WO2024067211A1 - 射频前端电路和电子设备 - Google Patents

射频前端电路和电子设备 Download PDF

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Publication number
WO2024067211A1
WO2024067211A1 PCT/CN2023/119424 CN2023119424W WO2024067211A1 WO 2024067211 A1 WO2024067211 A1 WO 2024067211A1 CN 2023119424 W CN2023119424 W CN 2023119424W WO 2024067211 A1 WO2024067211 A1 WO 2024067211A1
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WIPO (PCT)
Prior art keywords
port
conversion unit
coupling member
phase conversion
electrically connected
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Application number
PCT/CN2023/119424
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English (en)
French (fr)
Inventor
万顺
孟繁荣
Original Assignee
华为技术有限公司
清华大学
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Application filed by 华为技术有限公司, 清华大学 filed Critical 华为技术有限公司
Publication of WO2024067211A1 publication Critical patent/WO2024067211A1/zh

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits

Definitions

  • the present application relates to the field of electronics, and in particular to a radio frequency front-end circuit and electronic equipment.
  • Electromagnetic waves with frequencies below 100kHz will be absorbed by the surface and cannot form effective transmission. Electromagnetic waves with frequencies above 100kHz can propagate in the air and be reflected by the ionosphere at the outer edge of the atmosphere, forming long-distance transmission capabilities. This high-frequency electromagnetic wave with long-distance transmission capabilities can be called radio frequency. In electronic devices, the frequency of the transmitted electrical signals is relatively low, with a maximum of only a few hundred kHz, such as voice signals.
  • the radio frequency module in the electronic device needs to modulate the electrical signals from low frequency to a specified high-frequency band, such as the 900MHz global system for mobile communications (GSM) communication technology band, the 1.9GHz long-term evolution (LTE) communication technology band, and the 3.5GHz fifth generation (5G) mobile communication system band.
  • GSM global system for mobile communications
  • LTE long-term evolution
  • 5G fifth generation
  • the PA designed based on the Doherty architecture has the advantages of low power consumption, high efficiency, and good linearity, and is used in RF modules.
  • a 90° phase conversion unit is introduced after the main PA, resulting in limited broadband performance.
  • a 180° phase conversion unit is introduced after the original peak PA to expand the working bandwidth, but the volume of the half impedance conversion unit is too large, and it is difficult to implement on a carrier board or chip.
  • the present application provides a radio frequency front-end circuit and an electronic device.
  • the radio frequency front-end circuit has a wider operating bandwidth and occupies a smaller area.
  • a radio frequency front-end circuit comprising: a power divider, a first power amplifier PA, a second PA, a phase compensation unit, a 90° phase conversion unit and a 180° phase conversion unit; wherein the common port of the power divider is electrically connected to the input port of the radio frequency front-end circuit; the phase compensation unit is connected in series between the first port of the power divider and the first port of the first PA; the 90° phase conversion unit is connected in series between the second port of the first PA and a combining point; the second PA is connected in series between the second port of the power divider and the first port of the 180° phase conversion unit; the second port of the 180° phase conversion unit is electrically connected to the combining point; and the 180° phase conversion unit is a coupling transformer.
  • the RF signal is input from the common port of the power divider and is divided into two RF signals (a first RF signal and a second RF signal) through the power divider.
  • the first RF signal is phase-inverted (the phase of the RF signal is changed) through the phase compensation unit, and then the first RF signal is power amplified by the first PA.
  • the first RF signal after power amplification is transmitted to the 90° phase conversion unit for impedance conversion.
  • the second RF signal is power amplified through the second PA, and the second RF signal after power amplification is transmitted to the 180° phase conversion unit for phase conversion.
  • the first RF signal after phase conversion and the second RF signal after impedance conversion are combined into a third RF signal at the combining point.
  • the third port and the fourth port of the 180° phase conversion unit are grounded.
  • the 180° phase conversion unit includes a first coupling member and a second coupling member arranged opposite to each other; a first end of the first coupling member and a first end of the second coupling member are located on a first side, and a second end of the first coupling member and a second end of the second coupling member are located on a second side; a first end of the first coupling member is electrically connected to a first port of the 180° phase conversion unit, and a second end of the first coupling member is electrically connected to a third port of the 180° phase conversion unit; The first end of the coupling element is electrically connected to the fourth port of the 180° phase conversion unit, and the second end of the second coupling element is electrically connected to the second port of the 180° phase conversion unit.
  • the 180° phase conversion unit can realize the phase conversion of the input RF signal through the indirect coupling of the first coupling member and the second coupling member. Since the component occupies a smaller area than the structure of the above-mentioned microstrip line or circuit network, it can be applied to chips or electronic devices.
  • the first coupling member and the second coupling member are metal wires.
  • the metal wire can be straight or zigzag, which can be determined according to the actual layout.
  • a length of the first coupling member is different from a length of the second coupling member.
  • the length and width of the first coupling member or the second coupling member are related to the phase transformation of the radio frequency signal through the 180° phase transformation unit.
  • the phase of the radio frequency signal after passing through the 180° phase transformation unit can be controlled by adjusting the length and width of the first coupling member or the second coupling member.
  • the RF front-end circuit also includes a RF chip; the RF chip includes an output port; and the output port is electrically connected to a common port of the power divider.
  • the RF front-end circuit also includes a filter; and the filter is electrically connected to the combining point.
  • an electronic device comprising: a power divider, a first power amplifier PA, a second PA, a phase compensation unit, a 90° phase conversion unit and a 180° phase conversion unit; wherein the common port of the power divider is electrically connected to the input port of the RF front-end circuit; the phase compensation unit is connected in series between the first port of the power divider and the first port of the first PA; the 90° phase conversion unit is connected in series between the second port of the first PA and a combining point; the second PA is connected in series between the second port of the power divider and the first port of the 180° phase conversion unit; the second port of the 180° phase conversion unit is electrically connected to the combining point; and the 180° phase conversion unit is a coupling transformer.
  • the third port and the fourth port of the 180° phase conversion unit are grounded.
  • the 180° phase conversion unit includes a first coupling member and a second coupling member arranged opposite to each other; the first end of the first coupling member and the first end of the second coupling member are located on the first side, and the second end of the first coupling member and the second end of the second coupling member are located on the second side; the first end of the first coupling member is electrically connected to the first port of the 180° phase conversion unit, and the second end of the first coupling member is electrically connected to the third port of the 180° phase conversion unit; the first end of the second coupling member is electrically connected to the fourth port of the 180° phase conversion unit, and the second end of the second coupling member is electrically connected to the second port of the 180° phase conversion unit.
  • the first coupling member and the second coupling member are metal wires.
  • a length of the first coupling member is different from a length of the second coupling member.
  • the electronic device further includes a radio frequency chip; the radio frequency chip includes an output port; and the output port is electrically connected to a common port of the power divider.
  • the electronic device further includes an antenna module; and the combining point is electrically connected to the antenna module.
  • the RF front-end circuit also includes a filter; the filter is connected in series between the antenna module and the combining point.
  • FIG. 1 is a schematic diagram of an electronic device provided in an embodiment of the present application.
  • FIG. 2 is a schematic diagram of an internal circuit of an electronic device provided in an embodiment of the present application.
  • FIG3 is a schematic diagram of a radio frequency front-end circuit provided in an embodiment of the present application.
  • FIG4 is a schematic diagram of a radio frequency front-end circuit provided in an embodiment of the present application.
  • FIG5 is a radio frequency front-end circuit designed based on a Doherty architecture provided in an embodiment of the present application.
  • FIG6 is a radio frequency front-end circuit of an inverted Doherty architecture design provided in an embodiment of the present application.
  • FIG. 7 is a gain compression curve of the RF front-end circuit shown in FIG. 6 .
  • FIG8 is a power added efficiency curve of the RF front-end circuit shown in FIG6 .
  • FIG. 9 is a two-stage capacitor-inductor-capacitor network provided in an embodiment of the present application.
  • FIG. 10 is a simulation result of the phase of the circuit network shown in FIG. 9 .
  • FIG. 11 is a schematic diagram of a radio frequency front-end circuit 100 provided in an embodiment of the present application.
  • FIG. 12 is a schematic diagram of a 180° phase conversion unit provided in an embodiment of the present application.
  • FIG. 13 is a schematic diagram of the structure of a 180° phase conversion unit provided in an embodiment of the present application.
  • FIG. 14 is a circuit connection diagram of the PA provided in an embodiment of the present application.
  • FIG. 15 is a simulation result of the phase of the 180° phase conversion unit 142 .
