Mixer and signal transmission equipment

Abstract

The invention provides a frequency mixer and signal transmission equipment, and belongs to the technical field of communication. In the scheme provided by the invention, the mixer can transmit the local oscillator signal through the slot line, and transmit the first signal, the second signal and the third signal through the microstrip line. Therefore, it can be ensured that the transmission mode of the local oscillator signal is different from the transmission mode of the first signal and is different from the transmission modes of the second signal and the third signal, that is, the transmission mode isolation of the local oscillator signal from the first signal and the transmission mode isolation of the local oscillator signal from the second signal and the third signal can be realized. The transmission modes of the local oscillator signal and other signals are isolated, so that the leakage of the local oscillator signal at other signal ports can be effectively reduced, and the performance of the mixer is effectively improved.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a mixer and a signal transmission device. Background Art

[0002] The mixer is a key component used for frequency conversion in microwave systems. In a receiver, the mixer can mix the received RF signal and the local oscillator signal to obtain an intermediate frequency signal or a baseband signal. In a transmitter, the mixer can mix the baseband signal (or intermediate frequency signal) and the local oscillator signal to obtain an RF signal.

[0003] However, in the process of mixing signals of different frequencies, the local oscillator signal may leak to other signal ports of the mixer, such as the RF signal port. That is, the mixer may have the problem of local oscillator signal leakage (abbreviated as local oscillator leakage). This local oscillator leakage will seriously affect the performance of the receiver and transmitter. Summary of the invention

[0004] The present application provides a mixer and a signal transmission device, which can solve the technical problem of serious local oscillator leakage of the mixer in the related art.

[0005] In a first aspect, a mixer is provided, which includes: a core circuit, a slot line, a first microstrip line, a second microstrip line and a third microstrip line. The slot line, the first microstrip line, the second microstrip line and the third microstrip line are all connected to the core circuit. The slot line is used to transmit a local oscillator signal to the core circuit, the first microstrip line is used to transmit a first signal of a first frequency, the second microstrip line is used to transmit a second signal of a second frequency, and the third microstrip line is used to transmit a third signal of a second frequency. The second frequency is different from the first frequency, and the third signal has an opposite phase to the second signal. The core circuit is used to realize frequency conversion between the first frequency and the second frequency based on the local oscillator signal.

[0006] The mixer provided by the present application can transmit the local oscillator signal through the slot line, and transmit the first signal and the second signal through the microstrip line. Thus, it can be ensured that the transmission mode of the local oscillator signal is different from the transmission mode of the first signal, and different from the transmission modes of the second signal and the third signal, that is, the transmission mode isolation of the local oscillator signal from the first signal, and the transmission mode isolation from the second signal and the third signal can be achieved. Since the transmission mode of the local oscillator signal is isolated from that of other signals, the leakage of the local oscillator signal at other signal ports can be effectively reduced, thereby effectively improving the performance of the mixer.

[0007] Optionally, the core circuit may include: a first transistor and a second transistor, wherein the first electrode of the first transistor is connected to the first electrode of the second transistor. One side of the slot line is connected to the gate of the first transistor, and the other side of the slot line is connected to the gate of the second transistor. The first microstrip line is connected to the first electrode of the first transistor, the second microstrip line is connected to the second electrode of the first transistor, and the third microstrip line is connected to the second electrode of the second transistor.

[0008] It is understood that the slot line is composed of two spaced metal plates (or metal wires), one side of the slot line refers to one of the metal plates (or metal wires), and the other side of the slot line refers to the other metal plate (or metal wire). It is also understood that the first electrode of the transistor can be one of the source and the drain, and the second electrode can be the other of the source and the drain.

[0009] The two sides of the slot line are connected to the gates of the two transistors, which can realize the differential feeding of the local oscillator signal, that is, the local oscillator signal fed into the core circuit is a differential signal. The gate double-feed structure can ensure that even if the local oscillator signal leaks to other signal ports of the mixer (such as the RF signal port), the leaked signal phase is opposite and the energy is offset, thereby effectively improving the local oscillator suppression.

[0010] Optionally, the first transistor and the second transistor may both be field effect transistors. Using field effect transistors as nonlinear units of the mixer can ensure high linearity.

[0011] The field effect transistor may be a transistor with high electron mobility and low knee voltage, so as to further ensure that the frequency conversion efficiency and linearity of the mixer are both high.

[0012] Optionally, the groove line, the gate of the first transistor, and the gate of the second transistor may all be located in the same layer and may be made of the same metal material, thereby effectively simplifying the preparation process of the mixer and improving the preparation efficiency of the mixer.

