Radio frequency receiving front-end circuit based on coupling structure

Abstract

The invention discloses a radio frequency receiving front-end circuit based on a coupling structure, which comprises a receiving filter and a low noise amplifier, the receiving filter is composed of three filtering resonators and an impedance matching capacitor inductor, and the low noise amplifier is composed of a primary cascode amplifying circuit and a noise matching capacitor inductor. Meanwhile, the receiving filter and the low-noise amplifier are connected in a coupling structure mode, the size of the whole radio frequency receiving front-end circuit can be reduced, the cost is reduced, the impedance matching effect between the filter and the low-noise amplifier is improved, and the radio frequency receiving front-end circuit can be widely applied to the field of wireless communication circuit design.

Description

Technical Field

[0001] The present invention relates to the field of wireless communications, and in particular to a radio frequency receiving front-end circuit. Background Art

[0002] The RF receiving front-end circuit is the core component of the wireless communication terminal. It is located in the middle of the antenna and the transceiver chip and plays the role of signal amplification, filtering, and channel switching. With the rapid development of wireless communication terminals in recent years, the integrated functions are increasing, which requires the RF receiving front-end circuit to be as small as possible. However, due to the continuous increase in interference frequency bands in wireless communications, the requirements for the receiving filter of the RF receiving front-end circuit are getting higher and higher, and it is becoming more and more difficult to reduce the size of the RF front-end circuit. The use of advanced integrated circuit manufacturing technology, multi-layer substrate technology and other technologies can reduce the size of the RF front-end circuit to a certain extent, but the corresponding circuit manufacturing cost will increase significantly. Summary of the invention

[0003] In view of this, in order to solve the problems in the above-mentioned prior art, the present invention proposes a RF receiving front-end circuit based on a coupling structure. By connecting the filter and the low-noise amplifier in the RF receiving front-end circuit in a coupled manner, the size of the overall RF receiving front-end circuit is reduced, the cost is reduced, and the impedance matching effect between the filter and the low-noise amplifier is improved.

[0004] To achieve the above object, the technical solution of the present invention is as follows:

[0005] A radio frequency receiving front-end circuit based on a coupling structure comprises a receiving filter and a low noise amplifier.

[0006] Furthermore, the receiving filter includes a first parallel resonator, a first parallel inductor, a first series capacitor, a first series resonator, a second series capacitor, and a second series resonator. The first parallel resonator is composed of a first inductor and a first capacitor in parallel, the first series resonator is composed of a second inductor and a second capacitor in series, and the second series resonator is composed of a third inductor and a third capacitor in series.

[0007] Furthermore, the first parallel resonator is connected to the input end of the filter and the first parallel inductor, the first series resonator is connected to the first series capacitor and the second series capacitor, and the second series resonator is connected to the second series capacitor and the output end of the filter.

[0008] Through the above circuit structure, the first parallel resonator, the first series resonator and the second series resonator are used to filter out signals of three different interference frequency bands, and the first parallel inductor, the first series capacitor and the second series capacitor are used to complete the impedance matching of the receiving filter.

[0009] Furthermore, the low-noise amplifier includes a common-source amplifier module circuit and a common-gate amplifier module circuit, the common-source amplifier module circuit includes a first series inductor, a first transistor, a first feed resistor, a first feed capacitor, and a first ground inductor, the common-gate amplifier module circuit includes a second transistor, a second feed resistor, a second feed capacitor, a first output inductor, a second output inductor, and a first output capacitor, and the drain of the first transistor of the common-source amplifier module circuit is connected to the source of the second transistor of the common-gate amplifier module circuit.

[0010] Furthermore, the first series inductor is connected to the input end of the low noise amplifier and the first feeding resistor, the gate of the first transistor is connected to the first feeding resistor, the source of the first transistor is connected to the first grounding inductor, the drain of the first transistor is connected to the source of the second transistor, the gate of the second transistor is connected to the second feeding resistor, the drain of the second transistor is connected to the ground output inductor and the second output inductor, and the first output capacitor is connected to the second output inductor and the output end of the low noise amplifier.

[0011] Through the above circuit structure, the common-source amplifier circuit module and the common-gate amplifier circuit module constitute a common-source and common-gate amplifier circuit to achieve signal amplification.

[0012] Furthermore, the third inductor of the receiving filter and the first series inductor of the low noise amplifier are connected by winding coupling.

[0013] Through the above circuit structure, the overall size of the RF receiving front end can be reduced by the area of ​​an inductor, thereby reducing the cost. In addition, the filter and the low-noise amplifier can obtain a better impedance matching effect.

[0014] Compared with the prior art, the RF receiving front-end circuit based on the coupler structure of the present invention has the following beneficial effects and advantages:

[0015] (1) The circuit is connected by coupling to reduce the circuit size.

