Matching network, mixer, phase shifter, radar sensor, and electronic device

Abstract

The invention discloses a radio frequency signal matching network, a frequency mixer, a phase shifter, a radar sensor and electronic equipment, the radio frequency signal matching network comprises a first inductor with an I-path input end, a second inductor with a Q-path input end, and a third inductor which is inductively coupled with the first inductor and the second inductor, and the third inductor is provided with an output end; wherein the I-path input end is set to receive I-path radio frequency signals, and the Q-path input end is set to receive Q-path radio frequency signals.

Description

Technical Field

[0001] This article relates to but is not limited to the field of semiconductor technology, and in particular to a matching network, mixer, phase shifter, radar sensor and electronic equipment for radio frequency signals. Background Art

[0002] An integrated circuit (IC), also known as a chip, is a way of miniaturizing circuits in electronics and is often manufactured on the surface of a semiconductor wafer. A chip consists of a die manufactured using semiconductor manufacturing processes and a packaging structure.

[0003] The structure of the RF chip usually includes a mixer for frequency conversion. Among them, some mixers, such as single-sideband mixers, are widely used due to their good suppression of image signals. However, the output circuit of the single-sideband mixer needs to mix the I (in-phase) and Q (quadrature) signals with a phase difference of 90° for subsequent circuit processing. However, when mixing, the two signals are prone to poor isolation. These problems may also exist in other circuits that need to achieve IQ signal mixing, such as IQ phase shifters. Summary of the invention

[0004] The embodiments of the present disclosure provide a matching network, a mixer, a phase shifter, a radar sensor and an electronic device for a radio frequency signal, which can avoid leakage between IQ paths and improve isolation.

[0005] On the one hand, an embodiment of the present disclosure provides a matching network for a radio frequency signal, comprising a first inductor having an I-path input terminal, a second inductor having a Q-path input terminal, and a third inductor inductively coupled to both the first inductor and the second inductor, the third inductor having an output terminal; wherein the I-path input terminal is configured to receive an I-path radio frequency signal, and the Q-path input terminal is configured to receive a Q-path radio frequency signal.

[0006] On the other hand, an embodiment of the present disclosure further provides a mixer including the aforementioned matching network.

[0007] On the other hand, an embodiment of the present disclosure further provides a phase shifter including the aforementioned matching network.

[0008] On the other hand, an embodiment of the present disclosure further provides a radar sensor, comprising the aforementioned mixer or phase shifter.

[0009] On the other hand, an embodiment of the present disclosure also provides an electronic device including the aforementioned radar sensor.

[0010] By respectively setting a first inductor for the I input, a second inductor for the Q input, and a third inductor for the output, the three inductors are inductively coupled and connected, thereby avoiding the problem of poor isolation caused by short-circuiting the I and Q paths.

[0011] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present disclosure. Other advantages of the present disclosure can be realized and obtained by the schemes described in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings are used to provide an understanding of the technical solution of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solution of the present disclosure and do not constitute a limitation on the technical solution of the present disclosure. The shapes and sizes of the components in the accompanying drawings do not reflect the actual proportions and are only intended to illustrate the contents of the present disclosure.

[0013] Figure 1 It is a schematic diagram of signal leakage of single sideband mixer;

[0014] Figure 2 A schematic diagram of the connection relationship between an IQ mixer and an IQ synthesis matching network;

[0015] Figure 3 A circuit diagram of a matching network for radio frequency signals provided in an embodiment of the present disclosure;

[0016] Figure 4A A schematic diagram of the shape and position relationship of the first inductor and the second inductor according to an embodiment of the present disclosure;

[0017] Figure 4B is a schematic diagram of a shape of a third inductor according to an embodiment of the present disclosure;

[0018] Figure 4C A schematic diagram of a matching network according to an embodiment of the present disclosure;

[0019] Figure 5A A schematic diagram of another shape and position relationship of the first inductor and the second inductor according to an embodiment of the present disclosure;

[0020] Figure 5B is a schematic diagram of another shape of the third inductor according to the embodiment of the present disclosure;

[0021] Figure 5C Another schematic diagram of a matching network according to an embodiment of the present disclosure;

[0022] Figure 6 A schematic diagram of the position of the third inductor according to an embodiment of the present disclosure;