[0013] Optionally, the strip conductor of the first microstrip line, the strip conductor of the second microstrip line, the strip conductor of the third microstrip line, the first pole and the second pole of the first transistor, and the first pole and the second pole of the second transistor can all be located in the same layer and can be made of the same metal material.

[0014] It is understandable that the microstrip line may include a strip conductor located on top of a dielectric substrate and a ground (GND) plane located below the dielectric substrate. In the solution provided in the present application, the slot line, the strip conductors of each microstrip line, and each electrode of the transistor may be located in the same layer and may be made of the same metal material. Thus, the preparation process of the mixer can be effectively simplified and the preparation efficiency of the mixer can be improved.

[0015] Optionally, the mixer may further include: a fourth microstrip line; the fourth microstrip line is connected to the slot line and is used to transmit a local oscillator signal to the slot line. The local oscillator signal transmitted by the fourth microstrip line may be a single-ended signal, which may be converted into a differential signal after being fed into the slot line. That is, the transmission mode of the local oscillator signal may be converted from the main transmission mode of the microstrip line to the main transmission mode of the slot line, thereby realizing a change in the electromagnetic field transmission mode.

[0016] Optionally, the slot line may also be directly connected to the local oscillator port and used to receive the local oscillator signal output by the local oscillator port. The local oscillator signal output by the local oscillator port is a differential signal.

[0017] By directly feeding in a differential local oscillator signal, there is no need to transmit the local oscillator signal from the microstrip line to the slot line and convert the signal transmission mode, which can effectively simplify the structure of the mixer.

[0018] Optionally, the first signal may be a radio frequency signal, and the second signal and the third signal may both be intermediate frequency signals; or, the first signal may be an intermediate frequency signal, and the second signal and the third signal may both be radio frequency signals. Accordingly, the mixer can realize frequency conversion between the radio frequency signal and the intermediate frequency signal. Among them, the intermediate frequency signal may also include a zero intermediate frequency signal, that is, a baseband signal. That is, the mixer can be applied to a zero intermediate frequency architecture.

[0019] Optionally, the first microstrip line can be used to transmit a first signal to the core circuit, the second microstrip line is used to transmit a second signal output by the core circuit, and the third microstrip line is used to transmit a third signal output by the core circuit. That is, the first signal can be an input signal, and the second signal and the third signal can both be output signals.

[0020] Alternatively, the first microstrip line is used to transmit the first signal output by the core circuit, the second microstrip line is used to transmit the second signal to the core circuit, and the third microstrip line is used to transmit the third signal to the core circuit. That is, the second signal and the third signal can both be input signals, and the first signal can be an output signal.

[0021] It is understandable that if the RF signal is the input signal and the IF signal is the output signal, the mixer is used to down-convert the RF signal, that is, the mixer can work as a down-converter. At this time, the input RF signal can drive the transistor in the core circuit of the mixer to generate a channel current.

[0022] If the intermediate frequency signal is the input signal and the radio frequency signal is the output signal, the mixer is used to up-convert the intermediate frequency signal, that is, the mixer can work as an up-converter. At this time, the input intermediate frequency signal can drive the transistor in the core circuit of the mixer to generate a channel current.

[0023] Optionally, the mixer may further include: at least one of a first frequency selection circuit, a second frequency selection circuit, a third frequency selection circuit, and a fourth frequency selection circuit, wherein the first frequency selection circuit is connected to the slot line, the second frequency selection circuit is connected to the first microstrip line, the third frequency selection circuit is connected to the second microstrip line, and the fourth frequency selection circuit is connected to the third microstrip line.

[0024] If the mixer includes a fourth microstrip line, the first frequency selection circuit can be connected to the slot line through the fourth microstrip line. The first frequency selection circuit can achieve matching of the local oscillator signal and open circuit of the first signal, the second signal and the third signal. The second frequency selection circuit can achieve matching of the first signal, open circuit of the local oscillator signal, and short circuit of the second signal and the third signal. The third frequency selection circuit and the fourth frequency selection circuit can achieve matching of the second signal and the third signal, open circuit of the local oscillator signal, and short circuit of the first signal.

[0025] In the solution provided by the present application, since the local oscillator signal is isolated from the transmission mode of the first signal, and is isolated from the transmission modes of the second signal and the third signal, the complexity of matching each signal port of the mixer can be effectively reduced, so that each signal port does not need to adopt a frequency selection circuit with a high suppression ratio. As a result, the structural complexity and area of ​​each frequency selection circuit can be effectively reduced, thereby saving the chip area and cost of the mixer. For example, compared with using a microstrip line to transmit the local oscillator signal, the first signal, the second signal and the third signal, the area and cost of the mixer provided in the embodiment of the present application can be saved by about 30%.

