Coupler circuit, radio frequency chip and radio frequency packaging module

Abstract

The invention relates to the technical field of wireless communication, and provides a coupler circuit, a radio frequency chip and a radio frequency packaging module, and the coupler circuit comprises a substrate, and a radio frequency switch circuit, an input matching circuit, a coupler and a load matching circuit which are arranged on the substrate; the input end of the radio frequency switch circuit is connected with a radio frequency signal, the output end of the radio frequency switch circuit is connected with the input end of the input matching circuit, and the radio frequency switch circuit is used for switching the radio frequency signal needing to be connected; the output end of the input matching circuit is connected to the coupler and is used for adjusting the impedance of the coupler; the coupler is used for coupling and outputting an input signal; the coupler comprises a straight-through line and a coupling line coupled with the straight-through line, two ends of the straight-through line are respectively provided with an input port and an output port, and two ends of the coupling line are respectively provided with a coupling port and an isolation port; the output end of the input matching circuit is connected with the input port of the coupler, and the output end of the coupler is used for connecting an antenna. According to the coupler circuit, the radio frequency performance and the performance index can be improved.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a coupler circuit, a radio frequency chip and a radio frequency packaging module. Background Art

[0002] With the update and iteration of wireless communication equipment, its performance is constantly improving; directional coupler is an important component of modern wireless communication system. In the RF front-end module, it is mainly integrated into the antenna switch, located at the front end of the antenna, detecting forward power and reverse power, and checking the status of the antenna.

[0003] For mobile applications, RF front-end modules need to be highly integrated, and the coupling coefficient and size of the coupler in the antenna switch component change with the frequency, and they need to be compromised. Under the premise of meeting the coupling coefficient, it is particularly important to reasonably use the smallest area to achieve a directivity of more than 20dB in the module. With the rapid development of wireless communications and integrated circuits, the frequency bands and functional modes required for mobile phone operation are increasing, and the number of channels required for an antenna switch is increasing, which places higher and higher performance requirements on the coupler integrated inside the antenna.

[0004] In the traditional Sub3G RF module antenna switch, the coupler circuit design structure is as follows Figure 1 As shown. In this architecture, the performance of the coupler coil 11 itself will be limited by the number of switching channels of the RF switch 10. After adding the RF switch and the packaging module, the impedance of the coupler's input port 1 and output port 2 will be seriously mismatched. The signal mismatch of the port of the antenna 12 will also cause the impedance mismatch of the coupler's straight-through end. As a result, the performance of the coupling port 3 and the isolation port 4 deviates from the performance of the coupler coil 11 itself, and the directivity becomes worse. At the same time, although this structure can add matching to the switch path of the packaging module to adjust the coupler performance, as the number of switching paths increases, the number of matching paths will also increase, which will greatly increase the packaging cost. Summary of the invention

[0005] In view of the above deficiencies in the prior art, the present invention proposes a coupler circuit, a radio frequency chip and a radio frequency packaging module to solve the problems of poor radio frequency performance and high production cost of the existing coupler circuit.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions: In a first aspect, an embodiment of the present invention provides a coupler circuit, comprising a substrate, a radio frequency switch circuit, an input matching circuit, a coupler and a load matching circuit arranged on the substrate; the input end of the radio frequency switch circuit is used to access a radio frequency signal, the output end of the radio frequency switch circuit is connected to the input end of the input matching circuit, and the radio frequency switch circuit is used to switch the radio frequency signal to be connected; the output end of the input matching circuit is connected to the coupler, and is used to adjust the impedance of the coupler; the coupler is used to couple the input signal to output; The coupler includes a straight-through line and a coupled line coupled with the straight-through line, the two ends of the straight-through line are respectively provided with an input port and an output port, and the two ends of the coupled line are respectively provided with a coupling port and an isolation port; the output end of the input matching circuit is connected to the input port of the coupler, and the output end of the coupler is used to connect an antenna, the input port corresponds to the coupling port, the output port corresponds to the isolation port, and the isolation port is connected in series with the load matching circuit and then grounded.