  • FIG. 16 is a simulation result of the Q value of the 180° phase conversion unit 142 .
  • FIG. 17 is a gain compression curve of the RF front-end circuit 100 shown in FIG. 11 .
  • FIG. 18 is a power added efficiency curve of the RF front-end circuit 100 shown in FIG. 11 .
  • the electronic device 10 may include: a cover 13, a display screen/module (display) 15, a printed circuit board (PCB) 17, a middle frame (middle frame) 19 and a rear cover (rear cover) 21.
  • the cover 13 may be a glass cover, or may be replaced by a cover made of other materials, such as an ultra-thin glass material cover, a PET (Polyethylene terephthalate) material cover, etc.
  • the cover plate 13 may be disposed closely to the display module 15 , and may be mainly used to protect the display module 15 and prevent dust.
  • the display module 15 may include a liquid crystal display panel (LCD), a light emitting diode (LED) display panel or an organic light-emitting semiconductor (OLED) display panel, etc., but the embodiments of the present application do not limit this.
  • LCD liquid crystal display panel
  • LED light emitting diode
  • OLED organic light-emitting semiconductor
  • the middle frame 19 mainly supports the whole machine.
  • FIG. 1 shows that the PCB 17 is arranged between the middle frame 19 and the back cover 21.
  • the PCB 17 can also be arranged between the middle frame 19 and the display module 15, and the embodiment of the present application does not limit this.
  • the printed circuit board PCB17 can adopt a flame retardant material (FR-4) dielectric board, or a Rogers dielectric board, or a mixed dielectric board of Rogers and FR-4, and so on.
  • FR-4 is a code for a grade of flame retardant material
  • the Rogers dielectric board is a high-frequency board.
  • Electronic components, such as radio frequency chips, are carried on the PCB 17.
  • a metal layer can be provided on the printed circuit board PCB17.
  • the metal layer can be used for grounding the electronic components carried on the printed circuit board PCB17, and can also be used for grounding other components, such as bracket antennas, frame antennas, etc.
  • the metal layer can be called a floor, or a grounding plate, or a grounding layer.
  • the metal layer can be formed by etching metal on the surface of any layer of the dielectric board in the PCB 17.
  • the metal layer for grounding can be arranged on one side of the printed circuit board PCB17 close to the middle frame 19.
  • the edge of the printed circuit board PCB17 can be regarded as the edge of its grounding layer.
  • the metal middle frame 19 can also be used for grounding the above-mentioned components.
  • the electronic device 10 can also have other floors/grounding plates/grounding layers, as described above, which will not be repeated here.
  • the electronic device 10 may further include a battery (not shown).
  • the battery may be disposed between the middle frame 19 and the back cover 21, or between the middle frame 19 and the display module 15, and the embodiment of the present application does not limit this.
  • the PCB 17 is divided into a main board and a sub-board, and the battery may be disposed between the main board and the sub-board, wherein the main board may be disposed between the middle frame 19 and the upper edge of the battery, and the sub-board may be disposed between the middle frame 19 and the lower edge of the battery.
  • the electronic device 10 may further include a frame 11, which may be formed of a conductive material such as metal.
  • the frame 11 may be disposed between the display module 15 and the back cover 21 and extend circumferentially around the periphery of the electronic device 10.
  • the frame 11 may have four sides surrounding the display module 15 to help fix the display module 15.
  • the frame 11 made of a metal material may be directly used as a metal frame of the electronic device 10, forming the appearance of a metal frame, which is suitable for a metal industrial design (ID).
  • ID metal industrial design
  • the outer surface of the frame 11 may also be a non-metallic material, such as a plastic frame, forming the appearance of a non-metallic frame, which is suitable for a non-metallic ID.
  • the middle frame 19 may include a border 11.
  • the middle frame 19 including the border 11 is an integral part and may support the electronic devices in the whole machine.
  • the cover 13 and the back cover 21 are respectively covered along the upper and lower edges of the border to form a shell or housing of the electronic device.
  • the cover 13, the back cover 21, the border 11 and/or the middle frame 19 may be collectively referred to as a shell or housing of the electronic device 10.
  • the term "shell or housing" may be used to refer to part or all of any one of the cover 13, the back cover 21, the border 11 or the middle frame 19, or
  • the frame 11 on the middle frame 19 can at least partially serve as an antenna radiator to receive/transmit radio frequency signals. There can be a gap between this portion of the frame serving as the radiator and other portions of the middle frame 19, thereby ensuring that the antenna radiator has a good radiation environment.
  • the middle frame 19 can be provided with an aperture at this portion of the frame serving as the radiator to facilitate the radiation of the antenna.
  • the frame 11 may not be considered as a part of the middle frame 19.
  • the frame 11 may be connected to the middle frame 19 and formed integrally.
  • the frame 11 may include a protrusion extending inward to be connected to the middle frame 19, for example, by means of a shrapnel, a screw, welding, etc.
  • the protrusion of the frame 11 may also be used to receive a feed signal, so that at least a portion of the frame 11 serves as a radiator of the antenna to receive/transmit radio frequency signals.
  • the back cover 21 may be a back cover made of metal material; it may also be a back cover made of non-conductive material, such as a glass back cover, a plastic back cover or other non-metallic back cover; it may also be a back cover made of both conductive material and non-conductive material.
  • the antenna of the electronic device 10 can also be arranged in the frame 11.
  • the antenna radiator can be located in the electronic device 10 and arranged along the frame 11.
  • the antenna radiator is arranged close to the frame 11 to minimize the volume occupied by the antenna radiator and to be closer to the outside of the electronic device 10 to achieve better signal transmission effect.
  • the antenna radiator is arranged close to the frame 11 means that the antenna radiator can be arranged close to the frame 11, or it can be arranged close to the frame 11, for example, there can be a certain small gap between the antenna radiator and the frame 11.
  • the antenna of the electronic device 10 can also be arranged in the housing, such as a bracket antenna, a millimeter wave antenna, etc. (not shown in FIG. 1 ).
  • the clearance of the antenna arranged in the housing can be obtained by the slits/openings on any one of the middle frame, and/or the frame, and/or the back cover, and/or the display screen, or by the non-conductive gap/aperture formed between any of them.
  • the clearance setting of the antenna can ensure the radiation performance of the antenna. It should be understood that the clearance of the antenna can be a non-conductive area formed by any conductive component in the electronic device 10, and the antenna radiates signals to the external space through the non-conductive area.
  • the antenna 40 can be in the form of an antenna based on a flexible printed circuit (FPC), an antenna based on laser direct structuring (LDS), or a microstrip disk antenna (MDA).
  • the antenna can also adopt a transparent structure embedded in the screen of the electronic device 10, so that the antenna is a transparent antenna unit embedded in the screen of the electronic device 10.
  • FIG. 1 only schematically shows some components included in the electronic device 10 , and the actual shapes, sizes and structures of these components are not limited by FIG. 1 .
  • the surface where the display screen of the electronic device is located can be considered as the front side
  • the surface where the back cover is located can be considered as the back side
  • the surface where the frame is located can be considered as the side side
  • the electronic device when a user holds the electronic device (usually vertically and facing the screen), the electronic device is located with a top, a bottom, a left side, and a right side.
  • FIG. 2 is a schematic diagram of an internal circuit of an electronic device provided in an embodiment of the present application.
  • the electronic device may include an application processor (AP), a baseband module, a digital-to-analog converter, a radio frequency module and an antenna module.
  • AP application processor
  • baseband module a digital-to-analog converter
  • radio frequency module a radio frequency module
  • antenna module an antenna module
  • the application processor can be used to run an open operating system and various applications on the operating system, and is responsible for the control of the entire system. In the process of transmitting signals to the outside, the application processor can transmit digital signals, such as voice signals, to the baseband module.
  • the baseband module can be used to encode and modulate the received digital signal. For example, in the process of transmitting an electrical signal to the outside, the baseband module encodes and modulates it to make the space occupied by the information in the digital signal smaller, and can resist interference and attenuation in the channel and improve link performance.
  • the digital-to-analog converter can be used to convert the digital signal output by the baseband module into an analog signal for processing by the RF module.
  • the analog signal output by the RF module can be converted into a digital signal for processing by the baseband module.
  • the RF module can be used to modulate the frequency of the received electrical signal and amplify the power. For example, in the process of transmitting an electrical signal to the outside, the RF module modulates the analog signal from a low frequency to a specified high frequency band to become a RF signal that can be transmitted in the air, and amplifies the power of the RF signal to meet the communication requirements.