[0026] In a second aspect, a signal transmission device is provided, which may include: an antenna, and a mixer as provided in the first aspect. The mixer is used to perform frequency conversion on a signal received by the antenna, and / or the mixer is used to transmit the frequency-converted signal to the antenna and radiate it through the antenna.

[0027] Among them, if the mixer is an up-converter, it can up-convert the baseband signal or the intermediate frequency signal into a radio frequency signal, and transmit the radio frequency signal to the antenna for antenna radiation. If the mixer is a down-converter, it can down-convert the radio frequency signal received by the antenna into an intermediate frequency signal or a baseband signal. Since the mixer provided in the above aspects can effectively suppress the leakage of the local oscillator signal, it can ensure that the signal transmission performance of the signal transmission device is good.

[0028] In summary, the present application provides a mixer and a signal transmission device, which can transmit a local oscillator signal through a slot line, and transmit a second signal and a third signal through a microstrip line. In this way, it can be ensured that the transmission mode of the local oscillator signal is different from the transmission mode of the first signal, and different from the transmission modes of the second signal and the third signal, that is, the transmission mode isolation of the local oscillator signal from the first signal, and the transmission mode isolation from the second signal and the third signal can be achieved. Since the electromagnetic field signal transmission mode of the local oscillator signal is isolated from that of other signals, the leakage of the local oscillator signal at other signal ports can be effectively reduced, thereby effectively improving the performance of the mixer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a signal transmission device provided in an embodiment of the present application;

[0030] Figure 2 is a structural schematic diagram of a mixer provided in an embodiment of the present application;

[0031] Figure 3 is a schematic diagram of a transmission mode of each signal in a mixer provided in an embodiment of the present application;

[0032] Figure 4 is a structural schematic diagram of a core circuit of a mixer provided in an embodiment of the present application;

[0033] Figure 5 is a schematic structural diagram of another mixer provided in an embodiment of the present application;

[0034] Figure 6 It is a structural schematic diagram of another mixer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The mixer and signal transmission device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0036] The mixer provided in the embodiment of the present application can be applied to a signal transmission device, which can be used to transmit microwave signals and can therefore also be referred to as a microwave transmission device. For example, the signal transmission device can be used to transmit radio frequency signals, that is, the signal transmission device can be a radio frequency receiver, a radio frequency transmitter, or a radio frequency transceiver.

[0037] Figure 1 is a schematic diagram of a structure of a signal transmission device provided in an embodiment of the present application, and Figure 1 The signal transmission device is a radio frequency transceiver device. Figure 1As shown, the signal transmission device may include: an antenna 01, a receiving link 02 and a transmitting link 03. Among them, the receiving link 02 may include: an amplifier 021, a filter 022, a mixer 023 and an analog to digital converter (ADC) 024. The amplifier 021 may be a low noise amplifier (LNA), which is used to amplify the radio frequency (RF) signal received by the antenna 01. The filter 022 is used to filter the radio frequency signal. The mixer 023 is used to down-convert the radio frequency signal based on the local oscillator (LO) signal to obtain an intermediate frequency (IF) signal or a baseband signal. The ADC 024 is used to perform analog-to-digital conversion on the analog signal output by the mixer 023 to obtain a digital signal, and transmit the converted digital signal to the baseband chip (not shown in the figure).

[0038] Continue to refer Figure 1 , the transmission chain 03 may include an amplifier 031, a filter 032, a mixer 033 and a digital to analog converter (DAC) 034. Among them, DAC 034 is used to perform digital-to-analog conversion on the digital baseband signal to be transmitted by the baseband chip to obtain an analog baseband signal. The mixer 033 is used to up-convert the analog baseband signal based on the local oscillator signal to obtain a radio frequency signal. The filter 032 is used to filter the radio frequency signal. The amplifier 031 can be a power amplifier (PA), which is used to amplify the power of the received radio frequency signal and transmit the power-amplified radio frequency signal to the antenna 01. The antenna 01 can then radiate the received radio frequency signal.

[0039] The antenna 01 may include a receiving antenna and a transmitting antenna. The receiving antenna is connected to the receiving link 02 and is used to receive radio frequency signals transmitted by other devices. The transmitting antenna is connected to the transmitting link 03 and is used to radiate radio frequency signals into space.

[0040] It can be understood that the signal transmission device provided in the embodiment of the present application can be a signal receiving device (also called a receiver), and accordingly, the signal transmission device may not include the transmission link 03. Alternatively, the signal transmission device provided in the embodiment of the present application can be a signal transmitting device (also called a transmitter), and accordingly, the signal transmission device may not include the receiving link 02.