[0016] (2) The circuit reduces costs by coupling connection

[0017] (3) The circuit is connected by coupling, and the impedance matching effect between the filter and the low noise amplifier is better BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The schematic diagram of the principle of a radio frequency receiving front-end circuit based on a coupling structure of the present invention is

[0019] Figure 2 Two inductor layouts of the coupling structure of the present invention

[0020] Figure 3 The traditional two-inductor circuit layout

[0021] Figure 4 The voltage gain result of the present invention is DETAILED DESCRIPTION

[0022] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be pointed out that the described embodiments are only part of the embodiments of the present invention, not all of them, and all other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention are within the protection scope of the present invention.

[0023] like Figure 1 As shown, a radio frequency receiving front-end circuit based on a coupling structure includes a receiving filter 1 and a low noise amplifier 2. The radio frequency receiving front-end circuit is connected through an input and output interface in the order of the receiving filter 1 and the low noise amplifier 2.

[0024] The receiving filter 1 includes a first parallel resonator 11, a first parallel inductor 12, a first series capacitor 13, a first series resonator 14, a second series capacitor 15, and a second series resonator 16. The first parallel resonator 11 is composed of a first inductor 111 and a first capacitor 112 in parallel, the first series resonator 14 is composed of a second inductor 141 and a second capacitor 142 in series, and the second series resonator 16 is composed of a third inductor 161 and a third capacitor 162 in series.

[0025] Preferably, the first parallel resonator 11 connects the input end of the receiving filter 1 and the first parallel inductor 12, the first series resonator 14 connects the first series capacitor 13 and the second series capacitor 15, and the second series resonator 16 connects the second series capacitor 15 and the output end of the receiving filter 1.

[0026] Preferably, the low-noise amplifier 2 includes a common-source amplifier module circuit 21 and a common-gate amplifier module circuit 22, the common-source amplifier module circuit includes a first series inductor 211, a first transistor 212, a first feed resistor 213, a first feed capacitor 214, and a first grounding inductor 215, the common-gate amplifier module circuit includes a second transistor 221, a second feed resistor 222, a second feed capacitor 223, a first output inductor 224, a second output inductor 225, and a first output capacitor 226, and the drain of the first transistor 212 of the common-source amplifier module circuit 21 is connected to the source of the second transistor 221 of the common-gate amplifier module circuit 22.

[0027] Preferably, the first series inductor 221 is connected to the input end of the low noise amplifier 2 and the first feeding resistor 213, the gate of the first transistor 212 is connected to the first feeding resistor 213, the source of the first transistor 212 is connected to the first grounding inductor 215, the drain of the first transistor 212 is connected to the source of the second transistor 221, the gate of the second transistor 221 is connected to the second feeding resistor 222, the drain of the second transistor 221 is connected to the first output inductor 224 and the second output inductor 225, and the first output capacitor 226 is connected to the second output inductor 225 and the output end of the low noise amplifier 2.

[0028] Preferably, the third inductor 161 of the receiving filter 1 and the first series inductor 221 of the low noise amplifier 1 are connected by winding coupling.

[0029] Principle of the RF receiving front-end circuit: The RF receiving front-end circuit includes a receiving filter and a low-noise amplifier, wherein the receiving front-end filter is used to filter out interference signals in the communication environment, and the first parallel resonator, the first series resonator and the second series resonator in the receiving filter will filter out interference signals in three different frequency bands. The first parallel inductor, the first series capacitor and the second series capacitor are used to achieve impedance matching of the receiving filter, wherein the low-noise amplifier will amplify the received signal and generate as little noise as possible, and the noise usually comes from the first transistor and the second transistor of the low-noise amplifier. By performing impedance matching on the low-noise amplifier through the first series inductor, the noise generated by the first transistor and the second transistor can be reduced as much as possible, and a signal amplification with a low noise coefficient can be achieved.

[0030] In the traditional RF receiving front end, due to the increase of interference frequency bands in communication, the requirements for the receiving filter of the RF receiving front end circuit become higher, and its size also increases accordingly, resulting in the size of the RF front end circuit becoming larger. The use of advanced integrated circuit manufacturing technology and multi-layer substrate technology can reduce the size of the RF front end circuit to a certain extent, but the corresponding circuit cost will increase significantly.

[0031] The present invention introduces inductive coupling between the receiving filter and the low noise amplifier. The coupling is located before the third inductor of the receiving filter and the first series inductor of the low noise amplifier. The two inductors are wound together on the layout. Figure 2 As shown, compared Figure 3 The coupled structure inductor proposed in the present invention reduces the layout size of the traditional two inductors to the layout size of one inductor, thereby reducing the circuit size and circuit cost. At the same time, since the coupling between the inductors will introduce a high-order filter impedance matching effect, the size of the receiving filter can be further reduced in design.

[0032] Example 1

[0033] The RF receiving front end operating at 3.3-4.2GHz is designed and manufactured using TSMC 65nm CMOS process technology.