  • the antenna module can be used to transmit the radio frequency signal processed by the radio frequency module to the outside, or to receive the external electromagnetic wave signal and transmit it to the radio frequency module.
  • the radio frequency front-end circuit may be the portion of the radio frequency module shown in FIG. 2 that is close to the antenna module.
  • the RF front-end circuit may include a RF chip (RF IC) and a RF front-end module (Front end module, FEM).
  • RF IC RF chip
  • FEM Front end module
  • the RF chip can be used to modulate and demodulate the RF signal, and can up-convert (increase the frequency of the RF signal) and down-convert (reduce the frequency of the RF signal) the RF signal.
  • the PA can be set on the transmit channel to amplify the power of the transmitted RF signal.
  • the LNA can be set on the receive channel to amplify the power of the RF signal received by the antenna module.
  • the switch can be used to switch the RF channel (transmit channel or receive channel) connected to the antenna module in different time slots.
  • the RF front-end circuit can be made to work in a time division duplex (TDD) communication system.
  • TDD time division duplex
  • the switch is switched to the transmitting channel, so that the transmitting channel and the antenna module are electrically connected, and the RF signal is transmitted to the antenna module through the transmitting channel and radiated to the outside.
  • the switch is switched to the receiving channel, so that the receiving channel and the antenna module are electrically connected, and the RF signal received by the antenna module is transmitted to the RF chip through the receiving channel for processing.
  • the RF front-end circuit operates in a frequency division duplex (FDD) communication system.
  • the RF front-end circuit may also not include a switch, and the transmitting channel and the receiving channel are electrically connected to different antenna units in the antenna module, as shown in FIG4 .
  • FIG5 is a radio frequency front-end circuit designed based on a Doherty architecture provided in an embodiment of the present application.
  • the RF signal generated by the RF chip is divided into a first RF signal and a second RF signal via a power divider.
  • the first RF signal is power amplified via the main PA, and the phase of the first RF signal is changed by a 90° phase conversion unit to transform its impedance.
  • the second RF signal changes its phase via a phase compensation unit so that the second RF signal has the same phase as the first RF signal at the junction point, so as to synthesize the RF signals, and amplify the power of the second RF signal via a peak PA.
  • the first RF signal and the second RF signal are combined into a third RF signal at the junction point and transmitted to the antenna module.
  • phase conversion unit can be understood as an impedance conversion unit, which uses the phase change of the RF signal to achieve impedance conversion.
  • the 90° phase conversion unit can be understood as a quarter-wavelength impedance conversion unit
  • the 180° phase conversion unit can be understood as an inverting unit. After the RF signal passes through the 180° phase conversion unit, the phase is opposite (the phase difference is 180°).
  • the main PA may be a power amplifier in a class AB state, such as a carrier amplifier.
  • the peak PA may be a power amplifier in a class C state, such as a peak amplifier.
  • the PA circuit designed based on the Doherty architecture has the advantages of low power consumption and high efficiency.
  • FIG6 is a radio frequency front-end circuit of an inverted Doherty architecture design provided in an embodiment of the present application.
  • the RF circuit shown in Figure 6 introduces a 180° phase conversion unit after the peak PA (between the peak PA and the junction point).
  • the operating bandwidth of the RF front-end circuit can be expanded so that it can be applied to more communication frequency bands. Since the 180° phase conversion unit is introduced in the branch where the peak PA is located, in order to ensure that the RF signal amplified by the peak PA has the same phase as the RF signal passing through the main PA at the junction point, a phase compensation unit is introduced before the main PA (between the main PA and the power divider).
  • FIG. 7 and FIG. 8 are diagrams showing simulation results of the RF front-end circuit shown in FIG. 6 .
  • the gain fluctuation is within 1.2 dBm within the working frequency band (frequency points 1.8 GHz, 2.2 GHz and 2.6 GHz).
  • the efficiency fluctuation is within 5% within the working frequency band (frequency points 1.8 GHz, 2.2 GHz and 2.6 GHz).
  • the 180° phase conversion unit is usually implemented by a circuit formed by a microstrip line or a capacitor and inductor.
  • the width of the microstrip line needs to be 1.4mm.
  • the length of the microstrip line needs to be around 20mm to achieve a 180° phase conversion unit through a microstrip line. Regardless of the width or length of the microstrip line, this size level is unbearable at the chip level or on the substrate of an electronic device, and this solution is only suitable for scenarios such as base stations.
  • the circuit formed by capacitors and inductors When the circuit formed by capacitors and inductors is used as a 180° phase conversion unit, a larger parallel capacitor is required due to the low impedance of the PA output port. Taking the sub3G frequency band as an example, a single capacitor requires 15pF. If the inductor with this capacitance value is implemented on the chip substrate, the chip area required for a single capacitor is 17000um2 based on the capacitance density of the current mainstream process. For the inductor in the circuit, the inductance value is roughly 0.3nH, and due to the low quality factor (Q factor, Q) value on the chip substrate and problems such as through-current, the width of the inductor winding needs to be increased to more than 20um.
  • Q factor, Q quality factor
  • Q value is the main parameter to measure the inductor. It refers to the ratio of the inductive reactance to its equivalent loss resistance when the inductor works under an AC voltage of a certain frequency. The higher the Q value of the inductor, the smaller its loss and the higher its efficiency.
  • a two-order capacitor-inductor-capacitor network is required, with a total of four capacitors, as shown in (a) in Figure 9. Without considering factors such as avoidance, the area of the capacitor alone reaches 56,000um2.
  • a 180-degree phase shift unit formed by capacitors and inductors is shown in (b) in Figure 9, and its area reaches 482um ⁇ 301um.
  • the phase fluctuation of the network formed by the two-order capacitor-inductor-capacitor within the working frequency band is large, close to 100°, and the effect is poor, as shown in Figure 10. To reduce the phase fluctuation, more orders of networks need to be cascaded.
  • the capacitance value is large, it is also necessary to combine the specific process evaluation to determine whether the capacitor will bypass the RF signal. As a result, the capacitor with a larger capacitance value needs to be split, which increases the difficulty of layout and wiring, further increases the area of the unit, and introduces more parasitic parameters, increasing the difficulty of design.
  • An embodiment of the present application provides a radio frequency front-end circuit, which can be applied to the electronic device shown in FIG. 1 .
  • the radio frequency front-end circuit has a wider operating bandwidth and occupies a smaller area.
  • FIG11 is a schematic diagram of a radio frequency front-end circuit 100 provided in an embodiment of the present application, which can be applied to the electronic device shown in FIG1 .
  • the RF front-end circuit 100 may include a power divider 110 , a first PA 121 , a second PA 122 , a phase compensation unit 130 , a 90° phase conversion unit 141 , and a 180° phase conversion unit 142 .
  • the common port 111 of the power divider 110 is electrically connected to the input port of the RF front-end circuit 100.
  • the power divider 110 can be used to divide the RF signal transmitted to the common port 111 into a first RF signal 101 transmitted to the first port 112 and a second RF signal 102 transmitted to the second port 113.
  • the phase compensation unit 130 is connected in series between the first port 112 of the power divider 110 and the first port 1211 of the first PA 121.
  • the first port of the phase compensation unit 130 is electrically connected to the first port 112 of the power divider 110, and the second port of the phase compensation unit 130 is electrically connected to the first port 1211 of the first PA 121.
  • the phase compensation unit 130 can be used to implement phase inversion of the first RF signal 101.
  • the 90° phase conversion unit 141 is connected in series between the second port 1212 of the first PA 121 and the junction 150.
  • the first port of the 90° phase conversion unit 141 is electrically connected to the second port 1212 of the first PA 121, and the second port of the 90° phase conversion unit 141 is electrically connected to the junction 150.
  • the 90° phase conversion unit 141 can be used to change the phase of the first RF signal to perform impedance transformation.
  • the second PA 122 is connected in series between the second port 113 of the power divider 110 and the first port of the 180° phase conversion unit 142.
  • the first port 1221 of the second PA 122 is electrically connected to the second port 113 of the power divider 110, and the second port 1222 of the second PA 122 is electrically connected to the first port 1421 of the 180° phase conversion unit 142.
  • the 180° phase conversion unit 142 can be used to change the phase of the second RF signal so that the phase of the second RF signal is opposite (for example, the difference from the phase before the phase conversion is 180° ⁇ 10°).
  • the second port 1422 of the 180° phase conversion unit 142 is electrically connected to the junction 150.
  • the 180° phase conversion unit 142 is a coupling transformer.