[0023] Figure 7is another schematic diagram of the position of the third inductor according to the embodiment of the present disclosure;

[0024] Figure 8 This is a schematic diagram of passive matching network signal synthesis according to an embodiment of the present disclosure;

[0025] Fig. 9 A schematic diagram of a connection method of a tap according to an embodiment of the present disclosure;

[0026] Fig.10 A schematic diagram of another connection method of the taps in the embodiment of the present disclosure;

[0027] Fig.11 A schematic diagram of another connection method of the tap in the embodiment of the present disclosure;

[0028] Fig. 12A is a connection diagram of the first tap and the first inductor;

[0029] Fig. 12B is a schematic diagram of connection between the second tap and the second inductor;

[0030] Fig.13 This is a circuit diagram of a radar chip;

[0031] Fig.14 It is a schematic diagram of applying a passive matching network to an IQ phase shifter according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0032] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0033] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0034] In this specification, "parallel" means that two straight lines on a plane, or two straight lines in space, or two planes in space, or a straight line in space and a plane do not have any common points, and "perpendicular" means that a line on a plane intersects with another line and forms a right angle, or a line in space intersects with another straight line and forms a right angle, or two planes in space intersect and form a right angle, or a straight line in space and a plane intersect and form a right angle. However, considering the actual implementation of the process, there may be a certain error, so the "parallel" mentioned herein includes approximately parallel, and the "perpendicular" mentioned herein includes approximately perpendicular.

[0035] In the present specification, "plurality" and "two or more" have the same meaning, and "two or more" includes "two".

[0036] In RF bands such as the millimeter wave band, due to the compact layout area, the circuits that generate I and Q signals are inevitably physically short in the area where the signals are synthesized and output. This makes it easy for the two signals to leak between the I and Q channels and between the IQ circuit and the output circuit through magnetic coupling, substrate coupling, electrical coupling, etc., reducing the isolation between the I and Q signal lines. In circuits such as IQ mixers, the image suppression ratio may also be reduced, and the local oscillator leakage may worsen.

[0037] Figure 1 Figure 1 is a schematic diagram of signal leakage of a single sideband mixer. Figure 1As shown, the I input signal passes through the I matching network (I Matching Networks) and the I mixer (I Mixer) to reach the IQ combined matching network (IQ Combine & Matching Networks), and the Q input signal passes through the Q matching network (Q Matching Networks) and the Q mixer (Q Mixer) to reach the IQ combined matching network. The I signal and the Q signal are output through the IQ combined matching network. A matching network is a circuit used to adjust the impedance matching between the input and output of a circuit. By selecting appropriate component parameters and topology, the matching network can achieve maximum power transmission and optimization of signal quality. It can be seen from the figure that there is leakage between the two IQ matching networks and between the two IQ matching networks and the mixer output.

[0038] In order to ensure the synthesis and impedance matching of the IQ two-way signal, the connection relationship between the IQ mixer and the IQ synthesis matching network is as follows: Figure 2 As shown, the outputs of the two IQ mixers are short-circuited together, and then matched to the subsequent circuit through an IQ synthesis matching network. The IQ synthesis matching network, for example, includes a multi-stage circuit of a matching circuit and a transformer. However, this circuit may cause leakage problems due to the short-circuit of the two IQ circuits or the multi-stage circuit, and the part where the I mixer is connected to the IQ synthesis matching network and the part where the Q mixer is connected to the IQ synthesis matching network have incomplete symmetry in the routing, which leads to the problem of asymmetry of the differential mode and common mode paths of the two IQ channels.

[0039] To this end, an embodiment of the present disclosure provides a matching network for a radio frequency signal, which is used for IQ synthesis and impedance matching, wherein the matching network includes a first inductor having an I-path input end, a second inductor having a Q-path input end, and a third inductor inductively coupled to both the first inductor and the second inductor, wherein the third inductor has an output end (i.e., the output end of the matching network, which is used to connect to a lower-level circuit); wherein the I-path input end is configured to receive an I-path radio frequency signal, and the Q-path input end is configured to receive a Q-path radio frequency signal. Figure 3 This is a circuit diagram of a matching network for radio frequency signals provided in an embodiment of the present disclosure, wherein the inductor in the diagram is merely a schematic diagram of the circuit connection.