[0007] Preferably, the input matching circuit includes a first capacitor, a first inductor and a second inductor; The first end of the first capacitor is respectively connected to the first end of the first inductor and the first end of the second inductor and together serve as the input end of the input matching circuit, and the second end of the second inductor is grounded; the second end of the first capacitor is connected to the second end of the first inductor and together serve as the output end of the input matching circuit.

[0008] Preferably, the RF switch circuit includes n switches connected in parallel, wherein n is a positive integer; the output end of each switch serves as the input end of the RF switch circuit, and the control ends of all the switches are connected to each other and serve as the output end of the RF switch circuit.

[0009] Preferably, the load matching circuit includes a first resistor and a second capacitor, the first end of the first resistor is connected to the first end of the second capacitor and are commonly connected to the isolation port; the second end of the first resistor is connected to the second end of the second capacitor and are commonly grounded.

[0010] Preferably, the radio frequency switch circuit, the input matching circuit, the coupler and the load matching circuit are respectively integrated on the substrate.

[0011] In a second aspect, an embodiment of the present invention provides a radio frequency chip, comprising the above-mentioned coupler circuit.

[0012] In a third aspect, an embodiment of the present invention provides a radio frequency packaging module, comprising the above-mentioned coupler circuit.

[0013] Compared with the related art, in an embodiment of the present invention, the input end of the RF switch circuit is used to access the RF signal, and the output end of the RF switch circuit is connected to the input end of the input matching circuit, and the RF switch circuit is used to switch the RF signal to be connected; the output end of the input matching circuit is connected to the coupler, which is used to adjust the impedance of the coupler; the coupler is used to couple the input signal to output; the two ends of the straight-through line of the coupler are respectively provided with an input port and an output port, and the two ends of the coupling line are respectively provided with a coupling port and an isolation port; the output end of the input matching circuit is connected to the input port of the coupler, and the output end of the coupler is used to connect the antenna, the input port corresponds to the coupling port, the output port corresponds to the isolation port, and the isolation port is connected in series with the load matching circuit and then grounded; through a set of simple input matching circuit matching methods, it is possible to achieve that each path of the RF switch reaches the antenna through the coupler, and its directional performance and the insertion loss of the straight-through end link can be kept optimal, and the complexity of the packaging module and the cost of the RF front-end module are greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be described in detail below in conjunction with the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings. In the accompanying drawings: Figure 1 A circuit structure block diagram of a coupler circuit provided by the prior art; Figure 2 A circuit structure block diagram of a coupler circuit provided in an embodiment of the present invention; Figure 3 A schematic diagram showing a directivity comparison result between a coupler circuit provided in an embodiment of the present invention and a coupler circuit in the prior art; Figure 4 A schematic diagram showing a comparison of antenna link insertion losses of a coupler circuit provided in an embodiment of the present invention and a coupler circuit in the prior art.

[0015] Among them, 100, coupler circuit, 101, substrate, 102, RF switch circuit, 103, input matching circuit, 104, coupler, 141, through line, 142, coupling line, 105, load matching circuit, 200, RF packaging module. DETAILED DESCRIPTION

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0017] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Embodiment 1 See also Figure 1-Figure 4 As shown, an embodiment of the present invention provides a coupler circuit 100, including a substrate 101, a radio frequency switch circuit 102, an input matching circuit 103, a coupler 104 and a load matching circuit 105 arranged on the substrate 101; the input end of the radio frequency switch circuit 102 is used to access the radio frequency signal, the output end of the radio frequency switch circuit 102 is connected to the input end of the input matching circuit 103, and the radio frequency switch circuit 102 is used to switch the radio frequency signal to be accessed; the output end of the input matching circuit 103 is connected to the coupler 104, which is used to adjust the impedance of the coupler 104; the coupler 104 is used to couple the input signal to output. Optionally, the radio frequency switch circuit 102, the input matching circuit 103, the coupler 104 and the load matching circuit 105 can be integrated or installed on the substrate 101.