  • the RF signal is input by the common port 111 of the power divider 110, and is divided into two RF signals (a first RF signal 101 and a second RF signal 102) via the power divider 110.
  • the first RF signal 101 is phase-inverted (the phase of the RF signal is changed) via the phase compensation unit 130, and then the first RF signal 101 is power amplified by the first PA 121.
  • the power-amplified first RF signal 101 is transmitted to the 90° phase conversion unit 141 for impedance conversion.
  • the second RF signal 102 is power-amplified via the second PA 122, and the power-amplified second RF signal 102 is transmitted to the 180° phase conversion unit 142 for phase conversion.
  • the first RF signal 101 after impedance conversion and the second RF signal 102 after phase conversion are synthesized into a third RF signal 103 at the combining point 150.
  • the combining point 150 may be electrically connected to the antenna module 200 , and the third RF signal 103 may be radiated outward through the antenna module 200 .
  • the first PA 121 may be a main PA under the Doherty architecture in the above embodiment.
  • the second PA 122 may be a peak PA under the Doherty architecture in the above embodiment.
  • the 180° phase conversion unit 142 may further include a third port 1423 and a fourth port 1424. 1423 and the fourth port 1424 can be electrically connected to the floor of the electronic device to achieve grounding.
  • the 180° phase conversion unit 142 may include a first coupling member 143 and a second coupling member 144, as shown in FIG12.
  • the first coupling member 143 and the second coupling member 144 may be arranged face to face.
  • the first end of the first coupling member 143 and the first end of the second coupling member 144 are located on the first side, and the second end of the first coupling member 143 and the second end of the second coupling member 144 are located on the second side.
  • the first end of the first coupling member 143 is electrically connected to the first port 1421 of the 180° phase conversion unit 142, and the second end of the first coupling member 143 is electrically connected to the third port 1423 of the 180° phase conversion unit 142.
  • the first end of the second coupling member 144 is electrically connected to the fourth port 1424 of the 180° phase conversion unit 142, and the second end of the second coupling member 144 is electrically connected to the second port 1422 of the 180° phase conversion unit 142.
  • the 180° phase conversion unit 142 can achieve phase conversion of the input RF signal through the indirect coupling of the first coupling member 143 and the second coupling member 144. Compared with the structure of the above-mentioned microstrip line or circuit network, the component occupies a smaller area and can be applied to the chip or the electronic device shown in Figure 1.
  • the 180° phase conversion unit 142 shown in FIG12 is a schematic diagram of the 180° phase conversion unit 142.
  • the 180° phase conversion unit 142 may be a structure as shown in FIG13, and the first coupling member 143 and the second metal coupling member 144 may be metal wires.
  • the metal wire may be in a straight line or a folded line shape, which may be determined according to the actual layout.
  • the 180° phase conversion unit 142 may be packaged or disposed on a chip or PCB substrate.
  • the first coupling member 143 and the second coupling member 144 are disposed on the substrate, the first end of the first coupling member 143 is the same as the first port 1421 of the 180° phase conversion unit 142, the second end of the first coupling member 143 is the same as the third port 1423 of the 180° phase conversion unit 142, the first end of the second coupling member 144 is the same as the fourth port 1424 of the 180° phase conversion unit 142, and the second end of the second coupling member 144 is the same as the second port 1422 of the 180° phase conversion unit 142.
  • the length of the first coupling member 143 may be the same as or different from the length of the second coupling member 144, or the width of the first coupling member 143 may be the same as or different from the width of the second coupling member 144.
  • the length and width of the first coupling member 143 or the second coupling member 144 are related to the phase transformation of the RF signal after passing through the 180° phase transformation unit 142.
  • the phase of the RF signal after passing through the 180° phase transformation unit 142 may be controlled by adjusting the length and width of the first coupling member 143 or the second coupling member 144.
  • the length of the first coupling element 143 or the second coupling element 144 may be less than or equal to 1500 um.
  • the length of the first coupling element 143 or the second coupling element 144 may be less than or equal to 900 um.
  • the width of the first coupling member 143 or the width of the second coupling member 144 may be less than or equal to 80 um.
  • the area occupied by the 180° phase conversion unit can be greatly reduced, so that it can be applied to chips or electronic devices.
  • the Q value of the 180° phase transformation unit 142 may be greater than or equal to 15, thereby reducing the loss of the RF signal transmitted in the 180° phase transformation unit 142 and improving the performance of the RF front-end circuit.
  • the arrangement of the first coupling member 143 or the second coupling member 144 can be adjusted according to layout requirements, for example, it can be in a zigzag shape, etc., and the present application does not impose any limitation on this.
  • the first PA 121 or the second PA 122 may further include a third port, a fourth port and a fifth port, as shown in Figure 14.
  • the third port and the fourth port may be electrically connected to a power source, and the fifth port may be used for grounding to enable the first PA 121 or the second PA 122 to work.
  • the RF front-end circuit 100 may further include a RF chip 160 .
  • the output port of the RF chip 160 may be electrically connected to the common port 111 of the power divider 110 , so as to transmit a RF signal to the power divider 110 .
  • the RF front-end circuit may further include a filter 170 .
  • the filter 170 may be connected in series between the combining point 150 and the antenna module 200 , and may be used to filter out clutter in the third RF signal 103 .
  • FIG15 and FIG16 are simulation results of the 180° phase conversion unit 142 in the RF front-end circuit 100 shown in FIG11.
  • FIG15 is a simulation result of the phase of the 180° phase conversion unit 142.
  • FIG16 is a simulation result of the Q value of the 180° phase conversion unit 142.
  • the phase fluctuation is only about 8°, which has good broadband characteristics and is superior to the microstrip line structure and capacitor-inductor-capacitor network.
  • the inverting unit implemented with this structure can make the broadband performance more convergent.
  • the Q value of the 180° phase conversion unit is greatly improved (the Q value of the winding inductor is only about 10), which can effectively reduce the loss of the RF signal and improve the performance of the RF front-end circuit.
  • Qs and Qp can be understood as the medium quality factor obtained by S wave and the quality factor obtained by P wave. The values of the two are different.
  • Figures 17 and 18 are simulation results of the RF front-end circuit 100 shown in Figure 11.
  • Figure 17 is a gain compression curve of the RF front-end circuit 100 shown in Figure 11.
  • Figure 18 is a power added efficiency curve of the RF front-end circuit 100 shown in Figure 11.
  • the gain fluctuation is within 1.2 dBm within the working frequency band (frequency points 1.8 GHz, 2.2 GHz and 2.6 GHz).
  • the efficiency fluctuation is within 5% within the working frequency band (frequency points 1.8 GHz, 2.2 GHz and 2.6 GHz).
  • the simulated gain compression curve and power added efficiency have good broadband consistency, and the saturation power is basically consistent.
  • the disclosed systems and devices can be implemented in other ways.
  • the device embodiments described above are only schematic.
  • the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.
  • Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the device or unit can be electrical or other forms.