[0040] In the embodiment of the present disclosure, a first inductor is provided for the I input, a second inductor is provided for the Q input, and a third inductor is provided for the output, and three inductors are inductively coupled and connected. By using multiple inductive couplings, the wiring spacing between the IQ signals is increased, that is, the isolation of the IQ signals is increased, and the synthesis of the IQ signals is realized.

[0041] The above-mentioned inductive coupling refers to the coupling connection between circuits or devices through the interaction of magnetic fields. It uses the principle of electromagnetic induction to transfer signals from one coil to another, realizing contactless transmission of signals.

[0042] In an exemplary embodiment, the first inductor and the second inductor are symmetrically arranged. Specifically, the first inductor and the second inductor are symmetrical about a symmetry axis. Thus, the I input terminal and the Q input terminal are also symmetrical about the symmetry axis. By symmetrical arrangement, the introduction of additional phase error due to the inconsistent routing lengths from the I input terminal and the Q input terminal to the transformer coil is avoided. By completely symmetrical arrangement, the robustness of the passive network and the resistance to process instability are improved.

[0043] For example, the I-way input terminal and the Q-way input terminal are arranged along the second direction (longitudinal Y-axis direction), and the center line between the two extends along the first direction (lateral X-axis direction), and the center line is also the symmetry axis of the I-way input terminal and the Q-way input terminal). The first direction is perpendicular to the second direction. The first inductor and the second inductor can be arranged between the I-way input terminal and the Q-way input terminal, and are symmetrical along the first direction, and the symmetry axis along the first direction is the first symmetry axis. That is, the I-way input terminal and the Q-way input terminal are symmetrically arranged at a position away from the first symmetry axis, and the coil bodies of the first inductor and the second inductor are symmetrical along the first symmetry axis. By setting the passive network between the IQ input terminals, the physical distance between the IQ input terminals is increased, the mutual coupling between the IQ signals can be reduced, the image suppression ratio can be improved, it is more conducive to suppressing the signal leakage between the IQ channels, and it is convenient for layout. By symmetrically arranging the I input terminal and the Q input terminal at positions far away from the first symmetry axis, in addition to suppressing signal leakage between the I and Q paths, phase errors can be avoided, and the robustness of the passive network and resistance to process instability can be improved.

[0044] In an exemplary embodiment, the first inductor and the second inductor may both be symmetrical structures. The symmetry axis of the first inductor and the symmetry axis of the second inductor may be the same symmetry axis, or different symmetry axes. For example, the first inductor and the second inductor are each symmetrical along the second direction, and the symmetry axis along the second direction is the second symmetry axis. For example, the second symmetry axis is perpendicular to the first symmetry axis. By setting the first inductor and the second inductor to be symmetrical structures, the passive network is made more symmetrical, and the robustness of the passive network is further improved. For example, the shapes of the first inductor and the second inductor may be the same.

[0045] Figure 4A is an example of the positional relationship between the first inductor and the second inductor. Figure 4AIn the embodiment, the first inductor and the second inductor are basically located in the first metal layer. In order to prevent connection, the coil connection is achieved through metal vias and the second metal layer. The first inductor L1 and the second inductor L2 are arranged along the second direction Y, and the symmetry axis of the first inductor L1 and the second inductor L2 is the first symmetry axis C1. In this example, L1 and L2 are each symmetrical along the second symmetry axis C2.

[0046] In an exemplary embodiment, the orthographic projection of the first inductor and the orthographic projection of the second inductor may be arranged to partially overlap, that is, the two are arranged to overlap, and the intersection position may be insulated by routing another metal layer. In this way, the first inductor, the second inductor and the third inductor can be better coupled.

[0047] In order to make the third inductor better coupled with the first inductor and the second inductor, the third inductor may also be a symmetrical structure. In some embodiments, the third inductor may not be a symmetrical structure. Optionally, the symmetry axis of the third inductor may be parallel to or overlap with the first symmetry axis of the first inductor and the second inductor.

[0048] In an exemplary embodiment, the I input terminal and the Q input terminal are arranged orthogonally to the output terminal, respectively. Figure 4C As shown, the first inductor and the second inductor are arranged along the second direction Y, that is, the I-path input end and the Q-path input end are arranged along the second direction Y, the symmetry axis of the third inductor extends along the first direction X, and the output end is located at the symmetry axis of the third inductor. Since the first direction X is perpendicular to the second direction Y, the output end is arranged orthogonally to the I-path input end, and the output end is arranged orthogonally to the Q-path input end.

