Signal transmission circuit, amplifier and transceiver

Abstract

This application provides a signal transmission circuit, including a pre-stage load and a post-stage load; an impedance matching circuit electrically connected between the pre-stage load and the post-stage load, used to match the output impedance of the pre-stage load and the input impedance of the post-stage load; the impedance matching circuit includes a transmission line, the length of which is one-quarter of the wavelength of the transmitted signal, and the bandwidth of the impedance matching circuit is adjusted by adjusting the characteristic impedance of the transmission line. This application also provides an amplifier and a transceiver. Therefore, the signal transmission circuit, amplifier, and transceiver provided by this application can achieve impedance matching between the pre-stage load and the post-stage load by setting a one-quarter wavelength transmission line, and adjust the bandwidth of the impedance matching circuit by adjusting the characteristic impedance of the transmission line.

Description

Technical Field

[0001] This application relates to the field of communication circuits, and more particularly to a signal transmission circuit, an amplifier, and a transceiver. Background Technology

[0002] With the development of communication technology, millimeter-wave transceiver circuits have been more widely used. Millimeter-wave transceiver circuits include impedance matching circuits, which are used to match the impedance of millimeter-wave signals to improve their transmission performance and reduce transmission loss. However, the bandwidth of existing impedance matching circuits is insufficient and cannot cover the frequency range of millimeter-wave signals. Summary of the Invention

[0003] In view of the above problems, this application provides a signal transmission circuit, amplifier, and transceiver that can achieve impedance matching between the front-end load and the back-end load by setting a quarter-wavelength transmission line, and adjust the bandwidth of the impedance matching circuit by adjusting the characteristic impedance of the transmission line.

[0004] In a first aspect, this application provides a signal transmission circuit, including: a pre-stage load and a post-stage load; an impedance matching circuit electrically connected between the pre-stage load and the post-stage load, the impedance matching circuit being used to perform impedance matching on the output impedance of the pre-stage load and the input impedance of the post-stage load; the impedance matching circuit includes a transmission line, the length of which is one-quarter of the wavelength of the transmitted signal, and the bandwidth of the impedance matching circuit is adjusted by adjusting the characteristic impedance of the transmission line.

[0005] In some possible implementations, the impedance matching circuit includes a first inductor, a first capacitor, and a second capacitor. The first inductor is electrically connected between the preceding load and the following load, the first capacitor is electrically connected between the first terminal of the first inductor and ground, and the second capacitor is electrically connected between the second terminal of the first inductor and ground.

[0006] In some possible implementations, the total characteristic impedance of the first inductor, the first capacitor, and the second capacitor is the square root of the product of the resistance values ​​of the preceding load and the following load.

[0007] In some possible implementations, the impedance matching circuit includes a second inductor, a third inductor, and a third capacitor. The first end of the second inductor is electrically connected to the preceding load, the second end of the second inductor is electrically connected to the first end of the third inductor and the first end of the second capacitor, and the second end of the second inductor is electrically connected to the following load.

[0008] In some possible implementations, the total characteristic impedance of the second inductor, the third inductor, and the third capacitor is the square root of the product of the resistance values ​​of the preceding load and the following load.

[0009] In some possible implementations, the impedance matching circuit includes a fourth capacitor, a fourth inductor, and a fifth inductor. The first capacitor is electrically connected between the preceding load and the following load. The fourth inductor is electrically connected between the first terminal of the first capacitor and ground. The fifth inductor is electrically connected between the second terminal of the first capacitor and ground. The total characteristic impedance of the fourth capacitor, the fourth inductor, and the fifth inductor is the square root of the product of the resistance values ​​of the preceding load and the following load.