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Abstract

本申请实施例提供了一种电学领域，尤其涉及一种射频前端电路和电子设备。射频前端电路包括功分器，第一PA，第二PA，相位补偿单元，90°相位变换单元和180°相位变换单元。其中，功分器的第一端口和合路点之间依次串联有相位补偿单元、第一PA和90°相位变换单元。功分器的第二端口和合路点之间依次串联有第二PA和180°相位变换单元。该射频前端电路具有较宽的工作带宽，并且该电路所占用面积较小。

Description

射频前端电路和电子设备
本申请要求于2022年9月27日提交中国专利局、申请号为202211184628.2、申请名称为“射频前端电路和电子设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电学领域，尤其涉及一种射频前端电路和电子设备。
背景技术
一般来说，频率低于100kHz的电磁波会被地表吸收，不能形成有效的传输。频率高于100kHz的电磁波可以在空气中传播，并经大气层外缘的电离层反射，形成远距离传输能力。这种具有远距离传输能力的高频电磁波可以称为射频。而在电子设备中，传输的电信号的频率较低，最高只有几百kHz，例如，语音信号。要将这些低频信号传输出去，就需要电子设备内的射频模块对电信号进行调制，从低频，调制到指定的高频频段，例如900MHz的全球移动通讯系统(global system for mobile communications，GSM)通信技术频段，1.9GHz的长期演进(long term evolution，LTE)通信技术频段，3.5GHz的第五代(fifth generation，5G)移动通信系统频段。
在射频模块中，电信号经过调制后，功率较小，还需要经过功率放大器(power amplifier，PA)的放大，使其获得足够的功率，然后才会送到天线模块，并通过天线模块向外部传输。其中，基于多赫蒂(Doherty)架构设计的PA具有功耗低、效率高、线性度较好等优点，被应用于射频模块中。但是，在多赫蒂(Doherty)架构中在主PA后引入90°相位变换单元，导致其宽带性能受限。而在倒置的Doherty架构中在原有的峰值PA后引入180°相位变换单元，拓展工作带宽，但二分之一阻抗变换单元的体积过大，很难在载板或芯片上实现。
发明内容
本申请提供一种射频前端电路和电子设备，射频前端电路具有较宽的工作带宽，并且该电路所占用面积较小。
第一方面，提供了一种射频前端电路，包括：功分器，第一功率放大器PA，第二PA，相位补偿单元，90°相位变换单元和180°相位变换单元；其中，所述功分器的公共端口与所述射频前端电路的输入端口电连接；所述相位补偿单元串联在所述功分器的第一端口和所述第一PA的第一端口之间；所述90°相位变换单元串联在所述第一PA的第二端口和合路点之间；所述第二PA串联在所述功分器的第二端口和所述180°相位变换单元的第一端口之间；所述180°相位变换单元的第二端口与所述合路点电连接；所述180°相位变换单元为耦合式变压器。
根据本申请实施例的技术方案，射频信号由功分器的公共端口输入，经由功分器分为两路射频信号(第一射频信号和第二射频信号)。第一射频信号经由相位补偿单元进行相位倒置(改变射频信号的相位)，而后第一射频信号由第一PA进行功率放大。功率放大后的第一射频信号传输至90°相位变换单元进行阻抗变换。第二射频信号经由第二PA进行功率放大，功率放大后的第二射频信号传输至180°相位变换单元进行相位变换。相位变换后的第一射频信号和阻抗变换后的第二射频信号在合路点处合成为第三射频信号。
结合第一方面，在第一方面的某些实现方式中，所述180°相位变换单元的第三端口和第四端口接地。
结合第一方面，在第一方面的某些实现方式中，所述180°相位变换单元包括相向设置的第一耦合件和第二耦合件；所述第一耦合件的第一端和所述第二耦合件的第一端位于第一侧，所述第一耦合件的第二端和所述第二耦合件的第二端位于第二侧；所述第一耦合件的第一端与所述180°相位变换单元的第一端口电连接，所述第一耦合件的第二端与所述180°相位变换单元的第三端口电连接；所述第二 耦合件的第一端与所述180°相位变换单元的第四端口电连接，所述第二耦合件的第二端与所述180°相位变换单元的第二端口电连接。
根据本申请实施例的技术方案，180°相位变换单元可以通过间接耦合的第一耦合件和第二耦合件实现输入的射频信号的相位变换，由于该部件相较于上述微带线或电路网络的结构来说，其占用面积较小，可以应用于芯片或电子设备中。
结合第一方面，在第一方面的某些实现方式中，所述第一耦合件和所述第二耦合件为金属线。
根据本申请实施例的技术方案，金属线可以呈直线型，或折线型，可以根据实际的布局决定。
结合第一方面，在第一方面的某些实现方式中，所述第一耦合件的长度和所述第二耦合件的长度不同。
根据本申请实施例的技术方案，第一耦合件或第二耦合件的长度以及宽度与射频信号经过180°相位变换单元进行的相位变换有关。例如，通过调整第一耦合件或第二耦合件的长度以及宽度可以控制射频信号经过180°相位变换单元改变的相位。
结合第一方面，在第一方面的某些实现方式中，所述射频前端电路还包括射频芯片；所述射频芯片包括输出端口；所述输出端口与所述功分器的公共端口电连接。
结合第一方面，在第一方面的某些实现方式中，所述射频前端电路还包括滤波器；所述滤波器与所述合路点电连接。
第二方面，提供了一种电子设备，包括：功分器，第一功率放大器PA，第二PA，相位补偿单元，90°相位变换单元和180°相位变换单元；其中，所述功分器的公共端口与所述射频前端电路的输入端口电连接；所述相位补偿单元串联在所述功分器的第一端口和所述第一PA的第一端口之间；所述90°相位变换单元串联在所述第一PA的第二端口和合路点之间；所述第二PA串联在所述功分器的第二端口和所述180°相位变换单元的第一端口之间；所述180°相位变换单元的第二端口与所述合路点电连接；所述180°相位变换单元为耦合式变压器。
结合第二方面，在第二方面的某些实现方式中，所述180°相位变换单元的第三端口和第四端口接地。
结合第二方面，在第二方面的某些实现方式中，所述180°相位变换单元包括相向设置的第一耦合件和第二耦合件；所述第一耦合件的第一端和所述第二耦合件的第一端位于第一侧，所述第一耦合件的第二端和所述第二耦合件的第二端位于第二侧；所述第一耦合件的第一端与所述180°相位变换单元的第一端口电连接，所述第一耦合件的第二端与所述180°相位变换单元的第三端口电连接；所述第二耦合件的第一端与所述180°相位变换单元的第四端口电连接，所述第二耦合件的第二端与所述180°相位变换单元的第二端口电连接。
结合第二方面，在第二方面的某些实现方式中，所述第一耦合件和所述第二耦合件为金属线。
结合第二方面，在第二方面的某些实现方式中，所述第一耦合件的长度和所述第二耦合件的长度不同。
结合第二方面，在第二方面的某些实现方式中，所述电子设备还包括射频芯片；所述射频芯片包括输出端口；所述输出端口与所述功分器的公共端口电连接。
结合第二方面，在第二方面的某些实现方式中，所述电子设备还包括天线模块；所述合路点与所述天线模块电连接。
结合第二方面，在第二方面的某些实现方式中，所述射频前端电路还包括滤波器；所述滤波器串联在所述天线模块与所述合路点之间。
附图说明
图1是本申请实施例提供的电子设备的示意图。
图2是本申请实施例提供的一种电子设备内部的电路示意图。
图3是本申请实施例提供的一种射频前端电路的示意图。
图4是本申请实施例提供的一种射频前端电路的示意图。
图5是本申请实施例提供的一种基于多赫蒂(Doherty)架构设计的射频前端电路。
图6是本申请实施例提供的一种倒置的Doherty架构设计的射频前端电路。
图7是图6所示射频前端电路的增益压缩曲线。
图8是图6所示射频前端电路的功率附加效率曲线。
图9是本申请实施例提供的两阶的电容-电感-电容网络。
图10是图9所示电路网络的相位的仿真结果。
图11是本申请实施例提供的一种射频前端电路100的示意图。
图12是本申请实施例提供的180°相位变换单元的原理图。
图13是本申请实施例提供的180°相位变换单元的结构示意图。
图14是本申请实施例提供的PA的电路连接示意图。
图15是180°相位变换单元142的相位的仿真结果。
图16是180°相位变换单元142的Q值的仿真结果。
图17是图11所示射频前端电路100的增益压缩曲线。
图18是图11所示射频前端电路100的功率附加效率曲线。
具体实施方式
下面将结合附图，对本申请实施例的技术方案进行描述。
如图1所示，电子设备10可以包括：盖板(cover)13、显示屏/模组(display)15、印刷电路板(printed circuit board，PCB)17、中框(middle frame)19和后盖(rear cover)21。应理解，在一些实施例中，盖板13可以是玻璃盖板(cover glass)，也可以被替换为其他材料的盖板，例如超薄玻璃材料盖板，PET(Polyethylene terephthalate，聚对苯二甲酸乙二酯)材料盖板等。
