CN215219151U

CN215219151U - Doppler microwave detection module

Info

Publication number: CN215219151U
Application number: CN202121385466.XU
Authority: CN
Inventors: 邹高迪; 邹新
Original assignee: Shenzhen Merrytek Technology Co Ltd
Current assignee: Shenzhen Merrytek Technology Co Ltd
Priority date: 2021-06-21
Filing date: 2021-06-21
Publication date: 2021-12-17
Anticipated expiration: 2031-06-21

Abstract

The utility model provides a Doppler microwave detection module, wherein Doppler microwave detection module includes an electric bridge, wherein is maintaining the impedance characteristic's of electric bridge state is through restraining the mode of the signal of telecommunication transient in the electric bridge is guaranteed the impedance matching of Doppler microwave detection module is formed when being designed to be right the promotion of the frequency selection characteristic of Doppler microwave detection module corresponds Doppler microwave detection module only is in the operating frequency range presents lower loss and by the frequency bandwidth of narrowing, and is corresponding Doppler microwave detection module's frequency selection characteristic is excellent and can ensure Doppler intermediate frequency signal's output signal intensity and anti-interference ability, and then is favorable to improving the detection precision of Doppler microwave detection module to the motion of the object in the corresponding detection space.

Description

Doppler microwave detection module

Technical Field

The utility model relates to a doppler microwave surveys the field, especially relates to a doppler microwave surveys module.

Background

With the development of the internet of things technology, the requirements of artificial intelligence, smart home and intelligent security technology on environment detection, particularly on detection accuracy of human existence, movement and micro motion are higher and higher, and accurate judgment basis can be provided for intelligent terminal equipment only by acquiring a stable enough detection result. Among them, the radio technology, including the microwave detection technology based on the doppler effect principle, is used as a person and an object, and the important junction between the objects has unique advantages in the behavior detection and the existence detection technology, and can detect the action characteristics, the movement characteristics and the micromotion characteristics of a moving object, such as a person, even the heartbeat and the respiration characteristic information of the person without invading the privacy of the person, thereby having wide application prospect.

Specifically, the doppler microwave detection module in the prior art transmits a probe beam corresponding to the frequency of a local oscillator signal in a corresponding detection space through a mixer, and receives an echo formed by the probe beam being reflected by at least one object in the detection space to receive a feedback signal, wherein the mixer receives the feedback signal and outputs a doppler intermediate frequency signal corresponding to the frequency difference between the local oscillator signal and the feedback signal in a frequency mixing detection manner, and then the fluctuation of the doppler intermediate frequency signal in amplitude theoretically corresponds to the motion of the object in the detection space based on the doppler effect principle. Wherein, in order to ensure the feedback precision of the doppler intermediate frequency signal to the motion of the object in the detection space, based on the advantages of small noise and high sensitivity of the existing balanced mixer, the mixer of the doppler microwave detection module in the prior art mainly adopts a balanced mixer. Referring specifically to fig. 1 and 2 of the drawings accompanying the present specification, the equivalent circuit principle of the prior art balanced mixer and a microstrip balanced mixer using a two-branch 3dB bridge based on the equivalent circuit principle are respectively illustrated, wherein the balanced mixer includes a ring bridge 10P, two mixing pipes 20P and an intermediate frequency output port 30P, wherein the ring bridge 10P has a local oscillator signal input port 101P, a feedback signal input port 102P, a first mixing port 103P, a second mixing port 104P, a first microstrip arm 11P connected between the local oscillator signal input port 101P and the feedback signal input port 102P, a second microstrip arm 12P connected between the feedback signal input port 102P and the first mixing port 103P, a third microstrip arm 13P connected between the first mixing port 103P and the second mixing port 104P, and a fourth microstrip arm 14P connected between the second mixing port 104P and the local oscillation signal input port 101P, wherein the local oscillation signal input port 101P, the feedback signal input port 102P, the first mixing port 103P and the second mixing port 104P are sequentially arranged in a circular direction to form a microstrip frame structure in which the first microstrip arm 11P, the second microstrip arm 12P, the third microstrip arm 13P and the fourth microstrip arm 14P are connected end to end, wherein two ends of the two mixing pipes 20P having different polarities and belonging to different mixing pipes 20P are respectively connected to the first mixing port 103P and the second mixing port 104P, and the other two ends of the two mixing pipes 20P having different polarities and belonging to different mixing pipes 20P are connected to the same ground to ensure that the two ends are short-circuited to-ground at a high frequency, correspondingly, the two grounded ends of the two mixing tubes 20P are electrically connected to the intermediate frequency output port 30P, so as to form a high frequency filter for the intermediate frequency output port 30P, so that the powers of the local oscillation signal and the feedback signal respectively input from the local oscillation signal input port 101P and the feedback signal input port 102P can be all loaded on the two mixing tubes 30P without leaking to the intermediate frequency output port 30P, wherein the two grounded ends of the two mixing tubes 20P are electrically connected to the intermediate frequency output port 30P through two microstrip connection lines 31P having equal electrical length, thereby facilitating cancellation of noise current in the doppler intermediate frequency signal, and thus the balanced mixer presents advantages of low noise and high sensitivity.