[0010] In some possible implementations, the impedance matching circuit includes a fifth capacitor, a sixth capacitor, and a sixth inductor. The first terminal of the fifth capacitor is electrically connected to the preceding load, the second terminal of the fifth capacitor is electrically connected to the first terminal of the sixth capacitor and the first terminal of the sixth inductor, and the second terminal of the sixth capacitor is electrically connected to the following load. The total characteristic impedance of the fifth capacitor, the sixth capacitor, and the sixth inductor is the square root of the product of the resistance values ​​of the preceding load and the following load.

[0011] In some possible implementations, the impedance matching circuit includes a transformer, the primary coil of which is electrically connected to the preceding load and the secondary coil of which is electrically connected to the following load. The characteristic impedance of the transformer is the square root of the product of the resistance values ​​of the preceding and following loads.

[0012] Secondly, this application provides an amplifier including the signal transmission circuit described above.

[0013] Thirdly, this application provides a transceiver, including a receiver or a transmitter, and the transceiver includes the aforementioned amplifier.

[0014] Therefore, the signal transmission circuit, amplifier, and transceiver provided in this application can achieve impedance matching between the front-end load and the back-end load by setting a quarter-wavelength transmission line, and adjust the bandwidth of the impedance matching circuit by adjusting the characteristic impedance of the transmission line. Attached Figure Description

[0015] Figure 1 A structural diagram of the signal transmission circuit provided in this application.

[0016] Figures 2A to 2C A circuit diagram of an impedance matching circuit provided for one embodiment of this application.

[0017] Figure 3 A circuit diagram of an impedance matching circuit provided for another embodiment of this application.

[0018] Figure 4 A to Figure 4 D is the equivalent circuit diagram of a quarter-wavelength transmission line provided in this application.

[0019] Figure 5 This is a schematic diagram of replacing a quarter-wavelength transmission line with an impedance matching circuit.

[0020] Figure 6 This is a schematic diagram of replacing a quarter-wavelength transmission line with another impedance matching circuit.

[0021] Figure 7 This is a schematic diagram of replacing a quarter-wavelength transmission line with another impedance matching circuit.

[0022] Explanation of main component symbols

[0023] Signal transmission circuit 10

[0024] Front-end load 11 12, 121, 122, 123, 124

[0026] Impedance matching circuits 1241, 1242, 1243, 1244, 1252

[0028] Post-stage load 13

[0029] Resistors R1, R2, RW, RL

[0030] Capacitors C, C1, C2, Cc1, Cc2, C'

[0031] Inductors L, L1, L2, L11, L21

[0032] Transformers T1, TX, TX0, TX1

[0033] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0034] In the embodiments of this application, terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or order. For example, "first application" and "second application" are used to distinguish different applications, not to describe a specific order of applications. Features specified as "first" or "second" may explicitly or implicitly include one or more of those features.

[0035] Please see Figure 1 This is a structural diagram of the signal transmission circuit 10 provided in this application. The signal transmission circuit 10 includes a pre-stage load 11, a post-stage load 13, and an impedance matching circuit 12. The impedance matching circuit 12 is electrically connected between the pre-stage load 11 and the post-stage load 13. The impedance matching circuit 12 is used to perform impedance matching between the pre-stage load 11 and the post-stage load 13 to improve signal transmission performance and reduce signal transmission loss.

[0036] It is understood that the signal transmission circuit 10 can be set in the amplifier to process the input signal of the amplifier. The amplifier can be set in the transceiver, which includes a receiver or a transmitter to receive or transmit the signal amplified by the amplifier.

[0037] The preamplifier load 11 receives the input signal through nodes IN1 and IN2. It can be understood that the input signal can power the preamplifier load 11. In some possible implementations, the impedance of the preamplifier load 11 can be equivalent to the parallel impedance of resistor R1 and capacitor C1, that is, the output impedance of the preamplifier load 11 is Zout.

[0038] The downstream load 13 transmits its output signal through nodes OUT1 and OUT2. This output signal can be understood as powering the downstream load 13. In some possible implementations, the impedance of the downstream load 13 can be equivalent to the parallel impedance of resistor R2 and capacitor C2, meaning the input impedance of the downstream load 13 is Zin.