[0041] It can also be understood that the receiving link 02 and / or the transmitting link 03 in the signal transmission device may also include other signal processing devices, for example, a larger number of amplifiers, filters and / or mixers. Of course, the signal processing devices included in the receiving link 02 and / or the transmitting link 03 may also be reduced according to the requirements of the application scenario, and the connection relationship between the signal processing devices may also be flexibly adjusted according to the requirements of the application scenario, which is not limited in the embodiments of the present application.

[0042] For example, if the signal transmission device adopts a zero intermediate frequency architecture, the mixer 023 and the mixer 033 can realize the frequency conversion between the radio frequency signal and the baseband signal. If the signal transmission device adopts a superheterodyne architecture, the receiving link 02 and the transmitting link 03 can each include at least two mixers, one of which can be used to realize the frequency conversion between the radio frequency signal and the intermediate frequency signal, and the other mixer can be used to realize the frequency conversion between the intermediate frequency signal and the baseband signal.

[0043] For the receiving link, if a zero intermediate frequency architecture is used, in the scenario of 1+1 module hot backup, the local oscillator signal of the backup module may be fed to the receiving end of the working module through the combining unit, causing co-frequency interference, thereby affecting the sensitivity of the receiver. Among them, 1+1 module hot backup can refer to deploying a main receiver and a backup receiver in the system. The backup module can refer to the backup receiver, and the working module can refer to the main receiver.

[0044] In the transmission link, the leakage of the local oscillator signal will affect the accuracy of the transmission detection power, and additional orthogonal modulation compensation (QMC) algorithm correction or equipment correction is required to improve the performance of the device. Based on the above analysis, it can be seen that the hardware implementation solution to reduce or suppress the leakage of the local oscillator signal is very important for improving the performance of signal transmission equipment.

[0045] The image rejection mixer in the related art can achieve 180-degree reverse cancellation of two image signals through two 90-degree bridges of radio frequency and intermediate frequency. Although the image rejection mixer can suppress the image frequency interference energy, it cannot suppress the local oscillator leakage.

[0046] The LO rejection mixer in the related art can achieve the LO power energy cancellation at the RF port by 180-degree phase shift of the LO signal, and provide an additional LO signal suppression function. However, the core circuit of the LO rejection mixer does not have the LO signal suppression function, and cannot effectively suppress the leakage of the LO signal.

[0047] The core circuit of the mixer refers to a nonlinear circuit in the mixer for realizing frequency conversion, and the nonlinear circuit may include one or more nonlinear elements. The area where the core circuit is located may also be called a core area.

[0048] Figure 2 is a schematic diagram of a structure of a mixer provided in an embodiment of the present application. The mixer can be applied to, for example, Figure 1 In the signal transmission device shown. For example, the mixer can be used to mix the local oscillator signal and the radio frequency signal to obtain an intermediate frequency signal; or, the mixer can be used to mix the local oscillator signal and the intermediate frequency signal to obtain a radio frequency signal. The mixer provided in the embodiment of the present application can effectively reduce the leakage of the local oscillator signal and improve the performance of the device.

[0049] like Figure 2 As shown, the mixer may include: a core circuit 10, a slot line 20, a first microstrip line 30, a second microstrip line 40 and a third microstrip line 50. The slot line 20, the first microstrip line 30, the second microstrip line 40 and the third microstrip line 50 are all connected to the core circuit 10.

[0050] In the embodiment of the present application, the slot line 20 can be used to transmit a local oscillator signal to the core circuit 10, the first microstrip line 30 can be used to transmit a first signal of a first frequency, the second microstrip line 40 can be used to transmit a second signal of a second frequency, and the third microstrip line 50 can be used to transmit a third signal of the second frequency. The core circuit 10 can be used to achieve frequency conversion between a first frequency and a second frequency based on the received local oscillator signal. The second frequency is different from the first frequency, and the third signal is opposite in phase to the second signal, that is, the phase difference between the third signal and the second signal can be 180 degrees.

[0051] As an optional implementation, the first microstrip line 30 can be used to transmit a first signal to the core circuit 10, the second microstrip line 40 can be used to transmit a second signal output by the core circuit 10, and the third microstrip line 50 can be used to transmit a third signal output by the core circuit 10. That is, the first signal can be an input signal, and the second signal and the third signal can both be output signals. Accordingly, the core circuit 10 can mix the local oscillator signal and the first signal to obtain the second signal and the third signal.

[0052] As another optional implementation, the first microstrip line 30 can be used to transmit the first signal output by the core circuit 10, the second microstrip line 40 can be used to transmit the second signal to the core circuit 10, and the third microstrip line 50 can be used to transmit the third signal to the core circuit 10. That is, the second signal and the third signal can both be input signals, and the first signal can be an output signal. Accordingly, the core circuit 10 can mix the local oscillator signal, the second signal, and the third signal to obtain the first signal.

