connected to the output terminal of the coupler, and the antenna is used to output or receive radio frequency signals.
[0020] Compared with related technologies, the coupler of the present invention, through the design of a substrate, an input waveguide, a jumper waveguide, a coupling waveguide, an isolation waveguide, a transition waveguide, and an output port line formed on the substrate, and the coupling waveguide starting from one side of the input waveguide and wrapping around the input waveguide 2.5 times, the first part of the coupling waveguide is coupled to the input waveguide, the first part of the isolation waveguide is coupled to the input waveguide, and multiple through holes are provided on the jumper waveguide so that the orthographic projection of the transition waveguide along the stacking direction of the substrate overlaps with the coupling waveguide, thereby enabling the coupler to have low parasitics, high narrowband, stable sampling, and low power consumption. Attached Figure Description
[0021] The present invention will now be described in detail with reference to the accompanying drawings. The above and other aspects of the present invention will become clearer and more readily understood through the detailed description following the accompanying drawings. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the coupler provided in an embodiment of the present invention, shown in perspective. Figure 2 A structural plan view of the second and third metal layers in the coupler provided in an embodiment of the present invention; Figure 3 A three-dimensional structural diagram of the second and third metal layers in the coupler provided in an embodiment of the present invention; Figure 4 Insertion loss curves of the coupler at different frequency bands provided in embodiments of the present invention; Figure 5 The coupling accuracy of the coupler provided in this embodiment of the invention at a frequency of 915MHz is shown in the curves of different phases when the antenna voltage standing wave ratio (VSWR) is 5:1; Figure 6 A schematic diagram of the radio frequency front-end module provided in an embodiment of the present invention; Figure 7 The curves showing the coupling coefficient, directivity, and isolation of the coupler in the radio frequency front-end module provided in the embodiments of the present invention. Detailed Implementation
[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.
[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0025] Example 1 This invention provides a coupler 100, which combines... Figures 1 to 5 As shown, it includes a substrate 1 and an input waveguide 151, a jumper waveguide 142, a coupling waveguide 152, an isolation waveguide 153, a transition waveguide 143, and an output port line 154, which are respectively formed on the substrate 1.
[0026] Coupler 100 is implemented based on SOI (Silicon-On-Insulator) technology; Coupler 100 is applied in the 0.7-1.0 GHz frequency band.
[0027] The substrate 1 is formed by a multilayer structure, which includes a high-resistivity silicon substrate 11, an oxide insulating buried layer 12 (BOX), a first metal layer 13, a second metal layer 14 and a third metal layer 15 stacked sequentially.
[0028] The resistivity of the high-resistivity silicon substrate 11 is greater than 3000 Ω•cm. This design can avoid low-frequency interference introduced by substrate leakage.
[0029] The dielectric constant of the oxide insulating buried layer 12 is 4.1. This design can reduce the effects of low-frequency parasitics.
[0030] The first metal layer 13 is made of Cu, the second metal layer 14 is made of Cu, and the third metal layer 15 is made of Al. This design can reduce the resistance of ultra-low frequency technology.
[0031] The high-resistivity silicon substrate 11 has a thickness of 300±10μm, the oxide insulating buried layer 12 has a thickness of 0.47μm, the first metal layer 13 has a thickness of 0.29±0.05μm, the second metal layer 14 has a thickness of 0.32±0.05μm, and the third metal layer 15 has a thickness of 4±0.05μm. This design minimizes the thickness of the coupler 100 without affecting its performance.
[0032] The second metal layer 14 is provided with a plurality of first metal vias 141 that extend through it and are spaced apart from each other along the stacking direction of the substrate 1, and the first metal layer 13 is provided with second metal vias 131 that extend through it and are spaced apart from each other along the stacking direction of the substrate 1. The third metal layer 15 is electrically connected to the second metal layer 14 through the first metal vias 141, and the second metal layer 14 is electrically connected to the first metal layer 13 through the second metal vias 131.
[0033] The input waveguide 151, coupling waveguide 152, isolation waveguide 153 and output port line 154 are spaced apart and formed on the third metal layer 15, while the jump waveguide 142 and transition waveguide 143 are spaced apart and formed on the second metal layer 14.
[0034] By placing the input waveguide 151 and the coupling waveguide 152 on the top third metal layer 15, the coupling degree of the low-frequency signal and the low loss of the corresponding waveguide can be guaranteed.