[0020] The coupler 104 includes a straight-through line 141 and a coupling line 142 coupled with the straight-through line 141, the two ends of the straight-through line 141 are respectively provided with an input port and an output port, the two ends of the coupling line 142 are respectively provided with a coupling port and an isolation port; the output end of the input matching circuit 103 is connected to the input port of the coupler, the output end of the coupler 104 is used to connect the antenna, the input port corresponds to the coupling port, the output port corresponds to the isolation port, and the isolation port is connected to the ground after being connected in series with the load matching circuit 105. Through a set of simple input matching circuits 103, each path of the RF switch can reach the antenna through the coupler 104, and its directional performance and the insertion loss of the straight-through end link can be kept optimal, and the complexity of the packaging module and the cost of the RF front-end module are greatly reduced. At the same time, except for the input matching circuit 103 in the SOI antenna switch, other ports including the entire packaging module do not need to be matched. Among them, SOI (Silicon-On-Insulator) process, also known as silicon on insulating substrate technology, is a semiconductor manufacturing technology that introduces a buried oxide layer (SiO2) between the top silicon and the back substrate. This unique Si / SiO2 / Si structure achieves full dielectric isolation between the device and the substrate, thereby reducing parasitic capacitance, increasing operating speed, reducing power consumption, and eliminating latch-up effects.

[0021] In this embodiment, the input matching circuit 103 includes a first capacitor C1, a first inductor L1 and a second inductor L2; the first end of the first capacitor C1 is respectively connected to the first end of the first inductor L1 and the first end of the second inductor L2 and serves as the input end of the input matching circuit 103, and the second end of the second inductor L2 is grounded; the second end of the first capacitor C1 is connected to the second end of the first inductor L1 and serves as the output end of the input matching circuit 103. In the SOI antenna switch, the input matching circuit 103 is added at the connection between the coupler 104 and the RF switch circuit 102. The input matching circuit 103 is used to adjust the impedance of the through port of the coupler 104. The first capacitor C1 and the first inductor L1 are connected in parallel to the input port of the through line 141 of the coupler 104 and the RF switch circuit 102, and then the second inductor L2 is added in parallel. There is no restriction on the switch path and structure of the RF switch circuit 102. The number of paths can be more than 2, and the structure can be SPnT or DTnT. The values ​​of the first inductor L1 , the first capacitor C1 , and the second inductor L2 in the matching circuit are determined according to the structure and path of the RF switch circuit 102 and the impedance shift caused by the layout and routing of the RF signal in the packaging module.

[0022] In this embodiment, the RF switch circuit 102 includes n switches (S1, S2 and S3) connected in parallel, where n is a positive integer; the output end of each switch serves as the input end of the RF switch circuit 102, and the control ends of all the switches are connected to each other and serve as the output end of the RF switch circuit 102. By switching the RF signals to be connected through different switches, and outputting the RF signals of different frequency bands to the input matching circuit 103 for input matching, and then outputting them to the through line 141 of the coupler 104 after matching, each path of the RF switch can reach the antenna through the coupler 104, and its directional performance and the insertion loss of the through-end link can be kept optimal, and the complexity of the RF packaging module 200 and the cost of the RF front-end module are greatly reduced.

[0023] In this embodiment, the load matching circuit 105 includes a first resistor R1 and a second capacitor C2, wherein the first end of the first resistor R1 and the first end of the second capacitor C2 are connected to the isolation port; the second end of the first resistor R1 and the second end of the second capacitor C2 are connected to the ground. By connecting the first resistor R1 and the second capacitor C2 to the isolation port, the isolation of the isolation port can be improved, and the isolation port is prevented from being slightly mismatched near the impedance value of 50Ω (Ohm), thereby improving the directivity of the overall circuit.

[0024] In this embodiment, the RF switch circuit 102, the input matching circuit 103, the coupler 104 and the load matching circuit 105 are respectively integrated on the substrate 101. The substrate 101 is made of SOI technology and belongs to a chip-level circuit board. Its size will be smaller, and the unit is nm, so that the accuracy of the substrate 101 is better.

[0025] In this embodiment, Figure 3 This is the directivity comparison result of the prior art and this embodiment in the Sub3G frequency band. At the same frequency, such as 1.8GHz, the directivity coefficient of the prior art is M1=7.53053dB, while that of this embodiment is M2=22.501dB; at the frequency of 2.1GHz, the directivity coefficient of the prior art is M4=6.53125dB, while that of this embodiment is M3=23.0849dB; the advantages of this embodiment can be clearly seen from the results shown in the figure, and the improvement in directivity is obvious.