[0053] It is understandable that the first frequency may be greater than the second frequency. For example, the first signal may be a radio frequency signal, and the second signal and the third signal may both be intermediate frequency signals. Alternatively, the first frequency may be less than the second frequency. For example, the first signal may be an intermediate frequency signal, and the second signal and the third signal may both be radio frequency signals.

[0054] In an embodiment of the present application, if the RF signal is an input signal and the IF signal is an output signal, the mixer can down-convert the RF signal based on the local oscillator signal to obtain the IF signal. Accordingly, the mixer can be a down-converter. Alternatively, if the IF signal is an input signal and the RF signal is an output signal, the mixer can up-convert the IF signal based on the local oscillator signal to obtain the RF signal. Accordingly, the mixer can be an up-converter.

[0055] It can also be understood that the intermediate frequency signal in the embodiment of the present application can also include a zero intermediate frequency signal, that is, a baseband signal. That is, the mixer can realize the frequency conversion between the radio frequency signal and the baseband signal, that is, the mixer can also be applied to the zero intermediate frequency architecture. If the mixer is used to realize the frequency conversion between the radio frequency signal and the intermediate frequency signal, or between the intermediate frequency signal and the baseband signal, the mixer can be applied to the superheterodyne architecture.

[0056] Figure 3 Schematic diagram of the transmission mode of each signal in a mixer provided in an embodiment of the present application. Figure 3 As shown, in the area where the core circuit 10 is located (i.e., the core area of ​​the mixer), the local oscillator signal is transmitted using the slot line main mode, and the first signal, the second signal, and the third signal (i.e., the radio frequency signal and the intermediate frequency signal) are transmitted using the microstrip line main mode. In the area where the core circuit 10 is located, the electric field distribution of the local oscillator signal can be as follows: Figure 4 As shown by the dotted arrow in .

[0057] Combination Figure 3 and Figure 4It can be seen that the electromagnetic field transmission mode of the local oscillator signal is orthogonal to the transmission mode of the RF signal and the transmission mode of the intermediate frequency signal, so it can be ensured that the local oscillator signal will not couple with the RF signal or the intermediate frequency signal. In other words, the energy isolation of the local oscillator signal and other signals can be achieved, thereby effectively reducing the local oscillator leakage of the mixer core.

[0058] Table 1 shows the test results obtained by simulating the image suppression mixer and the local oscillator suppression mixer in the related art, and the mixer provided in the embodiment of the present application. As shown in Table 1, in the 80 GHz frequency band, the image suppression mixer and the local oscillator suppression mixer in the related art cannot achieve the isolation of the local oscillator signal in the core area of ​​the mixer, that is, the local oscillator isolation of both is 0 decibel (dB). However, the mixer provided in the embodiment of the present application can improve the isolation by more than 10 dB. Based on the simulation results, it can be seen that the mixer provided in the embodiment of the present application has a good local oscillator suppression effect in the core area, which can effectively reduce the leakage of the local oscillator signal.

[0059] Table 1

[0060]

[0061] In summary, an embodiment of the present application provides a mixer that can transmit a local oscillator signal through a slot line, and transmit a first signal, a second signal, and a third signal through a microstrip line. Thus, it can be ensured that the transmission mode of the local oscillator signal is different from the transmission mode of the first signal, and different from the transmission modes of the second signal and the third signal, that is, it is possible to achieve transmission mode isolation (mode isolation) of the local oscillator signal from the first signal, and transmission mode isolation from the second signal and the third signal. Since the local oscillator signal is isolated from the electromagnetic field signal transmission mode of other signals, the leakage of the local oscillator signal at other signal ports can be effectively reduced, thereby effectively improving the performance of the mixer.

[0062] Figure 4 Schematic diagram of a core circuit provided by an embodiment of the present application. Figure 4 As shown, the core circuit 10 may include: a first transistor 101 and a second transistor 102. The first electrode of the first transistor 101 is connected to the first electrode of the second transistor 102, and the common terminal formed by the first electrodes of the two transistors may be as shown in FIG. Figure 4 As shown in G0.

[0063] Figure 5 Schematic diagram of a partial structure of a core circuit provided in an embodiment of the present application. Figure 4 and Figure 5It can be seen that one side 201 of the slot line 20 can be connected to the gate G1 of the first transistor 101, and the other side 202 of the slot line 20 can be connected to the gate G2 of the second transistor 102. In addition, the first microstrip line 30 can be connected to the first electrode of the first transistor 101, that is, the first microstrip line 30 can be connected to the common end G0 of the two transistors. The second microstrip line 40 can be connected to the second electrode G3 of the first transistor 101, and the third microstrip line 50 can be connected to the second electrode G4 of the second transistor 102.