[0035] The width of the input waveguide 151 and the width of the jumper waveguide 142 are the same, both being 40±5μm. This design ensures that the transmission loss of the input waveguide 151 and the jumper waveguide 142 is sufficiently low to accommodate ultra-low frequency high current distributions.
[0036] The coupling waveguide 152 and the isolation waveguide 153 have the same width, both being 10±5μm. This design ensures the range of the coupling coefficient, achieving high-precision signal coupling.
[0037] The input waveguide 151 is wound 1.5 turns, the coupling waveguide 152 starts from one side of the input waveguide 151 and is wound 2.5 turns along the input waveguide 151, the isolation waveguide 153 is disposed on the other side of the input waveguide 151, the output port line 154 and the coupling waveguide 152 are located on the same side of the input waveguide 151, and the output port line 154 is further away from the input waveguide 151 than the coupling waveguide 152.
[0038] The spacing between the coupling waveguide 152 and the input waveguide 151 is less than 6 μm, and the spacing between the isolation waveguide 153 and the input waveguide 151 is less than 6 μm. This design allows for minimizing the size of the coupler 100 without affecting its performance.
[0039] The first portion of the coupling waveguide 152 is coupled to the input waveguide 151, and the orthographic projection of the first portion of the coupling waveguide 152 along the stacking direction perpendicular to the substrate 1 completely falls into the input waveguide 151. The first portion of the isolation waveguide 153 is coupled to the input waveguide 151, and the orthographic projection of the first portion of the isolation waveguide 153 along the stacking direction perpendicular to the substrate 1 completely falls into the portion of the input waveguide 151. This design forms the coupling region of the coupler 100.
[0040] The length of the metal region formed by the input waveguide 151, coupling waveguide 152, and isolation waveguide 153 is 300 μm, and the width of the metal region formed by the input waveguide 151, coupling waveguide 152, and isolation waveguide 153 is 200 μm. This design allows for minimizing the size of the coupler 100 without affecting its performance.
[0041] The sum of the area of the portion of the coupling waveguide 152 projected perpendicularly to the stacking direction of the substrate 1 and falling into the input waveguide 151, and the area of the portion of the isolation waveguide 153 projected perpendicularly to the stacking direction of the substrate 1 and falling into the input waveguide 151, is 4-6% of the area of the metal region composed of the input waveguide 151, the coupling waveguide 152, and the isolation waveguide 153.
[0042] The outer end of the input waveguide 151 serves as the input terminal P1 of the coupler 100, the outer end of the coupling waveguide 152 serves as the coupling terminal P3 of the coupler 100, one end of the isolation waveguide 153 serves as the isolation terminal P4 of the coupler 100, and the output port line 154 serves as the output terminal P2 of the coupler 100.
[0043] The input terminal P1 of coupler 100 is used to connect to the output terminal of the power amplifier, the coupling terminal P3 of coupler 100 is used to connect to the monitoring circuit, the isolation terminal P4 of coupler 100 is used to connect to the adjustable matching circuit, and its matching impedance can be dynamically adjusted according to the operating frequency band, and the output terminal P2 of coupler 100 is used to connect to the RF main link.
[0044] The two ends of the jumper waveguide 142 are connected to the inner end of the input waveguide 151 and the output port line 154 through two first metal through holes 141, respectively. This design ensures smooth connection between the input and output of the radio frequency signal.
[0045] The jumper waveguide 142 is provided with a plurality of through holes 1421 that extend through it along the stacking direction of the substrate 1 and are spaced apart from each other. Each through hole 1421 extends along the output port line 154 near the inner end of the input waveguide 151. The spacing between two adjacent through holes 1421 is less than 8 μm, and the width of each through hole 1421 perpendicular to its extension direction is 10 ± 1 μm. This design can improve the isolation of the coupler 100 and the loss of the path.
[0046] The two ends of the adapter waveguide 143 are connected to the inner end of the coupling waveguide 152 and the other end of the isolation waveguide 153 through two first metal through holes 141, respectively. This design ensures that the coupling degree of the coupler 100 is sufficiently large.
[0047] The orthographic projection of the transition waveguide 143 along the stacking direction of the substrate 1 overlaps with the coupling waveguide 152; the area of the overlapping portion of the orthographic projection of the transition waveguide 143 along the stacking direction of the substrate 1 and the coupling waveguide 152 is 1500 μm. 2 -2000μm 2 This design can improve the isolation and coupling accuracy of the coupler 100, with the coupling accuracy improved by about 1%.