[0039] It is understood that the impedance matching circuit 12 may include capacitors, inductors or resistors to perform impedance matching on the output impedance Zout of the preceding load 11 and the input impedance Zin of the following load 13.

[0040] Please see Figures 2A to 2C These are circuit diagrams of impedance matching circuit 121, impedance matching circuit 122, and impedance matching circuit 123 provided in an embodiment of this application.

[0041] like Figure 2A As shown, the impedance matching circuit 121 includes capacitors Cc1 and Cc2, inductor L1 and inductor L2. Capacitors Cc1 and Cc2 are both electrically connected between the front-end load 11 and the rear-end load 13. Inductor L1 is electrically connected to the first end of capacitor Cc1 and the first end of capacitor Cc2, and inductor L2 is electrically connected to the second end of capacitor Cc1 and the second end of capacitor Cc2.

[0042] It is understood that the signal transmission impedance can be adjusted by adjusting the capacitance values ​​of capacitors Cc1 and Cc2, or the inductance values ​​of inductors L1 and L2, thereby achieving impedance matching between the front-end load 11 and the back-end load 13.

[0043] like Figure 2B As shown, the impedance matching circuit 122 includes a transformer T1 with a coupling coefficient of k. The primary coil of the transformer T1 is electrically connected to the two ends of the preceding load 11, and the secondary coil of the transformer T1 is electrically connected to the two ends of the following load 13.

[0044] It is understandable that transformer T1 isolates the preceding load 11 from the following load 13, thereby improving the isolation performance of signal transmission. Since transformer T1 includes a coil (essentially an inductor), the signal transmission impedance can also be adjusted by changing the inductance value of transformer T1, thus achieving impedance matching between the preceding load 11 and the following load 13.

[0045] like Figure 2C As shown, the impedance matching circuit 123 includes capacitor Cc1, capacitor Cc2, and transformer T1. Both capacitor Cc1 and capacitor Cc2 are electrically connected between the front-end load 11 and the rear-end load 13. The coupling coefficient of transformer T1 is k. The primary coil of transformer T1 is electrically connected to both ends of the front-end load 11, and the secondary coil of transformer T1 is electrically connected to both ends of the rear-end load 13.

[0046] It is understandable that the impedance of the signal transmission can be adjusted by adjusting the capacitance values ​​of capacitors Cc1 and Cc2, or the inductance value of transformer T1, so as to achieve impedance matching between the front-end load 11 and the back-end load 13.

[0047] Please see Figure 3 The following is a circuit diagram of an impedance matching circuit 124 provided in another embodiment of this application. The impedance matching circuit 124 includes a resistor RW, an inductor L1 and an inductor L2. The inductor L1 is electrically connected to node A and the first terminal of capacitor C1, and the inductor L2 is electrically connected to node A and the second terminal of capacitor C2.

[0048] It should be noted that resistor RW is the equivalent resistance value of the transmission line segment from node A to node B. Optionally, the length of the transmission line segment from node A to node B is one-quarter wavelength of the transmitted signal. A one-quarter wavelength transmission line has impedance transformation characteristics. Specifically, when a one-quarter wavelength transmission line with characteristic impedance Z0 is connected to a purely resistive load (e.g., resistor R2), the input impedance of the purely resistive load is... In other words, the characteristic impedance is A quarter-wavelength transmission line can achieve impedance matching between purely resistive loads R1 and R2.

[0049] Inductor L1 is used to cancel the equivalent capacitive reactance of capacitor C1 in the preceding stage load 11, and inductor L2 is used to cancel the equivalent capacitive reactance of capacitor C2 in the following stage load 13. Therefore, the output impedance of the preceding stage load 11 and the input impedance of the following stage load 13 are purely resistive, and their characteristic impedances are... A quarter-wavelength transmission line can achieve impedance matching between the pre-amplifier load 11 and the post-amplifier load 13.