[0064] It can be understood that the slot line 20 is composed of two spaced metal plates (or metal wires), one side 201 of the slot line 20 refers to one of the metal plates (or metal wires), and the other side 202 of the slot line 20 refers to the other metal plate (or metal wire). It can also be understood that the first electrode of the transistor can be one of the source and the drain, and the second electrode can be the other of the source and the drain, which is not limited in the embodiment of the present application.

[0065] Optionally, in the embodiment of the present application, the first transistor 101 and the second transistor 102 may both be field effect transistors (FETs). Using FETs as nonlinear units of the mixer can ensure that the linearity of the mixer is high.

[0066] The first transistor 101 and the second transistor 102 may also be FETs with high electron mobility and low knee voltage, so as to further ensure that the frequency conversion efficiency and linearity of the mixer are both high.

[0067] like Figure 4 As shown, the first transistor 101 and the second transistor 102 can be formed on a substrate, and the substrate can be a gallium arsenide (GaAs) substrate. In addition, the transistor can also include an epitaxial layer, a barrier layer, and an electrode layer formed sequentially on the substrate. Among them, the epitaxial layer can be GaAs epitaxial to ensure good material consistency. The material of the barrier layer can be aluminum gallium arsenide (ALGaAs). The material of the electrode layer can be a metal material, and the electrode layer can include the gate, the first pole, and the second pole of the transistor. In addition, a heavily doped GaAs layer can be formed between the electrode layer and the barrier layer.

[0068] Continue to refer Figure 4 , a two-dimensional electron gas (2DEG) is also formed in the epitaxial layer, and a depletion region of the transistor, i.e., a channel region, is formed in the epitaxial layer. The local oscillator signal is loaded on the two sets of gates through the planar slot line 20, thereby controlling the channel state of the two transistors. Or it can be understood that the voltage of the slot line 20 can control the channel state of the transistor.

[0069] In the embodiment of the present application, when the mixer works as an up-converter, the intermediate frequency signal and the local oscillator signal are input signals, and the radio frequency signal is an output signal. At this time, the intermediate frequency signal can drive the first transistor 101 and the second transistor 102 to generate a channel current. When the mixer works as a down-converter, the radio frequency signal and the local oscillator signal are input signals, and the intermediate frequency signal is an output signal. At this time, the radio frequency signal can drive the first transistor 101 and the second transistor 102 to generate a channel current.

[0070] Understandably, reference Figure 3 , the first microstrip line 30 can be used to transmit the radio frequency signal RF, the second microstrip line 40 can be used to transmit the intermediate frequency signal IF-, and the third microstrip line 50 can be used to transmit the intermediate frequency signal IF+. That is, the middle common end of the two transistors can be used as the output or input end of the radio frequency signal RF, and the left and right electrodes of the two transistors can be used as the input or output end of the intermediate frequency signal IF.

[0071] Alternatively, refer to Figure 6 , the first microstrip line 30 can be used to transmit the intermediate frequency signal IF, the second microstrip line 40 can be used to transmit the radio frequency signal RF-, and the third microstrip line 50 can be used to transmit the radio frequency signal RF+. That is, the middle common end of the two transistors can be used as the output or input end of the intermediate frequency signal IF, and the left and right electrodes of the two transistors can be used as the input or output end of the radio frequency signal RF.

[0072] Alternatively, if Figure 5 As shown, the groove line 20, the gate G1 of the first transistor 101, and the gate G2 of the second transistor 102 can be located in the same layer and can be made of the same metal material. Thus, the manufacturing process of the mixer can be effectively simplified and the manufacturing efficiency of the mixer can be improved.

[0073] It is understandable that the microstrip line may include a strip conductor located on top of a dielectric substrate, and a ground plane located below the dielectric substrate. In the embodiment of the present application, the strip conductor of the first microstrip line 30, the strip conductor of the second microstrip line 40, the strip conductor of the second microstrip line 40, the first electrode and the second electrode of the first transistor 101, and the first electrode and the second electrode of the second transistor 102 may also be located in the same layer and may be made of the same metal material.

[0074] Example, reference Figure 4 and Figure 5 The slot line 20, the strip conductors of each microstrip line, and each electrode of the transistor in the core circuit 10 can be located in the same layer and can be made of the same metal material. Thus, the preparation process of the mixer can be effectively simplified and the preparation efficiency of the mixer can be improved.

[0075] As a first optional implementation, Figure 3 As shown, the mixer may further include: a fourth microstrip line 60. The fourth microstrip line 60 may be connected to the slot line 20 and used to transmit a local oscillator signal to the slot line 20. That is, one end of the slot line 20 is connected to the fourth microstrip line 60, and the other end is connected to the core circuit 10. The local oscillator signal transmitted by the fourth microstrip line 60 may be a single-ended signal, which may be converted into a differential signal after being fed into the slot line 20. The slot line 20 may then feed the differential local oscillator signal into the core circuit 10.