[0048] In this embodiment, the coupler 100 forms a waveguide metal-ultra-thick buried oxide layer-ultra-high resistivity silicon substrate structure.
[0049] The insertion loss curves of the coupler 100 in this embodiment at different frequency bands are as follows: Figure 4 As shown, the coupling accuracy of the coupler 100 in this embodiment at a frequency of 915MHz is curves for different phases when the antenna voltage standing wave ratio (VSWR) is 5:1. Figure 5 As shown.
[0050] Compared with related technologies, the coupler 100 of the present invention, by designing a substrate 1, an input waveguide 151, a jumper waveguide 142, a coupling waveguide 152, an isolation waveguide 153, a transition waveguide 143 and an output port line 154 formed on the substrate 1, and defining each structure, can achieve low parasitics, high narrowband, stable sampling and low power consumption of the coupler 100.
[0051] Compared with related technologies, the coupler 100 of this embodiment designs a substrate 1, an input waveguide 151, a jumper waveguide 142, a coupling waveguide 152, an isolation waveguide 153, a transition waveguide 143, and an output port line 154 formed on the substrate 1. The coupling waveguide 152 starts from one side of the input waveguide 151 and wraps around the input waveguide 151 2.5 times. The first part of the coupling waveguide 152 is coupled to the input waveguide 151, and the first part of the isolation waveguide 153 is coupled to the input waveguide 151. Multiple through holes 1421 are provided on the jumper waveguide 142, so that the orthographic projection of the transition waveguide 143 along the stacking direction of the substrate 1 overlaps with the coupling waveguide 152, thereby enabling… This design achieves low parasitics, high narrowband performance, stable sampling, and low power consumption in the coupler 100. In this embodiment, the insertion loss of the coupler 100 is reduced to within 0.1 dB, and the coupling accuracy reaches within ±0.5 dB, effectively ensuring monitoring accuracy and main signal quality. The overall size can be controlled within 300 μm, allowing direct integration into RF front-end modules to meet the needs of small electronic devices such as mobile phones. Through the design of an adjustable matching circuit, no additional special processes are required, improving module communication stability and battery life while controlling mass production costs. It can provide real-time and accurate status monitoring data for the power amplifier, facilitating dynamic bias adjustment and harmonic suppression optimization, ensuring the power amplifier maintains optimal operating conditions in each sub-frequency band.
[0052] Example 2 This embodiment provides a radio frequency front-end module 200, combined with... Figure 6 As shown, it includes the coupler 100 in Embodiment 1, the power amplifier 201 formed on the substrate 1, the frequency band selection switch 202, the frequency band filter 203, the antenna switch 204, the first capacitor C1, the first resistor R1, the monitoring circuit 205, the isolation matching circuit 206, the inductor L, and the antenna 207.
[0053] The input terminal of power amplifier 201 is used to receive radio frequency signals.
[0054] The first terminal of the frequency band selection switch 202 is connected to the output terminal of the power amplifier 201 and is used to select the frequency band signal to pass.
[0055] The input terminal of the frequency band filter 203 is connected to the second terminal of the frequency band selection switch 202 and is used to filter the received frequency band signal.
[0056] The input terminal of antenna switch 204 is connected to the output terminal of band filter 203 and is used to select the frequency band signal to pass.
[0057] The input terminal P1 of coupler 100 is connected to the output terminal of antenna switch 204.
[0058] The first terminal of the first capacitor C1 is connected to the coupling terminal P3 of the coupler 100.
[0059] The first end of the first resistor R1 is connected to the second end of the first capacitor C1, and the second end of the first resistor R1 is grounded.
[0060] The input terminal of the monitoring circuit 205 is connected to the second terminal of the first capacitor C1, and the output terminal of the monitoring circuit 205 is used to output the voltage monitoring signal Vdet.
[0061] The isolation matching circuit 206 includes multiple second resistors R2 and multiple second capacitors C2 in the same number as the second resistors R2; the first ends of the multiple second resistors R2 and the first ends of the multiple second capacitors C2 are respectively connected to the isolation terminal P4 of the coupler 100, and the second ends of the multiple second resistors R2 and the second ends of the multiple second capacitors C2 are connected and grounded together; the impedance of the isolation matching circuit 206 can be adjusted.
[0062] The first end of inductor L is connected to the output terminal P2 of coupler 100, and the second end of inductor L is grounded. The input terminal of antenna 207 is connected to the output terminal P2 of coupler 100. Antenna 207 is used to output or receive radio frequency signals.