[0034] A radio frequency receiving front-end circuit based on a coupling structure includes a receiving filter 1 and a low noise amplifier 2. The radio frequency receiving front-end circuit is connected in the order of the receiving filter 1 and the low noise amplifier 2 through an input and output interface. The receiving filter 1 includes a first parallel resonator 11, a first parallel inductor 12, a first series capacitor 13, a first series resonator 14, a second series capacitor 15, and a second series resonator 16. The first parallel resonator 11 is composed of a first inductor 111 and a first capacitor 112 connected in parallel. The first series resonator 14 is composed of a second inductor 141 and a second capacitor 112 connected in parallel. 42 are connected in series, the second series resonator 16 is composed of a third inductor 161 and a third capacitor 162 connected in series, the first parallel resonator 11 is connected to the input end of the receiving filter 1 and the first parallel inductor 12, the first series resonator 14 is connected to the first series capacitor 13 and the second series capacitor 15, the second series resonator 16 is connected to the second series capacitor 15 and the output end of the receiving filter 1, the low noise amplifier 2 includes a common source amplifier module circuit 21, a common gate amplifier module circuit 22, the common source amplifier module circuit includes a first series inductor 211, a first transistor 212, a first feed The common-source amplifier module circuit includes a first transistor 221, a second feeding resistor 222, a second feeding capacitor 223, a first output inductor 224, a second output inductor 225, and a first output capacitor 226. The drain of the first transistor 212 of the common-source amplifier module circuit 21 is connected to the source of the second transistor 221 of the common-gate amplifier module circuit 22. The first series inductor 221 is connected to the input end of the low-noise amplifier 2 and the first feeding resistor 213. The gate of the first transistor 212 is connected to the first The feed resistor 213, the source of the first transistor 212 is connected to the first grounded inductor 215, the drain of the first transistor 212 is connected to the source of the second transistor 221, the gate of the second transistor 221 is connected to the second feed resistor 222, the drain of the second transistor 221 is connected to the first output inductor 224 and the second output inductor 225, the first output capacitor 226 is connected to the second output inductor 225 and the output end of the low noise amplifier 2, and the third inductor 161 of the receiving filter 1 and the first series inductor 221 of the low noise amplifier 1 are connected by winding coupling.

[0035] like Figure 4As shown, it is a voltage gain curve diagram of the present invention, which shows the voltage gain amplification curve of the present invention in the frequency range of 0.5-8GHz, wherein the in-band voltage gain of 3.3-4.2GHz is greater than 19dB, and has a 60dB suppression effect on Band1 and Band3 frequency bands, a 40dB suppression effect on Band41 frequency band, and a 35dB suppression effect on the 5G WIFI frequency band.

[0036] In summary, the RF receiving front-end circuit based on the coupling structure of the present invention can effectively reduce the circuit size and reduce the circuit cost by introducing the coupling structure between the receiving filter and the low noise amplifier.

Claims

1. A radio frequency receiving front-end circuit based on a coupling structure, comprising a receiving filter, a low noise amplifier, the receiving filter, and the low noise amplifier connected in sequence through an input and output interface, characterized in that: The receiving filter comprises a first parallel resonator (11), a first parallel inductor (12), a first series capacitor (13), a first series resonator (14), a second series capacitor (15), and a second series resonator (16). The first parallel resonator (11) is formed by a first inductor (111) and a first capacitor (112) connected in parallel, the first series resonator (14) is formed by a second inductor (141) and a second capacitor (142) connected in series, and the second series resonator (16) is formed by a third inductor (161) and a third capacitor (162) connected in series.

2. The RF receiving front-end circuit based on the coupling structure according to claim 1, characterized in that: The first parallel resonator (11) is connected to the input end of the receiving filter (1) and the first parallel inductor (12), the first series resonator (14) is connected to the first series capacitor (13) and the second series capacitor (15), and the second series resonator (16) is connected to the second series capacitor (15) and the output end of the filter.

3. The RF receiving front-end circuit based on the coupling structure according to claim 1, characterized in that: The low noise amplifier (2) comprises a common-source amplifier module circuit (21) and a common-gate amplifier module circuit (22); the common-source amplifier module circuit (21) comprises a first series inductor (211), a first transistor (212), a first feed resistor (213), a first feed capacitor (214), and a first ground inductor (215); the common-gate amplifier module circuit (22) comprises a second transistor (221), a second feed resistor (222), a second feed capacitor (223), a first output inductor (224), a second output inductor (225), and a first output capacitor (226); the drain of the first transistor (212) of the common-source amplifier module circuit (21) is connected to the source of the second transistor (221) of the common-gate amplifier module circuit (22).

4. According to claim 1, the first series inductor (211) is connected to the input end of the low noise amplifier (2) and the first feeding resistor (213), the gate of the first transistor (212) is connected to the first feeding resistor (213), the source of the first transistor (212) is connected to the first grounding inductor (215), the gate of the second transistor (221) is connected to the second feeding resistor (222), the drain of the second transistor (221) is connected to the first output inductor (224) and the second output inductor (225), and the first output capacitor (226) is connected to the second output inductor (225) and the output end of the low noise amplifier (2).

5. According to claim 1, the third inductor (161) of the receiving filter (1) and the first series inductor (211) of the low noise amplifier (2) are connected by winding coupling.

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