[0049] In an exemplary embodiment, the envelope shape of the orthographic projection of the first inductor and the second inductor as a whole may be, for example, a regular octagon. Figure 4A As shown, the first inductor and the second inductor as a whole include an L1 main body part and an L2 main body part. As shown in the figure, the main body parts of the first inductor and the second inductor are approximately a regular octagon as a whole. Taking the first inductor as an example, the main body part of the first inductor is the coil body, and the connecting part is the part connecting the coil body to the I-way input terminal. Similarly, the main body part of the second inductor is the coil body, and the connecting part is the part connecting the coil body to the Q-way input terminal. The envelope shape of the orthographic projection of the first inductor and the second inductor as a whole is approximately a regular octagon. Alternatively, the envelope shape of the orthographic projection of the first inductor and the second inductor as a whole can also be a rectangle (including a square), such as Figure 5A Alternatively, the envelope shape of the first inductor and the second inductor as a whole may also be other regular polygons or circles to ensure that the first inductor and the second inductor are symmetrical along the first symmetry axis.

[0050] In an exemplary embodiment, the metal lines constituting the first inductor and the second inductor may be straight lines or curved lines, as long as the first inductor and the second inductor are symmetrical along the first symmetry axis.

[0051] The electromagnetic coupling between the third inductor and the first inductor and the second inductor respectively suppresses one group of image signals flowing through the third inductor and enhances another group of image signals, thereby effectively improving the image suppression ratio.

[0052] In an exemplary embodiment, in order to better couple with the first inductor and the second inductor, the orthographic projection shape of the third inductor can be adapted to the orthographic projection envelope shape of the first inductor and the second inductor. For example, the orthographic projection envelope shape of the first inductor and the second inductor is a regular octagon, and the main body of the third inductor can also be set to a regular octagon, such as Figure 4B For example, the envelope shape of the orthographic projection of the first inductor and the second inductor is a square, and the main body of the third inductor can also be set to a square, such as Figure 5B In other examples, the orthographic projection shape of the third inductor may not match the orthographic projection shapes of the first inductor and the second inductor.

[0053] In an exemplary embodiment, the third inductor may be located between the first inductor and the second inductor. Specifically, the orthographic projection of the third inductor is located between the orthographic projection of the first inductor and the orthographic projection of the second inductor. Figure 4C Shown and Figure 5C As shown, or it can be located inside the positive projection area (or inside the envelope shape) of the first inductor and the second inductor, as shown Figure 6 As shown, or it can be located outside the positive projection area (or outside the envelope shape) of the first inductor and the second inductor, as shown Figure 7 The size of the third inductor can be determined by the resonant inductor required by the next stage circuit, and its shape and length are not limited by the shapes of the first inductor and the second inductor.

[0054] By setting the third inductor symmetrically along the third symmetry axis, the orthographic projection of the third symmetry axis coincides with the orthographic projection of the first symmetry axis. After the third inductor is coupled with the first inductor and the second inductor, part of the signals inputted into the I-path and Q-path can be offset, and another part of the signals inputted into the I-path and Q-path can be enhanced, thereby outputting a single-sideband signal.

[0055] by Figure 4C The matching network shown is applied to a mixer, and the input signals are the local oscillator signal (LO) and the baseband signal (BB). Figure 8 This is a schematic diagram of signal synthesis, showing the current direction and magnetic field direction in the matching network.

[0056] The voltage of LO entering the IQ two-way P and N is shown in equation (1).

[0057] V LOIP =A LO cos(ω LO t); V LOIN =-A LO cos(ω LO t)

[0058] V LOQP =A LO sin(ω LO t); V LOQN =-A LO sin(ω LO t) (1)

[0059] The voltage of BB entering the two paths P and N of IQ is shown in equation (2):

[0060] V BBIP =A BB cos(ω BB t); V BBIN =-A BB cos(ω BB t)

[0061] V BBQP =A BB sin(ω BB t); V BBQN =-A BB sin(ω BB t) (2)

[0062] Where A represents amplitude, ω represents angular velocity, and t represents time.