[0050] It is understandable that the characteristic impedance of a quarter-wavelength transmission line can be adjusted according to the actual situation. When the characteristic impedance is larger, the bandwidth of the impedance matching circuit 124 is smaller, and when the characteristic impedance is smaller, the in-band ripple of the impedance matching circuit 124 is larger. Therefore, the characteristic impedance can be adjusted adaptively to balance the bandwidth and in-band ripple of the impedance matching circuit 124.

[0051] Alternatively, a quarter-wavelength transmission line can also be equivalent to, for example... Figure 4 A to Figure 4 The circuit shown in D. Specifically, as... Figure 4 As shown in Figure A, a quarter-wavelength transmission line can be equivalent to an impedance matching circuit 1241. The impedance matching circuit 1241 includes an inductor L and two capacitors C. The inductor L is electrically connected between the preceding load 11 and the following load 13. The two capacitors C are electrically connected to the first and second terminals of the inductor L, respectively. It can be understood that the characteristic impedance of the impedance matching circuit 1241 is the same as that of the quarter-wavelength transmission line. That is, the total characteristic impedance of the inductor L and the two capacitors C is Optionally, the capacitance values ​​of the two capacitors C can be different.

[0052] like Figure 4 As shown in Figure B, a quarter-wavelength transmission line can be equivalent to an impedance matching circuit 1242. The impedance matching circuit 1242 includes two inductors L and a capacitor C. The two inductors L are connected in series between the preceding load 11 and the following load 13. The first terminal of the capacitor C is electrically connected between the two inductors L, and the second terminal of the capacitor C is grounded. It can be understood that the characteristic impedance of the impedance matching circuit 1242 is the same as that of the quarter-wavelength transmission line. That is, the total characteristic impedance of the two inductors L and the capacitor C is

[0053] Impedance matching circuits 1242 and 1243 operate at low frequencies of the transmitted signal, which can cause a 90° phase shift in the transmitted signal.

[0054] like Figure 4 As shown in Figure C, a quarter-wavelength transmission line can be equivalent to an impedance matching circuit 1243. The impedance matching circuit 1243 includes two inductors L and a capacitor C. Capacitor C is electrically connected between the preceding load 11 and the following load 13. The two inductors L are respectively electrically connected to the first and second terminals of capacitor C. It can be understood that the characteristic impedance of the impedance matching circuit 1243 is the same as that of the quarter-wavelength transmission line. That is, the total characteristic impedance of the two inductors L and the capacitor C is

[0055] like Figure 4As shown in Figure D, a quarter-wavelength transmission line can be equivalent to an impedance matching circuit 1244. Impedance matching circuit 1244 includes two capacitors (C and D) and an inductor L. Two capacitors (C) are connected in series between the preceding load 11 and the following load 13. The first terminal of inductor L is electrically connected between the two capacitors (C), and the second terminal of inductor L is grounded. It can be understood that the characteristic impedance of impedance matching circuit 1244 is the same as that of a quarter-wavelength transmission line. That is, the total characteristic impedance of the two capacitors C and the inductor L is

[0056] Impedance matching circuits 1243 and 1244 operate at high frequencies of the transmitted signal, which can cause a -90° phase shift in the transmitted signal.

[0057] Please see Figure 5 This is a schematic diagram of replacing a quarter-wavelength transmission line with an impedance matching circuit 1243. It can be understood that after replacing the quarter-wavelength transmission line with the impedance matching circuit 1243, the inductor L in the impedance matching circuit 1243 can be combined with inductor L1 to form inductor L11, and the inductance value of inductor L11 is the total parallel inductance value of inductors L and L1.

[0058] In this embodiment, the s-transformation of the transresistance Z21 between the front-stage load 11 and the rear-stage load 13 satisfies formula (1):

[0059]

[0060] Wherein, ω1 is the resonant frequency of the pre-stage load 11, ω2 is the resonant frequency of the post-stage load 13, Q1 is the quality factor of the pre-stage load 11, and Q2 is the quality factor of the post-stage load 13.