[0076] Based on the above analysis and Figure 3 It can be seen that the transmission mode of the local oscillator signal can be converted from the microstrip line main transmission mode to the slot line main transmission mode, thereby realizing the change of the electromagnetic field transmission mode.

[0077] As a second optional implementation, refer to Figure 5 The slot line 20 can be directly connected to a local oscillator port (not shown in the figure) and used to receive a local oscillator signal output by the local oscillator port, and the local oscillator signal output by the local oscillator port is a differential signal. Figure 5 As shown, the differential signal includes a signal LO+ and a signal LO-, and the phases of the signal LO+ and the signal LO- are opposite.

[0078] By directly feeding in a differential local oscillator signal, there is no need to transmit the local oscillator signal from the microstrip line to the slot line and convert the signal transmission mode, which can effectively simplify the structure of the mixer.

[0079] Based on the above two implementations, it can be known that in the embodiment of the present application, the two sides of the slot line 20 are connected to the gates of the two transistors, which can realize the differential feeding of the local oscillator signal, that is, the local oscillator signal fed into the core circuit 10 is a differential signal. Thus, common mode suppression can be provided. Moreover, even if the local oscillator signal leaks to other signal ports of the mixer (such as the RF signal port), it can be ensured that the phase of the leaked local oscillator signal is opposite and the energy is offset, thereby effectively improving the local oscillator suppression.

[0080] like Figure 6 As shown, the mixer may further include: at least one of a first frequency selection circuit 70, a second frequency selection circuit 80, a third frequency selection circuit 90 and a fourth frequency selection circuit 100. For example, Figure 6 The mixer shown includes a first frequency selection circuit 70 , a second frequency selection circuit 80 , a third frequency selection circuit 90 and a fourth frequency selection circuit 100 .

[0081] The first frequency selection circuit 70 is connected to the end of the slot line 20 away from the core circuit 10. If the mixer further includes a fourth microstrip line 60, the first frequency selection circuit 70 can be connected to the slot line 20 through the fourth microstrip line 60. The second frequency selection circuit 80 is connected to the end of the first microstrip line 30 away from the core circuit 10, the third frequency selection circuit 90 is connected to the end of the second microstrip line 40 away from the core circuit 10, and the fourth frequency selection circuit 100 is connected to the end of the third microstrip line 50 away from the core circuit 10.

[0082] It is understood that the frequency selection circuit may also be referred to as a frequency selection network, a frequency selection circuit or a matching network, which is used to achieve signal matching. Figure 6 Each of the first frequency selection circuit 70, the second frequency selection circuit 80, the third frequency selection circuit 90 and the fourth frequency selection circuit 100 may include at least one filter. Of course, the frequency selection circuit may also include other signal processing devices, which is not limited in the embodiment of the present application.

[0083] It can also be understood that the first frequency selection circuit 70 connected to the slot line 20 can achieve matching of the local oscillator signal, and open circuits of the first signal, the second signal, and the third signal. The second frequency selection circuit 80 connected to the first microstrip line 30 can achieve matching of the first signal, open circuits of the local oscillator signal, and short circuits of the second signal and the third signal. The third frequency selection circuit 90 connected to the second microstrip line 40 and the fourth frequency selection circuit 100 connected to the third microstrip line 50 can achieve matching of the second signal and the third signal, open circuits of the local oscillator signal, and short circuits of the first signal.

[0084] In the embodiment of the present application, since the local oscillator signal is isolated from the transmission mode of the first signal, and is isolated from the transmission mode of the second signal and the third signal, the complexity of matching each signal port of the mixer can be effectively reduced, so that each signal port does not need to use a frequency selection circuit with a high suppression ratio. As a result, the structural complexity and area of ​​each frequency selection circuit can be effectively reduced, thereby saving the chip area and cost of the mixer. For example, compared with using a microstrip line to transmit the local oscillator signal, the first signal, the second signal and the third signal, the area and cost of the mixer provided in the embodiment of the present application can be saved by about 30%.

[0085] In summary, an embodiment of the present application provides a mixer that can transmit a local oscillator signal through a slot line, and transmit a first signal, a second signal, and a third signal through a microstrip line. Thus, it can be ensured that the transmission mode of the local oscillator signal is different from the transmission mode of the first signal, and different from the transmission modes of the second signal and the third signal, that is, the transmission mode isolation of the local oscillator signal from the first signal, and the transmission mode isolation from the second signal and the third signal can be achieved. Since the local oscillator signal is isolated from the electromagnetic field signal transmission mode of other signals, the leakage of the local oscillator signal at other signal ports can be effectively reduced, thereby effectively improving the performance of the mixer.