[0063] According to equations (1) and (2), the output voltage of the mixer is as shown in equation (3):

[0064] V RFIP =V LOIP *V BBIP +V LOIN *V BBIN

[0065] =A LO A BB [cos(ω LO t+ω BB t)+cos(ω LO t-ω BB t)]

[0066] V RFIN =V LOIP *V BBIN +VLOIN *V BBIP

[0067] =-A LO A BB [cos(ω LO t + ω BB t) + cos(ω LO t - ω BB t)]

[0068] V RFQP =V LOQP *V BBQP +V LOQN *V BBQN

[0069] =A LO A BB [cos(ω LO t + ω BB t) - cos(ω LO t - ω BB t)]

[0070] V RFQN =V LOQP *V BBQN +V LOQN *V BBQP

[0071] =-A LO A BB [cos(ω LO t + ω BB t) - cos(ω LO t - ω BB t)] (3)

[0073] Assume lsb = A LO A BB cos(ω LO t - ω BB t); usb = A LO A BB cos(ω LO t + ω BB t)

[0074] Equation (3) can be expressed as the following:

[0075] V RFIP = lsb + usb

[0076] V RFIN =-lsb - usb

[0077] V RFQP = usb - lsb

[0078] V RFQN =-usb+lsb

[0079] It can be seen from the accompanying drawings that at this time, the LSB magnetic fields are superimposed and the USB magnetic fields are offset, so a single sideband signal can be output, thereby saving spectrum resources and transmission power.

[0080] In an exemplary embodiment, the first inductor may also have a first tap for connecting a bias power supply (VDD), and the first tap may be arranged near an input terminal of the I path, or near an input terminal of the Q path. Taking the application of the matching network to a mixer as an example, the bias power supply is used to provide an appropriate bias voltage for the mixer to keep the mixer working normally.

[0081] In an exemplary embodiment, the second inductor may further have a second tap for connecting a bias power supply, and the second tap may be disposed at a position close to the Q-path input terminal, or at a position close to the I-path input terminal.

[0082] In an exemplary embodiment, the first tap of the first inductor and the second tap of the second inductor are symmetrically arranged. For example, the first tap and the second tap are symmetrical along the first symmetry axis. Taking the application of the matching network to a mixer as an example, the first tap of the first inductor and the I-channel mixer can form an I-mixer common-mode path, and the second tap of the second inductor and the Q-channel mixer can form a Q-mixer common-mode path. When the first tap and the second tap are symmetrically arranged, the mixer output common-mode path can be made more symmetrical. In addition, by setting taps for the first inductor and the second inductor respectively, the voltages of the I-channel mixer and the Q-channel mixer can be adjusted respectively, which is more flexible.

[0083] In an exemplary embodiment, the connection point of the first tap and the first inductor is located at the center line between the P end and the N end of the I-path input end (hereinafter referred to as the I-path P end and the N end), so that the length of the common mode path of the P end and the common mode path of the N end in the I-path are equal; similarly, the connection point of the second tap and the second inductor is located at the center line between the P end and the N end of the Q-path input end (hereinafter referred to as the Q-path P end and the N end), so that the length of the common mode path of the P end and the common mode path of the N end in the Q-path are equal. Since the length of the common mode path of the P end and the N end in the two paths is equal, the symmetry of the PN is better, the leakage of the local oscillator signal will be smaller, and the problem of asymmetry between the common mode path and the differential mode path is solved.

[0084] In an exemplary embodiment, taking the matching network connecting the I-channel mixer and the Q-channel mixer as an example, a tap connection method can be as follows: Fig. 9As shown, it can be seen that the first tap and the second tap are symmetrical along the first symmetry axis, and the connection point of the first tap and the first inductor is on the center line between the P terminal and the N terminal of the I-way. In this example, the first tap is T-shaped. Specifically, the T-shaped first tap includes a first main line and a first connecting line. The first connecting line is used to connect the first main line and the first inductor. The orthographic projection of the first connecting line coincides with the orthographic projection of the PN center line of the I-way input terminal. The connection point of the first connecting line and the first inductor is located on a metal line of the first inductor away from the I-way input terminal, and the first connecting line extends in a direction away from the I-way input terminal, so that the first main line is away from the I-way input terminal and the I-way common-mode path is extended. Similarly, the second tap is T-shaped, including a second main line and a second connecting line, the second connecting line is used to connect the second main line and the second inductor, the orthographic projection of the second connecting line coincides with the orthographic projection of the PN center line of the Q-path mixer, the connection point between the second connecting line and the second inductor is located on a metal line of the second inductor away from the Q-path input end, and the second connecting line extends in a direction away from the Q-path input end, so that the second main line is away from the Q-path input end, thereby extending the Q-path common-mode path.