[0061] If ω1=ω2=ω0, then formula (1) can be simplified to formula (2):

[0062]

[0063] From formula (2), we can see that the transresistance Z21 has two poles in the s-domain, namely ωL and ωH, where ωL =

[0064]

[0065] It can be understood that when the characteristic impedance Z0 is larger, the poles ωL and ωH are closer, that is, the bandwidth of the impedance matching circuit 1243 is smaller. When the characteristic impedance Z0 is smaller, the poles ωL and ωH are farther apart, that is, the bandwidth of the impedance matching circuit 1243 is larger.

[0066] Please see Figure 6This is a schematic diagram of replacing a quarter-wavelength transmission line with an impedance matching circuit 1241. It can be understood that after replacing the quarter-wavelength transmission line with the impedance matching circuit 1241, inductors L, L1, and L2 can be equivalent to transformer TX. The primary coil inductance Lp, secondary coil inductance Ls, and coupling coefficient k of transformer TX respectively satisfy formula (3):

[0067]

[0068] In this embodiment, the s-transformation of the transresistance Z21 between the front-stage load 11 and the rear-stage load 13 satisfies formula (4):

[0069]

[0070] Wherein, ω1 is the resonant frequency of the pre-stage load 11, ω2 is the resonant frequency of the post-stage load 13, Q1 is the quality factor of the pre-stage load 11, and Q2 is the quality factor of the post-stage load 13.

[0071] If ω1=ω2=ω0, then formula (4) can be simplified to formula (5):

[0072]

[0073] From formula (5), we can see that the transresistance Z21 has two poles in the s-domain, namely ωL and ωH, where ωL =

[0074] ω0 is the operating frequency of the impedance matching circuit 1241.

[0075] It can be understood that when the characteristic impedance Z0 is larger, the poles ωL and ωH are closer, that is, the bandwidth of the impedance matching circuit 1244 is smaller. When the characteristic impedance Z0 is smaller, the poles ωL and ωH are farther apart, that is, the bandwidth of the impedance matching circuit 1244 is larger.

[0076] Please see Figure 7 This is a schematic diagram of replacing a quarter-wavelength transmission line with an impedance matching circuit 1252. Specifically, the impedance matching circuit 1252 can be used to perform impedance matching on input or output signals (i.e., the impedance matching circuit 1252 can be applied to input impedance matching or output impedance matching), and the resistor RL is the input load or output load.

[0077] In this embodiment, the quarter-wavelength transmission line is first replaced with an impedance matching circuit 1243, and then a transformer TX0 is inserted between the impedance matching circuit 1243 and the subsequent load 13. The turns ratio of the transformer TX0 is 1:(n / k). At this time, the characteristic impedance of the impedance matching circuit 1243 becomes The impedance of capacitor C becomes C', and the impedance of inductor L becomes L'. Then, the inductance L1 between transformer TX0 and the subsequent load 13 is equivalent to that between transformer TX0 and the preceding load 11, and the capacitance C1 between transformer TX0 and the preceding load 11 is equivalent to that between transformer TX0 and the subsequent load 13. After equivalence, the impedance of inductor L1 becomes (k / n). 2 The impedance of capacitor C1 becomes (k / n) 2 C', finally, inductor L (equivalent impedance is L') and inductor L1 (equivalent impedance is (k / n)). 2 L1) and transformer TX0 are equivalent to transformer TXk, where the impedance L' of inductor L, the primary coil inductance Lp of transformer TXk, and the secondary coil impedance n of transformer TXk are all represented by L'. 2 Lp satisfies formula (6):

[0078]

[0079] This application also provides an amplifier, including a signal transmission circuit 10. The amplifier can be disposed in a transceiver, which includes a receiver or a transmitter to receive or transmit a signal amplified by the amplifier.