[0086] In addition, the mixer can also use FET as a nonlinear unit, thereby effectively improving the frequency conversion efficiency and linearity of the mixer. Moreover, since the mode isolation of the local oscillator signal and other signals is achieved, the structural complexity of the frequency selection circuit in the mixer can be effectively reduced, thereby reducing the area and cost of the mixer.

[0087] It is understandable that, since the mixer provided in the embodiment of the present application can effectively suppress the local oscillator leakage in the core area (theoretically, it can achieve 100% bandwidth local oscillator suppression at the RF and IF ports), it can be applied to the design and development of multi-band broadband devices. For example, it can be applied to the design of microwave ultra-high frequency broadband circuits to ensure high microwave ultra-high frequency radiation reception efficiency and good mode isolation effect.

[0088] In the embodiments of the present application, the terms "first", "second" and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "at least one" means one or more, and "plurality" means two or more.

[0089] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0090] The above is only an optional implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A mixer, characterized in that: The mixer comprises: a core circuit, a slot line, a first microstrip line, a second microstrip line and a third microstrip line; Wherein, the slot line, the first microstrip line, the second microstrip line and the third microstrip line are all connected to the core circuit; The slot line is used to transmit a local oscillator signal to the core circuit, the first microstrip line is used to transmit a first signal of a first frequency, the second microstrip line is used to transmit a second signal of a second frequency, and the third microstrip line is used to transmit a third signal of the second frequency, the second frequency is different from the first frequency, and the third signal is opposite in phase to the second signal; The core circuit is used to achieve frequency conversion between the first frequency and the second frequency based on the local oscillator signal.

2. The mixer according to claim 1, characterized in that The core circuit comprises: a first transistor and a second transistor, wherein a first electrode of the first transistor is connected to a first electrode of the second transistor; One side of the groove line is connected to the gate of the first transistor, and the other side of the groove line is connected to the gate of the second transistor; The first microstrip line is connected to a first electrode of the first transistor, the second microstrip line is connected to a second electrode of the first transistor, and the third microstrip line is connected to a second electrode of the second transistor.

3. The mixer according to claim 2, characterized in that The first transistor and the second transistor are both field effect transistors.

4. The mixer according to claim 2 or 3, characterized in that: The groove line, the gate of the first transistor, and the gate of the second transistor are located in the same layer.

5. The mixer according to any one of claims 2 to 4, characterized in that: The strip conductor of the first microstrip line, the strip conductor of the second microstrip line, the strip conductor of the third microstrip line, the first electrode and the second electrode of the first transistor, and the first electrode and the second electrode of the second transistor are all located in the same layer.

6. The mixer according to any one of claims 1 to 5, characterized in that: The mixer further includes: a fourth microstrip line; The fourth microstrip line is connected to the slot line and is used to transmit a local oscillator signal to the slot line.

7. The mixer according to any one of claims 1 to 5, characterized in that: The slot line is connected to the local oscillator port and is used to receive a local oscillator signal output by the local oscillator port. The local oscillator signal output by the local oscillator port is a differential signal.

8. The mixer according to any one of claims 1 to 7, characterized in that: The first signal is a radio frequency signal, and the second signal and the third signal are both intermediate frequency signals; Alternatively, the first signal is an intermediate frequency signal, and the second signal and the third signal are both radio frequency signals.

9. The mixer according to any one of claims 1 to 8, characterized in that: The first microstrip line is used to transmit the first signal to the core circuit, the second microstrip line is used to transmit the second signal output by the core circuit, and the third microstrip line is used to transmit the third signal output by the core circuit; Alternatively, the first microstrip line is used to transmit the first signal output by the core circuit, the second microstrip line is used to transmit the second signal to the core circuit, and the third microstrip line is used to transmit the third signal to the core circuit.

10. The mixer according to any one of claims 1 to 9, characterized in that: The mixer further includes: at least one of a first frequency selection circuit, a second frequency selection circuit, a third frequency selection circuit, and a fourth frequency selection circuit; The first frequency selection circuit is connected to the slot line, the second frequency selection circuit is connected to the first microstrip line, the third frequency selection circuit is connected to the second microstrip line, and the fourth frequency selection circuit is connected to the third microstrip line.

11. A signal transmission device, characterized in that: The signal transmission device comprises: an antenna, and a mixer as claimed in any one of claims 1 to 10; The mixer is used to perform frequency conversion on the signal received by the antenna, and / or the mixer is used to transmit the frequency-converted signal to the antenna.

Images