In particular, based on the principle of the equivalent circuit of the balanced mixer, the structural form of the balanced mixer has a plurality of variants, the main difference of which lies in the structural variant of the annular bridge 10P, in particular, as shown in fig. 3 to 10 of the drawings of the present specification, the different structures of the annular bridge 10P are illustrated, wherein fig. 3 to 9 illustrate typical two-branch bridges, three-branch bridges, variable resistance bridges, annular two-branch variable resistance bridges, annular bridges, broadband annular bridges, 180 ° hybrid annular bridges, respectively, which are conventional in the industry, wherein based on the variant or combined variant of the different embodiments of the annular bridge 10P illustrated in fig. 3 to 9, the particular embodiment of the annular bridge 10P is flexible, based on the variant or combined variant of the different embodiments of the annular bridge 10P illustrated in fig. 3 to 9, corresponding to fig. 10, a structure of a balanced mixer applied to the conventional doppler microwave detection module is illustrated, although the specific implementation of the ring bridge 10P is flexible and variable, the corresponding equivalent circuit structure does not depart from the equivalent circuit principle illustrated in fig. 1, and the interference rejection capability of the balanced mixer under the condition of satisfying impedance matching still needs to be improved. Referring specifically to fig. 11 and 12 of the drawings in the specification of the present invention, based on the structural configuration of the balanced mixer illustrated in fig. 10, the balanced mixer is designed to be impedance-matched at the operating frequency of the ISM band of 5.8GHz, and the frequency-selecting characteristic diagram and the anti-interference test diagram of the balanced mixer under the condition of satisfying impedance matching are respectively illustrated. Corresponding to fig. 11, based on the characterization of the reflection coefficients of the local oscillator signal input port 101P and the feedback signal input port 102P by the S11 curve and the S22 curve, the loss of the balanced mixer at the 5.8GHz frequency point is significantly reduced to exhibit frequency selection characteristics, but on one hand, the loss of the balanced mixer at the 5.8GHz frequency point is only lower than-10 dB, and therefore is not ideal (generally required to be lower than-20 dB) and is difficult to ensure the doppler intermediate frequency signal output signal strength, and on the other hand, the loss of the balanced mixer in the frequency range lower than 3GHz is still lower than-5 dB and is difficult to resist the electromagnetic radiation interference in the frequency range lower than 3GHz, so that it is difficult to ensure the feedback accuracy of the doppler intermediate frequency signal on the movement of the object in the detection space in the now increasingly complex electromagnetic environment. Specifically, corresponding to fig. 12, an interference test is performed on the doppler intermediate frequency signal output by the balanced mixer based on a dynamic simulation of transmitting an interference signal in a frequency range from 80MHz to 6GHz (corresponding to a frequency range specified by the radiation immunity test of the IEC61000-4-3/GB T17626.3 latest standard), where the doppler intermediate frequency signal under the interference signal of a section of frequency is illustrated by a screenshot, and an amplitude change generated by the doppler intermediate frequency signal due to the interference of the interference signal of the section of frequency on the balanced mixer exceeds even 54.4 mV.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a doppler microwave detection module, wherein doppler microwave detection module includes a microstrip mixer, wherein the S11 curve and the S22 curve of microstrip mixer present obvious narrow trough at the work frequency channel corresponding with corresponding local oscillator signal frequency, correspond the microstrip mixer is in the work frequency channel has lower loss and the frequency bandwidth by the narrowing, and is corresponding the microstrip mixer in the frequency selection characteristic of work frequency channel is excellent and can ensure corresponding doppler intermediate frequency signal' S output signal intensity.