[0080] It is understood that the signal transmission circuit, signal transmission circuit, amplifier, and transceiver provided in this application have a simple structure, small electronic component area, and can balance the signal bandwidth and in-band ripple of the impedance matching circuit.

[0081] Those skilled in the art should recognize that the above embodiments are only used to illustrate this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application fall within the scope of protection claimed in this application.

Claims

1. A signal transmission circuit, characterized in that, include: Front-end load and back-end load; An impedance matching circuit is electrically connected between the pre-stage load and the post-stage load. The impedance matching circuit is used to perform impedance matching on the output impedance of the pre-stage load and the input impedance of the post-stage load. The impedance matching circuit includes a transmission line with a length of one-quarter of the wavelength of the transmitted signal, the transmission line being equivalent to a passive network; the passive network includes inductors and capacitors, or includes a transformer; and, while maintaining the electrical length of the transmission line at one-quarter of the wavelength, the characteristic impedance of the transmission line is changed by adjusting the parameters of the passive network to balance the bandwidth and in-band ripple of the impedance matching circuit.

2. The signal transmission circuit as described in claim 1, characterized in that, The passive network includes a first inductor, a first capacitor, and a second capacitor. The first inductor is electrically connected between the front-end load and the rear-end load. The first capacitor is electrically connected between a first terminal of the first inductor and ground. The second capacitor is electrically connected between a second terminal of the first inductor and ground.

3. The signal transmission circuit as described in claim 2, characterized in that, The total characteristic impedance of the first inductor, the first capacitor, and the second capacitor is the square root of the product of the resistance values ​​of the preceding load and the following load.

4. The signal transmission circuit as described in claim 1, characterized in that, The passive network includes a second inductor, a third inductor, and a third capacitor. The first end of the second inductor is electrically connected to the preceding load. The second end of the second inductor is electrically connected to the first end of the third inductor and the first end of the third capacitor. The second end of the third inductor is electrically connected to the following load. The second end of the third capacitor is grounded.

5. The signal transmission circuit as described in claim 4, characterized in that, The total characteristic impedance of the second inductor, the third inductor, and the third capacitor is the square root of the product of the resistance values ​​of the preceding load and the following load.

6. The signal transmission circuit as described in claim 1, characterized in that, The passive network includes a fourth capacitor, a fourth inductor, and a fifth inductor. The fourth capacitor is electrically connected between the pre-stage load and the post-stage load. The fourth inductor is electrically connected between the first terminal of the fourth capacitor and ground. The fifth inductor is electrically connected between the second terminal of the fourth capacitor and ground. The total characteristic impedance of the fourth capacitor, the fourth inductor, and the fifth inductor is the square root of the product of the resistance values ​​of the pre-stage load and the post-stage load.

7. The signal transmission circuit as described in claim 1, characterized in that, The passive network includes a fifth capacitor, a sixth capacitor, and a sixth inductor. The first terminal of the fifth capacitor is electrically connected to the preceding load. The second terminal of the fifth capacitor is electrically connected to the first terminal of the sixth capacitor and the first terminal of the sixth inductor. The second terminal of the sixth capacitor is electrically connected to the following load. The second terminal of the sixth inductor is grounded. The total characteristic impedance of the fifth capacitor, the sixth capacitor, and the sixth inductor is the square root of the product of the resistance values ​​of the preceding load and the following load.

8. The signal transmission circuit as described in claim 1, characterized in that, The passive network includes a transformer, the primary coil of which is electrically connected to the preceding load, and the secondary coil of which is electrically connected to the following load. The characteristic impedance of the transformer is the square root of the product of the resistance values ​​of the preceding load and the following load.

9. An amplifier, characterized in that, Includes the signal transmission circuit as described in any one of claims 1-8.

10. A transceiver, comprising a receiver or a transmitter, characterized in that, The transceiver includes the amplifier as described in claim 9.

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