其中，盖板13可以紧贴显示模组15设置，可主要用于对显示模组15起到保护、防尘作用。
在一个实施例中，显示模组15可以包括液晶显示面板(liquid crystal display，LCD)，发光二极管(light emitting diode，LED)显示面板或者有机发光半导体(organic light-emitting diode，OLED)显示面板等，本申请实施例对此并不做限制。
中框19主要起整机的支撑作用。图1中示出PCB17设于中框19与后盖21之间，应可理解，在一个实施例中，PCB17也可设于中框19与显示模组15之间，本申请实施例对此并不做限制。其中，印刷电路板PCB17可以采用耐燃材料(FR-4)介质板，也可以采用罗杰斯(Rogers)介质板，也可以采用Rogers和FR-4的混合介质板，等等。这里，FR-4是一种耐燃材料等级的代号，Rogers介质板是一种高频板。PCB17上承载电子元件，例如，射频芯片等。在一个实施例中，印刷电路板PCB17上可以设置一金属层。该金属层可用于印刷电路板PCB17上承载的电子元件接地，也可用于其他元件接地，例如支架天线、边框天线等，该金属层可以称为地板，或接地板，或接地层。在一个实施例中，该金属层可以通过在PCB17中的任意一层介质板的表面蚀刻金属形成。在一个实施例中，用于接地的该金属层可以设置在印刷电路板PCB17上靠近中框19的一侧。在一个实施例中，印刷电路板PCB17的边缘可以看作其接地层的边缘。可以在一个实施例中，金属中框19也可用于上述元件的接地。电子设备10还可以具有其他地板/接地板/接地层，如前所述，此处不再赘述。
其中，电子设备10还可以包括电池(图中未示出)。电池可以设置于设于中框19与后盖21之间，或者可设于中框19与显示模组15之间，本申请实施例对此并不做限制。在一些实施例中，PCB17分为主板和子板，电池可以设于所述主板和所述子板之间，其中，主板可以设置于中框19和电池的上边沿之间，子板可以设置于中框19和电池的下边沿之间。
电子设备10还可以包括边框11，边框11可以由金属等导电材料形成。边框11可以设于显示模组15和后盖21之间并绕电子设备10的外围周向延伸。边框11可以具有包围显示模组15的四个侧边，帮助固定显示模组15。在一种实现方式中，金属材料制成的边框11可以直接用作电子设备10的金属边框，形成金属边框的外观，适用于金属工业设计(industrial design，ID)。在另一种实现方式中，边框11的外表面还可以为非金属材料，例如塑料边框，形成非金属边框的外观，适用于非金属ID。
中框19可以包括边框11，包括边框11的中框19作为一体件，可以对整机中的电子器件起支撑作用。盖板13、后盖21分别沿边框的上下边沿盖合从而形成电子设备的外壳或壳体(housing)。在一个实施例中，盖板13、后盖21、边框11和/或中框19，可以统称为电子设备10的外壳或壳体。应可理解，“外壳或壳体”可以用于指代盖板13、后盖21、边框11或中框19中任一个的部分或全部，或 者指代盖板13、后盖21、边框11或中框19中任意组合的部分或全部。
中框19上的边框11可以至少部分地作为天线辐射体以收/发射频信号，作为辐射体的这一部分边框，与中框19的其他部分之间可以存在间隙，从而保证天线辐射体具有良好的辐射环境。在一个实施例中，中框19在作为辐射体的这一部分边框处可以设置孔径，以利于天线的辐射。
或者，可以不将边框11看做中框19的一部分。在一个实施例中，边框11可以和中框19连接并一体成型。在另一实施例中，边框11可以包括向内延伸的突出件，以与中框19相连，例如，通过弹片、螺丝、焊接等方式相连。边框11的突出件还可以用来接收馈电信号，使得边框11的至少一部分作为天线的辐射体收/发射频信号。作为辐射体的这一部分边框，与中框30之间可以存在间隙，从而保证天线辐射体具有良好的辐射环境，使得天线具有良好的信号传输功能。
其中，后盖21可以是金属材料制成的后盖；也可以是非导电材料制成的后盖，如玻璃后盖、塑料后盖等非金属后盖；还可以是同时包括导电材料和非导电材料制成的后盖。
电子设备10的天线还可以设置于边框11内。当电子设备10的边框11为非导电材料时，天线辐射体可以位于电子设备10内并延边框11设置。例如，天线辐射体贴靠边框11设置，以尽量减小天线辐射体占用的体积，并更加的靠近电子设备10的外部，实现更好的信号传输效果。需要说明的是，天线辐射体贴靠边框11设置是指天线辐射体可以紧贴边框11设置，也可以为靠近边框11设置，例如天线辐射体与边框11之间能够具有一定的微小缝隙。
电子设备10的天线还可以设置于外壳内，例如支架天线、毫米波天线等(图1中未示出)。设置于壳体内的天线的净空可以由中框、和/或边框、和/或后盖、和/或显示屏中任一个上的开缝/开孔来得到，或者由任几个之间形成的非导电缝隙/孔径来得到，天线的净空设置可以保证天线的辐射性能。应可理解，天线的净空可以是由电子设备10内的任意导电元器件来形成的非导电区域，天线通过该非导电区域向外部空间辐射信号。在一个实施例中，天线40的形式可以为基于柔性主板(flexible printed circuit，FPC)的天线形式，基于激光直接成型(laser-direct-structuring，LDS)的天线形式或者微带天线(microstrip disk antenna，MDA)等天线形式。在一个实施例中，天线也可采用嵌设于电子设备10的屏幕内部的透明结构，使得该天线为嵌设于电子设备10的屏幕内部的透明天线单元。
图1仅示意性的示出了电子设备10包括的一些部件，这些部件的实际形状、实际大小和实际构造不受图1限定。
应理解，在本申请的实施例中，可以认为电子设备的显示屏所在的面为正面，后盖所在的面为背面，边框所在的面为侧面。
应理解，在本申请的实施例中，认为用户握持(通常是竖向并面对屏幕握持)电子设备时，电子设备所在的方位具有顶部、底部、左侧部和右侧部。
图2是本申请实施例提供的一种电子设备内部的电路示意图。
如图2所示，电子设备可以包括应用处理器(application processor，AP)，基带模块，数模转换器，射频模块和天线模块。
应用处理器可以用于运行开放式操作系统以及操作系统之上的各种应用，负责整个系统的控制。在向外部发射信号的过程中，应用处理器可以向基带模块传输数字信号，例如，语音信号。
基带模块可以用于对接收到的数字信号进行编码和调制，例如，在向外部发射电信号的过程中，基带模块通过对其进行编码和调制，使数字信号中信息所占用的空间更小，且可以对抗信道中的干扰和衰减，改善链路性能。
数模转换器可以用于将基带模块输出的数字信号转换为模拟信号，以便射频模块进行处理。或者，可以将射频模块输出的模拟信号转换为数字信号，以便基带模块进行处理。
射频模块可以用于对接收到的电信号的频率进行调制，并将功率放大。例如，在向外部发射电信号的过程中，射频模块通过对其进行调制，将模拟信号由低频调制到指定的高频频段，成为可在空气中传输的射频信号，并将射频信号的功率放大使其满足通信需求。
天线模块可以用于向外部发射经射频模块处理过的射频信号，或者，接收外部的电磁波信号并传输给射频模块。
图3和图4是本申请实施例提供的一种射频前端电路的示意图，射频前端电路可以是图2所示的射频模块当中靠近天线模块的部分。
如图3所示，射频前端电路可以包括射频芯片(RF IC)和射频前端模块(Front end module，FEM)。
其中，射频芯片可以用于对射频信号进行调制和解调，可以将射频信号进行上变频(提高射频信号的频率)和下变频(降低射频信号的频率)。PA可以设置在发射通道上，用于对发射的射频信号的功率进行放大。LNA可以设置在接收通道上，用于对天线模块接收到的射频信号的功率进行放大。开关可以用于在不同的时隙切换与天线模块连接的射频通道(发射通道或接收通道)。
在图3所示的利用开关的不同电连接状态(切换天线模块与发射通道或接收通道电连接)，可以使该射频前端电路工作在时分双工(time division dual，TDD)的通信系统。例如，在发射信号对应的时隙，开关切换至发射通道，使发射通道和天线模块电连接，射频信号通过发射通道传输至天线模块并向外部辐射。或者，在接收信号对应的时隙，开关切换至接收通道，使接收通道和天线模块电连接，天线模块接收到的射频信号通过接收通道传输至射频芯片进行处理。
在一个实施例中，该射频前端电路工作在频分双工(frequency division dual，FDD)的通信系统。射频前端电路还可以不包括开关，发射通道与接收通道分别与天线模块中的不同天线单元电连接，如图4所示。
图5是本申请实施例提供的一种基于多赫蒂(Doherty)架构设计的射频前端电路。
应理解，为了论述的简洁，本申请实施例仅以射频前端电路中的发射通道为例进行说明。
如图5所示，射频芯片产生的射频信号经由功分器分为第一射频信号和第二射频信号。第一射频信号经由主PA进行功率放大，并通过90°相位变换单元改变第一射频信号的相位使其进行阻抗变换。第二射频信号通过相位补偿单元改变第二射频信号的相位，使第二射频信号在合路点处与第一射频信号的相位相同，以便进行射频信号的合成，并经由峰值PA对第二射频信号的功率进行放大。第一射频信号和第二射频信号在合路点处合成第三射频信号，并传输至天线模块。