Another object of the present invention is to provide a doppler microwave detection module, wherein the S11 curve and S22 curve of microstrip mixer tend to be gentle and have higher loss at non-working frequency band, namely the S11 curve and S22 curve of microstrip mixer are only in the working frequency band presents obvious narrow trough, corresponds the microstrip mixer is only in the working frequency band has lower loss and the frequency bandwidth who is narrowed, and is corresponding the frequency selection characteristic of microstrip mixer is excellent and can ensure doppler intermediate frequency signal' S output signal intensity and interference killing feature, and then be favorable to improving the feedback precision of doppler intermediate frequency signal to the motion of the object in the corresponding detection space.

Another object of the present invention is to provide a doppler microwave detection module, wherein the feedback accuracy of the motion of the object in the doppler intermediate frequency signal to the corresponding detection space is improved, and is then corresponding the doppler microwave detection module is suitable for the combined detection of the movement characteristics such as the movement, the fine motion, the respiration and the heartbeat of the human body.

Another object of the present invention is to provide a doppler microwave detection module, wherein the microstrip mixer is only in the working frequency band has lower loss and narrowed frequency bandwidth, then based on IEC61000-4-3/GB T17626.3 standard the radiation immunity test will not in the doppler intermediate frequency signal produce exceed the amplitude change that the standard is limited, correspondingly the doppler microwave detection module can be favorable to the popularization of doppler microwave detection module and the promotion of commercial competitiveness in the doppler microwave detection field through the radiation immunity test of IEC61000-4-3/GB T17626.3 standard.

Another object of the present invention is to provide a doppler microwave detection module, wherein the microstrip mixer includes a bridge, wherein the impedance characteristic of the bridge is maintained by suppressing the transient mode of the electrical signal in the bridge, which is ensured to form a pair while the impedance matching of the microstrip mixer is designed, the microstrip mixer is only in the working frequency band presents lower loss and narrowed frequency bandwidth.

Another object of the present invention is to provide a doppler microwave detection module, wherein the electric signal transient in the bridge can be suppressed, then the bridge is required to be reduced to the high-frequency low-loss characteristic of its carrier, correspondingly the bridge is adapted to be carried by the ordinary circuit board substrate, so as to be favorable to reducing the cost of doppler microwave detection module and simplifying the production process of doppler microwave detection module by avoiding using the microwave special circuit board substrate with high-frequency low-loss characteristic.

Another object of the present invention is to provide a doppler microwave detection module, wherein the bridge includes a current suppressing element disposed in a device form and a microstrip mixing line disposed in a microstrip line form and connected between two ends of the current suppressing element, wherein the current suppressing element is disposed in a resistive element or a high frequency inductive element form to have a transient suppression characteristic for an electrical signal, and is capable of maintaining a state in which an impedance characteristic of the bridge matches an impedance characteristic of the microstrip mixing line under the action of the local oscillator signal of a high frequency, in a manner of connecting the current suppressing element between two ends of the microstrip mixing line, in a state in which the impedance characteristic of the bridge is maintained, to suppress the electrical signal of the transient in the bridge, the frequency selection characteristic of the microstrip mixer is improved while the impedance matching design of the microstrip mixer is ensured.

Another object of the present invention is to provide a doppler microwave detection module, wherein the current suppressing element is set to the state of the resistor element, and the resistor element preferably adopts a zero-ohm resistor element to avoid forming a change to the impedance characteristic of the bridge while suppressing the transient electric signal in the bridge, thereby further facilitating to maintain the impedance characteristic of the bridge to match with the impedance characteristic of the microstrip mixing line under the action of the local oscillator signal at a high frequency.