[0085] Another way to connect the tap is as follows Fig.10 As shown, Fig. 9 The difference between the examples is that the first connecting line extends toward the direction close to the input end of the I channel, and in this example, the I channel common mode path is smaller than Fig. 9 In the example, the I common mode path, similarly, the second connecting line extends toward the direction close to the Q input end. In this example, the Q common mode path is smaller than Fig. 9 Common-mode path of the Q mixer in the example.

[0086] Fig.11 This is another example of a connection method of taps. In this example, the first tap and the second tap are symmetrical along the first symmetry axis C1. Fig. 9 The difference between the examples is that in this example, the first tap includes a first main line and a plurality of first connecting lines. Fig. 12A As shown, the first main line is located between the main part of the first inductor and the I-way input terminal, and the plurality of first connecting lines are in a "Y" shape. The first connecting line has a connection point with the first inductor, and the connection point is located on the center line of the I-way input terminal PN. The first connecting line has two connection points with the first main line, and the Y-shaped first connecting line is symmetrical along the second symmetry axis C2. Fig. 12B The second tap also includes a second main line and a plurality of second connection lines, which are symmetrical with the first tap as a whole, and will not be described in detail here. The common mode path in this example is more certain and is not easily interfered by other circuits.

[0087] The matching network provided in the embodiment of the present disclosure performs power synthesis through magnetic coupling, which has stronger isolation than electrical coupling and is conducive to signal isolation between the I and Q paths. In addition, since the common mode paths of the I path and the Q path are separately set, the error can be adjusted separately, and the configuration is more flexible.

[0088] The matching network provided in the embodiments of the present disclosure can be applied to a mixer (e.g., a single-sideband mixer) or a phase shifter, etc. Taking the up-conversion mixer in the transmission channel and / or the on-chip self-detection module as an example, the matching network is connected to the output ends of the I-channel mixer and the Q-channel mixer to output the mixed single-sideband signal. Specifically, the I-channel mixer is connected to the I-channel input end in the matching network, and the Q-channel mixer is connected to the Q-channel input end in the matching network. Taking the IQ phase shifter as an example, the matching network is connected to the output ends of the I-channel phase shift circuit and the Q-channel phase shift circuit to output the phase-shifted RF signal, specifically, the I-channel phase shifter is connected to the I-channel input end in the matching network, and the Q-channel phase shifter is connected to the Q-channel input end in the matching network.

[0089] A radar chip is a circuit constructed based on the Doppler effect between electromagnetic waves and speed, which is used to convert physical quantities in physical space into electrical signals. Fig.13The circuit principle structure of the radar chip is shown, which includes a transmitter, a receiver, an analog-to-digital converter (ADC) and a digital signal processor. Among them, the transmitter includes a signal generator, a local oscillator circuit, a radio frequency transmission circuit, and a transmitting antenna, etc.; optionally, the radio frequency transmission circuit optionally includes an IQ phase shifter (not shown in the figure). The receiver includes: a receiving antenna (Antenna) and a mixer (Mixer), etc. Among them, the signal generator generates a signal with continuous frequency change, and outputs it to the local oscillator circuit to form an LO signal of the transmission frequency band; the radio frequency transmission circuit can drive and amplify the LO signal, and even adjust the phase control to form a chirp signal and convert it into an electromagnetic wave through the transmitting antenna. The electromagnetic wave is reflected by the object to form an echo, and the receiving antenna converts the echo into an echo signal. The mixer uses the LO signal to down-convert the echo signal into an intermediate frequency signal; the analog-to-digital converter converts the intermediate frequency signal into a digital signal. Among them, the digital signal corresponding to each chirp output by the analog-to-digital converter is also called a digital sequence. Using the above-mentioned transceiver circuit, the radar chip can integrate multiple independent transceiver ports to cooperate with the antenna array to form a MIMO channel, so that not only can the antenna array be used for detection in a larger range, but also the detection accuracy can be improved. The digital signal processor performs data processing on the accumulated digital sequences of each receiving port to locate the relative position of the target and the radar chip. Among them, the digital signal processor is such as a DSP (Digital Signal Processor) or a dedicated hardware accelerator. The digital signal processor performs at least one of the following signal processing: improving SNR, FFT-based signal processing, CFAR, MIMO-based target estimation, etc., to obtain the relative position.