应理解，相位变换单元可以理解为阻抗变换单元，利用射频信号的相位变化实现阻抗变换。其中，90°相位变换单元可以理解为四分之一波长阻抗变换单元，180°相位变换单元可以理解为反相单元，射频信号经过180°相位变换单元后，相位相反(相位差为180°)。
在一个实施例中，主PA可以是AB类状态的功率放大器，例如，载波放大器。在一个实施例中，峰值PA可以是C类状态的功率放大器，例如，峰值放大器。
应理解，第一射频信号和第二射频信号经由主PA和峰值PA进行功率放大后，在合成点实现功率合成，完成功率放大的全过程。基于Doherty架构设计的PA电路具有功耗低、效率高等优点。
但是，在该架构下，由于在主PA后(主PA和合路点之间)引入90°相位变换单元，其为窄带器件，导致该架构下的射频前端电路的工作带宽受限。
图6是本申请实施例提供的一种倒置的Doherty架构设计的射频前端电路。
相较于图5所示的Doherty架构的射频前端电路，图6所示的射频电路，在峰值PA后(峰值PA和合路点之间)引入180°相位变换单元。通过180°相位变换单元的引入，可以拓展射频前端电路的工作带宽，使其可以应用于更多的通信频段。由于在峰值PA所在支路引入了180°相位变换单元，为保证在合路点处，经过峰值PA放大的射频信号与经过主PA的射频信号的相位相同，在主PA之前(主PA和功分器之间)引入了相位补偿单元。
图7和图8是图6所示的射频前端电路的仿真结果图。
应理解，在本申请实施例中，仅以射频前端电路的工作频段包括1.8GHz至2.6GHz为例进行说明，在实际的应用中，可以根据是的生产或设计调整。
如图7所示，以输出功率为31dBm为例，在工作频段内(频点1.8GHz、2.2GH和2.6GHz)增益波动在1.2dBm以内。
如图8所示，以输出功率为31dBm为例，在工作频段内(频点1.8GHz、2.2GH和2.6GHz)效率波动在5％以内。
在图6所示的射频前端电路中，180°相位变换单元通常由微带线或电容电感形成的电路实现。
当通过微带线作为180°相位变换单元，由于PA的输出端口的阻抗通常在5Ω左右，若在芯片的基板上通过微带实现该特征阻抗，微带线的线宽需要为1.4mm。同时，在sub3G频段(小于或等于3GHz)，通过微带线实现180°相位变换单元需要微带线的长度在20mm左右。无论微带线的线宽还是线长，该尺寸量级在芯片层面或者电子设备的载板上都是无法承受的，该方案仅适合基站等场景。
当通过电容电感形成的电路作为180°相位变换单元，由于PA的输出端口的阻抗较低，需要较大的并联电容，以sub3G频段为例，单颗电容需15pF。该电容值的电感若在芯片的基板上实现，以当前主流工艺的电容密度计算，单颗电容需要的芯片面积在17000um2。而对于电路中的电感来说，电感值大致为0.3nH，并且由于芯片的基板上的品质因数(Q factor，Q)值较低，及通流等问题，需增大电感的绕线的宽度至20um以上。
其中，Q值是衡量电感器件的主要参数。是指电感器件在某一频率的交流电压下工作时，所呈现的感抗与其等效损耗电阻之比。电感器件的Q值越高，其损耗越小效率越高。
此外，通过此方案实现180°的相位变换，需要两阶的电容-电感-电容网络，共计四颗电容，如图9中的(a)所示。不考虑避让等因素，仅电容的面积就达到56000um2。在一个实施例中，由电容电感形成的180度相位变换单元如图9中的(b)所示，其面积达到482um×301um。并且两阶的电容-电感-电容形成的网络在工作频段内的相位波动较大，接近100°，效果较差，如图10所示。若要减小相位波动，需要级联更多阶的网络。
同时因为电容值较大，还需结合具体工艺评估，该电容是否会将射频信号旁路，进而需要对较大的电容值的电容进行拆分，增大了布局布线难度，也进一步增大了该单元的面积，也会引入更多的寄生参数，加大设计难度。
本申请实施例提供了一种射频前端电路，可以应用于图1所示的电子设备中，该射频前端电路具有较宽的工作带宽，并且该电路所占用面积较小。
图11是本申请实施例提供的一种射频前端电路100的示意图，可以应用于图1所示的电子设备中。
如图11所示，射频前端电路100可以包括功分器110，第一PA121，第二PA122，相位补偿单元130，90°相位变换单元141和180°相位变换单元142。
其中，功分器110的公共端口111与射频前端电路100的输入端口电连接.。在一个实施例中，功分器110可以用于将传输至公共端口111的射频信号分为传输至第一端口112的第一射频信号101和传输至第二端口113的第二射频信号102。
相位补偿单元130串联在功分器110的第一端口112和第一PA121的第一端口1211之间。相位补偿单元130的第一端口与功分器110的第一端口112电连接，相位补偿单元130的第二端口与第一PA121的第一端口1211电连接。在一个实施例中，相位补偿单元130可以用于实现第一射频信号101的相位倒置。
90°相位变换单元141串联在第一PA121的第二端口1212和合路点150之间。90°相位变换单元141的第一端口与第一PA121的第二端口1212电连接，90°相位变换单元141的第二端口与合路点150电连接。在一个实施例中，90°相位变换单元141可以用于改变第一射频信号的相位使其进行阻抗变换。
第二PA122串联在功分器110的第二端口113和180°相位变换单元142的第一端口之间。第二PA122的第一端口1221与功分器110的第二端口113电连接，第二PA122的第二端口1222与180°相位变换单元142的第一端口1421电连接。在一个实施例中，180°相位变换单元142可以用于改变第二射频信号的相位，使第二射频信号的相位相反(例如，与相位变换前的相位之差为180°±10°)。180°相位变换单元142的第二端口1422与合路点150电连接。180°相位变换单元142为耦合式变压器。
应理解，射频信号由功分器110的公共端口111输入，经由功分器110分为两路射频信号(第一射频信号101和第二射频信号102)。第一射频信号101经由相位补偿单元130进行相位倒置(改变射频信号的相位)，而后第一射频信号101由第一PA121进行功率放大。功率放大后的第一射频信号101传输至90°相位变换单元141进行阻抗变换。第二射频信号102经由第二PA122进行功率放大，功率放大后的第二射频信号102传输至180°相位变换单元142进行相位变换。阻抗变换后的第一射频信号101和相位变换后的第二射频信号102在合路点150处合成为第三射频信号103。
在一个实施例中，合路点150可以与天线模块200电连接，第三射频信号103可以通过天线模块200向外辐射。
在一个实施例中，第一PA121可以是上述实施例中Doherty架构下的主PA。在一个实施例中，第二PA122可以是上述实施例中Doherty架构下的峰值PA。
在一个实施例中，180°相位变换单元142还可以包括第三端口1423和第四端口1424。第三端口 1423和第四端口1424可以与电子设备中的地板电连接，实现接地。
在一个实施例中，180°相位变换单元142可以包括第一耦合件143和第二耦合件144，如图12所示。第一耦合件143和第二耦合件144可以相向(face to face)设置。第一耦合件143的第一端和第二耦合件144的第一端位于第一侧，第一耦合件143的第二端和第二耦合件144的第二端位于第二侧。第一耦合件143的第一端与180°相位变换单元142的第一端口1421电连接，第一耦合件143的第二端与180°相位变换单元142的第三端口1423电连接。第二耦合件144的第一端与180°相位变换单元142的第四端口1424电连接，第二耦合件144的第二端与180°相位变换单元142的第二端口1422电连接。
180°相位变换单元142可以通过间接耦合的第一耦合件143和第二耦合件144实现输入的射频信号的相位变换，由于该部件相较于上述微带线或电路网络的结构来说，其占用面积较小，可以应用于芯片或图1所示的电子设备中。
应理解，图12所示的180°相位变换单元142为180°相位变换单元142的原理图，在实际的应用中，180°相位变换单元142可以为图13所示的结构，第一耦合件143和第二金属耦合件144可以为金属线。在一个实施例中，金属线可以呈直线型，或折线型，可以根据实际的布局决定。
同时，180°相位变换单元142可以进行封装，也可以设置在芯片或PCB的基板上。当第一耦合件143和第二耦合件144设置在基板上时，上述第一耦合件143的第一端与180°相位变换单元142的第一端口1421相同，第一耦合件143的第二端与180°相位变换单元142的第三端口1423相同，第二耦合件144的第一端与180°相位变换单元142的第四端口1424相同，第二耦合件144的第二端与180°相位变换单元142的第二端口1422相同。