[0063] In this embodiment, the radio frequency signal output by the power amplifier 201 enters the input waveguide 151 through the input terminal P1 of the coupler 100. Energy transfer is achieved through the input waveguide 151, and part of the signal is coupled to the isolation waveguide 153 to form a monitoring signal. This signal is then transmitted to the monitoring circuit 205 through the coupling terminal P3 of the coupler 100. The main signal is then transmitted to the subsequent filter and antenna 207 through the output terminal P2 of the coupler 100. In this embodiment, the coupler 100 is in bidirectional coupling monitoring mode. The signal reflected or received by the antenna 207 can be transmitted to the monitoring circuit 205 through the isolation terminal P4 of the coupler 100.
[0064] In this embodiment, the internal controller adjusts the impedance value of the adjustable isolation matching circuit 206 of the isolation terminal P4 of the coupler 100 according to the operating frequency band selected by the antenna switch 204 unit, which can optimize the signal isolation effect under different sub-frequency bands and improve the adaptability of the entire frequency band.
[0065] In this embodiment, the coupler 100 and the transmit / receive switching module are integrated into the same SOI chip and connected to the output terminal of the power amplifier 201 of the Sub-3G LB through the traces of the substrate 1. The transmit link module is integrated, the output terminal P2 of the coupler 100 is connected to the output matching circuit, and the coupling terminal is connected to the signal processing chip of the monitoring circuit 205 through the signal transmission line to form a complete transmit and monitoring link.
[0066] In this embodiment, the RF signal amplified by the power amplifier 201 enters the coupler 100 via the transmission link and is divided into a main signal and a monitoring signal. The monitoring circuit 205 analyzes the coupled signal for parameters such as power and linearity, and generates a control signal that is fed back to the bias circuit of the power amplifier 201. The internal controller synchronously adjusts the matching impedance of the isolation terminal P4 of the coupler 100 and the operating parameters of the power amplifier 201 according to the operating frequency band to achieve closed-loop optimization.
[0067] In this embodiment, the coupler 100 is fabricated using SOI lithography and etching processes, and is packaged together with the power amplifier 201 and other components in the RF front-end module 200 to reduce losses and space occupation.
[0068] The curves of coupling coefficient, directivity, and isolation of the coupler 100 in the RF front-end module 200 in this embodiment are as follows: Figure 7 As shown.
[0069] Since the RF front-end module 200 in this embodiment uses the coupler 100 in Embodiment 1, it can achieve the same technical effect as the coupler 100 in Embodiment 1, which will not be elaborated here.
[0070] It should be noted that the various embodiments described above with reference to the accompanying drawings are merely illustrative of the present invention and not intended to limit its scope. Those skilled in the art should understand that any modifications or equivalent substitutions made to the present invention without departing from its spirit and scope should be included within the scope of the present invention. Furthermore, unless the context otherwise requires, words appearing in the singular include those in the plural, and vice versa. Additionally, unless specifically stated otherwise, all or part of any embodiment may be used in conjunction with all or part of any other embodiment.
Claims
1. A coupler, characterized in that, The coupler includes a substrate and an input waveguide, a jumper waveguide, a coupling waveguide, an isolation waveguide, a transition waveguide, and an output port line, which are respectively formed on the substrate. The substrate is formed by stacking multiple layers, including a high-resistivity silicon substrate, an oxide insulating buried layer, a first metal layer, a second metal layer and a third metal layer stacked sequentially; the second metal layer is provided with a plurality of first metal vias that penetrate through it along the stacking direction of the substrate and are spaced apart from each other; the resistivity of the high-resistivity silicon substrate is greater than 3000 Ω•cm. The input waveguide, the coupling waveguide, the isolation waveguide, and the output port line are spaced apart from each other and formed on the third metal layer, while the jump waveguide and the transition waveguide are spaced apart from each other and formed on the second metal layer. The input waveguide is wound 1.5 times, the coupling waveguide starts from one side of the input waveguide and wound 2.5 times, the isolation waveguide is disposed on the other side of the input waveguide, the output port line and the coupling waveguide are located on the same side of the input waveguide, and the output port line is further away from the input waveguide relative to the coupling waveguide; the first portion of the coupling waveguide is coupled to the input waveguide, and the orthographic projection of the first portion of the coupling waveguide perpendicular to the stacking direction of the substrate completely falls into the input waveguide; the first portion of the isolation waveguide is coupled to the input waveguide, and the orthographic projection of the first portion of the isolation waveguide perpendicular to the stacking direction of the substrate completely falls into the input waveguide; The outer end of the input waveguide serves as the input end of the coupler, the outer end of the coupling waveguide serves as the coupling end of the coupler, one end of the isolation waveguide serves as the isolation end of the coupler, and the output port line serves as the output end of the coupler. The two ends of the jump waveguide are respectively connected to the inner end of the input waveguide and the output port line through two first metal through holes; the jump waveguide is provided with a plurality of through holes that pass through it along the stacking direction of the substrate and are spaced apart from each other, and each through hole extends along the direction of the output port line near the inner end of the input waveguide. The two ends of the transition waveguide are respectively connected to the inner end of the coupling waveguide and the other end of the isolation waveguide through two first metal through holes, and the orthogonal projection portion of the transition waveguide along the stacking direction of the substrate overlaps with the coupling waveguide.