[0026] Figure 4It is a comparison result of the insertion loss of the direct-through link of the coupler 104 in the Sub3G frequency band between the prior art and the present embodiment. At the same frequency such as 1.8GHz, the insertion loss of the prior art is M1=-702.19mdB, while that of the present embodiment is M3=-579.003mdB; at the frequency of 2.1GHz, the insertion loss of the prior art is M2=-836.484mdB, while that of the present embodiment is M4=-655.567mdB; the advantages of the present embodiment can be clearly seen from the results shown in the figure, and the insertion loss of the direct-through end of the coupler 104, including the RF switch path to the antenna link, is significantly improved. Therefore, the present invention can realize that each path of the RF switch reaches the antenna through the coupler 104 through a set of simple input matching circuits 103, and its directional performance and the insertion loss of the direct-through link can be kept optimal, and the complexity of the packaging module and the cost of the RF front-end module are greatly reduced.

[0027] Embodiment 2 An embodiment of the present invention provides a radio frequency chip, including the coupler circuit as described above. The technical effect produced by the radio frequency chip is the same as that of the coupler circuit as described above, and will not be described here.

[0028] Embodiment 3 The embodiment of the present invention provides a radio frequency packaging module 200, comprising the above-mentioned coupler circuit. The technical effect produced by the radio frequency packaging module 200 is the same as that of the above-mentioned radio frequency chip, and will not be described here.

[0029] It should be noted that the various embodiments described above with reference to the accompanying drawings are only used to illustrate the present invention rather than to limit the scope of the present invention. Those skilled in the art should understand that any modification or equivalent substitution of the present invention without departing from the spirit and scope of the present invention should be included within the scope of the present invention. In addition, unless otherwise indicated by the context, words appearing in the singular include the plural form, and vice versa. In addition, unless otherwise specified, all or part of any embodiment may be used in combination with all or part of any other embodiment.

Claims

1. A coupler circuit, characterized in that: The invention comprises a substrate, a radio frequency switch circuit, an input matching circuit, a coupler and a load matching circuit arranged on the substrate; the input end of the radio frequency switch circuit is used to access the radio frequency signal, the output end of the radio frequency switch circuit is connected to the input end of the input matching circuit, and the radio frequency switch circuit is used to switch the radio frequency signal to be connected; the output end of the input matching circuit is connected to the coupler to adjust the impedance of the coupler; the coupler is used to couple the input signal to output; The coupler includes a straight-through line and a coupled line coupled with the straight-through line, the two ends of the straight-through line are respectively provided with an input port and an output port, and the two ends of the coupled line are respectively provided with a coupling port and an isolation port; the output end of the input matching circuit is connected to the input port of the coupler, and the output end of the coupler is used to connect an antenna, the input port corresponds to the coupling port, the output port corresponds to the isolation port, and the isolation port is connected in series with the load matching circuit and then grounded.

2. The coupler circuit according to claim 1, characterized in that The input matching circuit includes a first capacitor, a first inductor and a second inductor; The first end of the first capacitor is respectively connected to the first end of the first inductor and the first end of the second inductor and together serve as the input end of the input matching circuit, and the second end of the second inductor is grounded; the second end of the first capacitor is connected to the second end of the first inductor and together serve as the output end of the input matching circuit.

3. The coupler circuit according to claim 1, characterized in that The radio frequency switch circuit includes n switches connected in parallel, wherein n is a positive integer; the output end of each switch serves as the input end of the radio frequency switch circuit, and the control ends of all the switches are connected to each other and serve as the output end of the radio frequency switch circuit.

4. The coupler circuit according to claim 1, characterized in that The load matching circuit includes a first resistor and a second capacitor, wherein a first end of the first resistor is connected to a first end of the second capacitor and is commonly connected to the isolation port; and a second end of the first resistor is connected to a second end of the second capacitor and is commonly grounded.

5. The coupler circuit according to claim 1, characterized in that The radio frequency switch circuit, the input matching circuit, the coupler and the load matching circuit are respectively integrated on the substrate.

6. A radio frequency chip, characterized in that: Comprising the coupler circuit as claimed in any one of claims 1 to 5.

7. A radio frequency packaging module, characterized in that: Comprising the coupler circuit of claim 6.

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