在一个实施例中，当第一耦合件143和第二耦合件144设置在基板上时，第一耦合件143的长度可以和第二耦合件144的长度相同或者不同，或者，第一耦合件143的宽度可以和第二耦合件144的宽度相同或者不同。第一耦合件143或第二耦合件144的长度以及宽度与射频信号经过180°相位变换单元142进行的相位变换有关。例如，通过调整第一耦合件143或第二耦合件144的长度以及宽度可以控制射频信号经过180°相位变换单元142改变的相位。
在一个实施例中，当射频前端电路的工作频段包括1.6GHz-1.8GHz时，第一耦合件143或第二耦合件144的长度可以小于或等于1500um。
在一个实施例中，当射频前端电路的工作频段包括3.3GHz-5GHz中的部分频段时，第一耦合件143或第二耦合件144的长度可以小于或等于900um。
在一个实施例中，第一耦合件143的宽度或第二耦合件144的宽度可以小于或等于80um。
应理解，由耦合式变压器作为180°相位变换单元，可以大幅缩小180°相位变换单元所占用的面积，使其应用于芯片或电子设备中。
在一个实施例中，在工作频段内，180°相位变换单元142的Q值可以大于或等于15，减少180°相位变换单元142中传输的射频信号的损耗，提升射频前端电路的性能。
应理解，在电子设备或芯片中，可以根据布局的需求，调整第一耦合件143或第二耦合件144的排布方式，例如，可以呈折线型等，本申请对此并不做限制。
在一个实施例中，第一PA121或第二PA122还可以包括第三端口，第四端口和第五端口，如图14所示。第三端口和第四端口可以与电源电连接，第五端口可以用于接地，以使第一PA121或第二PA122工作。
在一个实施例中，射频前端电路100还可以包括射频芯片160。射频芯片160的输出端口可以与功分器110的公共端口111电连接，用于向功分器110传输射频信号。
在一个实施例中，射频前端电路还可以包括滤波器170。滤波器170可以串联在合路点150和天线模块200之间，可以用于滤除第三射频信号103中的杂波。
图15和图16是图11所示射频前端电路100中180°相位变换单元142的仿真结果。其中，图15是180°相位变换单元142的相位的仿真结果。图16是180°相位变换单元142的Q值的仿真结果。
应理解，在本申请实施例中，仅以射频前端电路的工作频段包括1.8GHz至2.6GHz为例进行说明，在实际的应用中，可以根据是的生产或设计调整。
如图15所示，在1.8GHz至2.6GHz的频段范围内，相位的波动仅为8°左右，具有良好的宽带特性，优于微带线结构及电容-电感-电容网络，用该结构实现的反相单元，可令宽带性能更加收敛。
如图16所述，在1.8GHz至2.6GHz的频段范围内，其Q值(Qs、Qp)可以大于15。相较于电容-电感-电容网络，180°相位变换单元的Q值大幅提升(绕线电感的Q值仅有10左右)，可以有效减少射频信号的损耗，提升射频前端电路的性能。
其中，Qs、Qp可以理解为由S波所得出的介质品质因数和由P波得出的品质因数。两者的值是不相同的。
图17和图18是图11所示射频前端电路100的仿真结果。其中，图17是图11所示射频前端电路100的增益压缩曲线。图18是图11所示射频前端电路100的功率附加效率曲线。
如图17所示，以输出功率为31dBm为例，在工作频段内(频点1.8GHz、2.2GH和2.6GHz)增益波动在1.2dBm以内。
如图18所示，以输出功率为31dBm为例，在工作频段内(频点1.8GHz、2.2GH和2.6GHz)效率波动在5％以内。
并且，在1.8GHz至2.6GHz(相对带宽达到36.3％)的频段内，仿真所得增益压缩曲线及功率附加效率具有较好的宽带一致性，饱和功率基本一致。
本领域技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统和装置，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的之间接耦合或通信连接，可以是电性或其它的形式。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (15)

  1. 一种射频前端电路，其特征在于，包括：
    功分器，第一功率放大器PA，第二PA，相位补偿单元，90°相位变换单元和180°相位变换单元；
    其中，所述功分器的公共端口与所述射频前端电路的输入端口电连接；
    所述相位补偿单元串联在所述功分器的第一端口和所述第一PA的第一端口之间；
    所述90°相位变换单元串联在所述第一PA的第二端口和合路点之间；
    所述第二PA串联在所述功分器的第二端口和所述180°相位变换单元的第一端口之间；
    所述180°相位变换单元的第二端口与所述合路点电连接；
    所述180°相位变换单元为耦合式变压器。
  2. 根据权利要求1所述的射频前端电路，其特征在于，
    所述180°相位变换单元的第三端口和第四端口接地。
  3. 根据权利要求2所述的射频前端电路，其特征在于，
    所述180°相位变换单元包括相向设置的第一耦合件和第二耦合件；
    所述第一耦合件的第一端和所述第二耦合件的第一端位于第一侧，所述第一耦合件的第二端和所述第二耦合件的第二端位于第二侧；
    所述第一耦合件的第一端与所述180°相位变换单元的第一端口电连接，所述第一耦合件的第二端与所述180°相位变换单元的第三端口电连接；
    所述第二耦合件的第一端与所述180°相位变换单元的第四端口电连接，所述第二耦合件的第二端与所述180°相位变换单元的第二端口电连接。
  4. 根据权利要求3所述的射频前端电路，其特征在于，所述第一耦合件和所述第二耦合件为金属线。
  5. 根据权利要求3或4所述的射频前端电路，其特征在于，所述第一耦合件的长度和所述第二耦合件的长度不同。
  6. 根据权利要求1至5中任一项所述的射频前端电路，其特征在于，
    所述射频前端电路还包括射频芯片；
    所述射频芯片包括输出端口；
    所述输出端口与所述功分器的公共端口电连接。
  7. 根据权利要求1至6中任一项所述的射频前端电路，其特征在于，
    所述射频前端电路还包括滤波器；
    所述滤波器与所述合路点电连接。
  8. 一种电子设备，其特征在于，包括：
    功分器，第一功率放大器PA，第二PA，相位补偿单元，90°相位变换单元和180°相位变换单元；
    其中，所述功分器的公共端口与所述射频前端电路的输入端口电连接；
    所述相位补偿单元串联在所述功分器的第一端口和所述第一PA的第一端口之间；
    所述90°相位变换单元串联在所述第一PA的第二端口和合路点之间；
    所述第二PA串联在所述功分器的第二端口和所述180°相位变换单元的第一端口之间；
    所述180°相位变换单元的第二端口与所述合路点电连接；
    所述180°相位变换单元为耦合式变压器。
  9. 根据权利要求8所述的电子设备，其特征在于，
    所述180°相位变换单元的第三端口和第四端口接地。
  10. 根据权利要求9所述的电子设备，其特征在于，
    所述180°相位变换单元包括相向设置的第一耦合件和第二耦合件；
    所述第一耦合件的第一端和所述第二耦合件的第一端位于第一侧，所述第一耦合件的第二端和所述第二耦合件的第二端位于第二侧；
    所述第一耦合件的第一端与所述180°相位变换单元的第一端口电连接，所述第一耦合件的第二端 与所述180°相位变换单元的第三端口电连接；
    所述第二耦合件的第一端与所述180°相位变换单元的第四端口电连接，所述第二耦合件的第二端与所述180°相位变换单元的第二端口电连接。
  11. 根据权利要求10所述的电子设备，其特征在于，所述第一耦合件和所述第二耦合件为金属线。
  12. 根据权利要求10或11所述的电子设备，其特征在于，所述第一耦合件的长度和所述第二耦合件的长度不同。
  13. 根据权利要求8至12中任一项所述的电子设备，其特征在于，
    所述电子设备还包括射频芯片；
    所述射频芯片包括输出端口；
    所述输出端口与所述功分器的公共端口电连接。
  14. 根据权利要求8至13中任一项所述的电子设备，其特征在于，
    所述电子设备还包括天线模块；
    所述合路点与所述天线模块电连接。
  15. 根据权利要求14所述的电子设备，其特征在于，
    所述射频前端电路还包括滤波器；
    所述滤波器串联在所述天线模块与所述合路点之间。
PCT/CN2023/119424 2022-09-27 2023-09-18 射频前端电路和电子设备 WO2024067211A1 (zh)

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CN107431461A (zh) * 2015-02-15 2017-12-01 天工方案公司 具有am‑am补偿的多尔蒂功率放大器
CN105245192A (zh) * 2015-10-31 2016-01-13 中国人民解放军空军工程大学 一种多尔蒂功率放大器
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