[0090] In the example of the above radar chip, its mixer may be an IQ mixer, and the output circuit of the mixer may include the matching network provided in the above solution.

[0091] The mixer is used to mix two or more signals of different frequencies. Its main function is to achieve frequency conversion. For example, a high-frequency signal is mixed with a signal of a local oscillator to obtain an intermediate frequency signal. In more applications, mixers can also be used in communication systems, radars, radio receivers and other fields.

[0092] Adding a matching network to the mixer can achieve impedance matching in the circuit. The matching network can adjust the value and connection mode of the circuit elements to match the impedance between the input and output to maximize the transmission of signal energy and reduce reflection and power consumption. In this example, the matching network of this embodiment is added to the IQ mixer and the lower circuit, the I mixer is connected to the I input end, and the Q mixer is connected to the Q input end. Figure 4C , Figure 5C , Figure 6 or Figure 7As shown, on the one hand, the physical distance between the IQ paths increases, which can reduce the mutual coupling between the IQ paths and improve the image suppression ratio. On the other hand, since the passive network is more symmetrical, the IQ paths are completely consistent and symmetrical. This layout will be more robust in the subsequent manufacturing process, and will be more resistant to process instability, making it more suitable for millimeter wave circuits that are extremely sensitive to layout. The above matching circuit for the mixer may also have a tap connected to the bias power supply, such as Fig. 9 , Fig.10 or Fig.11 As shown, on the one hand, the I-path common mode and the Q-path common mode can be adjusted separately, and on the other hand, compared with the related art, the mixer output common mode path is more symmetrical. As shown in the figure, in this example structure, the transformer tap is on the center line of PN, so the common mode path lengths of P and N are equal, which makes PN more symmetrical, so that the leakage of the local oscillator signal will be smaller.

[0093] The matching network described in this embodiment can also be applied to the phase shifter of the radar chip. The phase shifter is used to change the phase of the signal. It can control or adjust the phase of the input signal relative to the output signal. When the matching network is applied to the IQ phase shifter, the signal received by the RF transmitting circuit is divided into two paths, IQ, and enters the I-path phase shift circuit and the Q-path phase shift circuit respectively. The I-path phase shift circuit is connected to the I-path input end of the matching network of this embodiment, and the Q-path phase shift circuit is connected to the Q-path input end of the matching network of this embodiment to achieve impedance matching between the input and output. Fig.14 Shown is Figure 4C The matching network shown is a schematic diagram of connecting an IQ phase shifter as an example. The I-way phase shift circuit and the Q-way phase shift circuit are respectively controlled by control signals of their corresponding phase shift steps to change the phases of the I and Q signals, and then synthesize a phase-shifted signal through the matching network and output it to the lower-level circuit, such as PA, so as to push the RF signal to the antenna. Since the matching network of this embodiment is adopted, it still has the aforementioned advantages of suppressing IQ signal leakage, strong layout robustness, and suppressing local oscillator signal leakage, which will not be repeated here.

[0094] Optionally, in an exemplary embodiment of the present disclosure, the frequency modulated continuous wave signal is a millimeter wave signal, so that the electronic device can be applied to fields such as autonomous driving, industrial automation, smart home appliances, and security inspection.

[0095] Optionally, the radar sensor may be an AiP millimeter-wave radar chip integrated with an antenna. In other embodiments of the present application, the radar sensor may also be other types of radar chips, which is not limited herein.

[0096] In an exemplary embodiment, the present disclosure also provides an electronic device including the aforementioned radar sensor.

[0097] Exemplarily, the electronic device includes: a device body; and electronic devices such as the radar sensor of the above-mentioned embodiment arranged on the device body. The device body is a structure that carries a radio device and is connected to the radio device signal. The radio device transmits and / or receives a radio signal that has been phase-shifted by a phase shifter to achieve functions such as target detection and / or communication within the range of beam scanning, so as to provide the device body with detection target information and / or communication information, thereby assisting or even controlling the operation of the device body.