2. The coupler as described in claim 1, characterized in that, The thickness of the high-resistivity silicon substrate is 300±10μm; the thickness of the oxide insulating buried layer is 0.47μm, and the dielectric constant of the oxide insulating buried layer is 4.
1.
3. The coupler as described in claim 1, characterized in that, The first metal layer is made of Cu and has a thickness of 0.29±0.05μm; the second metal layer is made of Cu and has a thickness of 0.32±0.05μm; the third metal layer is made of Al and has a thickness of 4±0.05μm.
4. The coupler as described in claim 3, characterized in that, The width of the input waveguide and the width of the jump waveguide are the same, both being 40±5μm; the width of the coupling waveguide and the isolation waveguide are the same, both being 10±5μm.
5. The coupler as described in claim 4, characterized in that, The area of the overlap between the orthographic projection of the transition waveguide along the stacking direction of the substrate and the coupling waveguide is 1500 μm. 2 -2000μm 2 .
6. The coupler as described in claim 5, characterized in that, The distance between two adjacent perforations is less than 8 μm, and the width of each perforation along its extension direction is 10 ± 1 μm.
7. The coupler as claimed in claim 6, characterized in that, The distance between the coupling waveguide and the input waveguide is less than 6 μm, and the distance between the isolation waveguide and the input waveguide is less than 6 μm.
8. The coupler as claimed in claim 1, characterized in that, The sum of the area of the portion of the coupling waveguide projected perpendicularly to the stacking direction of the substrate and falling into the input waveguide, and the area of the portion of the isolation waveguide projected perpendicularly to the stacking direction of the substrate and falling into the input waveguide, is 4-6% of the area of the metal region composed of the input waveguide, the coupling waveguide, and the isolation waveguide.
9. A radio frequency front-end module, characterized in that, The radio frequency front-end module includes a coupler as described in any one of claims 1 to 8, a power amplifier formed on the substrate, a band selection switch, a band filter, an antenna switch, a first capacitor, a first resistor, a monitoring circuit, an isolation matching circuit, an inductor, and an antenna; The input terminal of the power amplifier is used to receive radio frequency signals; The first terminal of the frequency band selection switch is connected to the output terminal of the power amplifier and is used to select the frequency band signal to pass. The input terminal of the frequency band filter is connected to the second terminal of the frequency band selection switch and is used to filter the received frequency band signal. The input terminal of the antenna switch is connected to the output terminal of the frequency band filter and is used to select the frequency band signal to pass. The input terminal of the coupler is connected to the output terminal of the antenna switch; The first terminal of the first capacitor is connected to the coupling terminal of the coupler; The first end of the first resistor is connected to the second end of the first capacitor, and the second end of the first resistor is grounded. The input terminal of the monitoring circuit is connected to the second terminal of the first capacitor, and the output terminal of the monitoring circuit is used to output a voltage monitoring signal. The isolation matching circuit includes a plurality of second resistors and a number of second capacitors equal to the number of the second resistors; The first ends of the plurality of second resistors and the first ends of the plurality of second capacitors are respectively connected to the isolation terminals of the coupler, and the second ends of the plurality of second resistors and the second ends of the plurality of second capacitors are connected together and grounded. The first end of the inductor is connected to the output end of the coupler, and the second end of the inductor is grounded; The input terminal of the antenna is connected to the output terminal of the coupler, and the antenna is used to output or receive radio frequency signals.