[0098] In an optional embodiment, the electronic device including the device body and the aforementioned at least one radio device may be a component or product used in fields such as smart housing, transportation, smart home, consumer electronics, monitoring, industrial automation, in-cabin detection, and health care. For example, the device body may be intelligent transportation equipment (such as automobiles, bicycles, motorcycles, ships, subways, trains, etc.), security equipment (such as cameras), liquid level / flow rate detection equipment, intelligent wearable devices (such as bracelets, glasses, etc.), smart home equipment (such as sweeping robots, door locks, televisions, air conditioners, smart lights, etc.), various communication devices (such as mobile phones, tablet computers, etc.), and gates, intelligent traffic lights, intelligent signs, traffic cameras, and various industrialized mechanical arms (or robots), etc. It may also be various instruments for detecting life characteristic parameters and various equipment equipped with the instruments, such as in-cabin detection of automobiles, indoor personnel monitoring, intelligent medical equipment, consumer electronic equipment, etc.

Claims

1. A matching network for a radio frequency signal, characterized in that: It includes a first inductor having an I-path input end, a second inductor having a Q-path input end, and a third inductor inductively coupled to both the first inductor and the second inductor, wherein the third inductor has an output end; wherein the I-path input end is configured to receive an I-path radio frequency signal, and the Q-path input end is configured to receive a Q-path radio frequency signal.

2. The matching network according to claim 1, characterized in that: The first inductor and the second inductor are symmetrically arranged.

3. The matching network according to claim 1, characterized in that: The I-path input terminal and the Q-path input terminal are symmetrically arranged at positions far away from the symmetry axis of the first inductor and the second inductor.

4. The matching network according to claim 1, characterized in that: The first inductor and the second inductor are both symmetrical structures.

5. The matching network according to claim 1 or 2, characterized in that: The orthographic projection of the first inductor partially overlaps with the orthographic projection of the second inductor.

6. The matching network according to claim 1, characterized in that: The third inductor has a symmetrical structure.

7. The matching network according to claim 6, characterized in that: The symmetry axis of the third inductor is parallel to or overlaps with the symmetry axes of the first inductor and the second inductor.

8. The matching network according to claim 1, characterized in that: The I input end and the Q input end are respectively arranged orthogonally to the output end.

9. The matching network according to claim 1, characterized in that: The first inductor and the second inductor have the same shape.

10. The matching network according to claim 1 or 9, characterized in that: The envelope shapes of the first inductor and the second inductor are regular polygons, rectangles, or circles.

11. The matching network according to claim 1 or 6, characterized in that: The third inductor is located between the first inductor and the second inductor, or is located inside the envelope shape of the first inductor and the second inductor, or is located outside the envelope shape of the first inductor and the second inductor.

12. The matching network according to claim 1, characterized in that: The first inductor also has a first tap for connecting a bias power supply, and the first tap is close to the Q-path input terminal or close to the I-path input terminal.

13. The matching network according to claim 1, characterized in that: The second inductor also has a second tap for connecting a bias power supply, and the second tap is close to the I input terminal or close to the Q input terminal.

14. The matching network according to claim 1, characterized in that: The first tap of the first inductor and the second tap of the second inductor are symmetrically arranged.

15. A mixer, characterized in that: The invention comprises an I-channel mixer, a Q-channel mixer and a matching network for a radio frequency signal as claimed in any one of claims 1 to 14, wherein the I-channel mixer is connected to an I-channel input terminal of the matching network, and the Q-channel mixer is connected to a Q-channel input terminal of the matching network.

16. A phase shifter, characterized in that: A matching network for a radio frequency signal comprising an I-path phase shifter, a Q-path phase shifter, and any one of claims 1 to 14, wherein the I-path phase shifter is connected to an I-path input end of the matching network, and the Q-path phase shifter is connected to a Q-path input end of the matching network.

17. A radar sensor, characterized in that: comprising the mixer as claimed in claim 15 or comprising the phase shifter as claimed in claim 16.

18. An electronic device, characterized in that: Comprising the radar sensor as claimed in claim 17.

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