Another object of the present invention is to provide a doppler microwave detection module, wherein the microstrip mixer further includes two mixing pipes and an intermediate frequency output port located on the microstrip mixing line, wherein the microstrip mixing line has a first mixing port sequentially from one end thereof, a local oscillation signal input port adapted to input a local oscillation signal, a feedback signal input port adapted to output a local oscillation signal and input a feedback signal, and a second mixing port having a first microstrip mixing arm defined between the one end and the first mixing port, a second microstrip mixing arm defined between the first mixing port and the local oscillation signal input port, a third microstrip mixing arm defined between the local oscillation signal input port and the feedback signal input port, a fourth microstrip mixing arm defined between the feedback signal input port and the second mixing port, and a fifth microstrip mixing arm defined between said second mixing port and the other end, such that a state is formed in which both ends of said current suppressing element are connected to said first mixing port via said first microstrip mixing arm and to said second mixing port via said fifth microstrip mixing arm, respectively, in a state in which said current suppressing element is connected between both ends of said microstrip mixing line, wherein said second microstrip mixing arm and said fourth microstrip mixing arm have equal-length electrical lengths, and said third microstrip mixing arm has equal-length electrical lengths of one-eighth wavelength or more and equal-half wavelength electrical lengths, respectively, wherein both ends having different polarities belonging to different ones of said mixing pipes are connected to said first mixing port and said second mixing port, respectively, and the other ends having different polarities belonging to different ones of said mixing pipes are grounded, and a high-frequency filter circuit formed by a line of which the first frequency mixing port is grounded through one of the frequency mixing tubes and a line of which the second frequency mixing port is grounded through the other frequency mixing tube is formed between the first frequency mixing port and the second frequency mixing port by ensuring that the high frequencies at the two ends are short-circuited to the ground, so that the power of the local oscillation signal and the power of the feedback signal respectively input from the local oscillation signal input port and the feedback signal input port can be completely loaded on the two frequency mixing tubes and cannot be leaked to the intermediate frequency output port.

Another object of the present invention is to provide a doppler microwave detection module, wherein the first microstrip mixing arm and the fifth microstrip mixing arm have equal length of electricity, correspond the first mixing port with the second mixing port with connection between the current suppression component has equal length of electricity, so in order to be favorable to the cancellation of noise current in the doppler intermediate frequency signal and can remove the intermediate frequency delivery outlet in position on the microstrip mixing line is injectd, and is corresponding the wiring mode of microstrip mixer is various and can be adapted to different circuit layout demands, is favorable to improving simultaneously the doppler intermediate frequency signal is to the feedback precision of the motion of the object in the corresponding detection space.

Another object of the utility model is to provide a doppler microwave detection module, wherein two divide in the mixing pipe and belong to the difference the mixing pipe have not both ends of polarity respectively by isoelectric length connect in first mixing port with the second mixing port, in order to be connected respectively in this both ends first mixing port with the state of second mixing port, the guarantee first mixing port with second mixing port with the connection between the current suppression component has isometric electric length, and then is favorable to the guarantee the feedback precision of doppler intermediate frequency signal to the motion of the object in the corresponding detection space.

Another object of the present invention is to provide a doppler microwave detection module, wherein two the mixing tube is divided into different polarity two ends of the mixing tube are respectively connected to the first microstrip mixing arm in a manner of being connected to the first mixing port and to the fifth microstrip mixing arm in a manner of being connected to the second mixing port, so as to facilitate simplification of the structural design of the microstrip mixer.

Another object of the present invention is to provide a doppler microwave detection module, wherein the intermediate frequency output port is preferably located at the middle position of the third microstrip mixing arm, and two sections bounded by the intermediate frequency output port on the third microstrip mixing arm have equal electrical length, so as to avoid the influence of the non-equal electrical length connection between the first mixing port and the second mixing port and the current suppressing element on the doppler intermediate frequency signal caused by the error generated in the manufacturing process of the microstrip mixing line and the assembling process of the current suppressing element and the mixing tube, and reduce the accuracy requirements on the manufacturing process of the microstrip mixing line and the assembling process of the current suppressing element and the mixing tube while ensuring the feedback accuracy of the doppler intermediate frequency signal on the movement of the object in the corresponding detection space, therefore, the method is simple and easy to implement and has low cost.

Another object of the present invention is to provide a doppler microwave probe module, wherein the connection circuit between the two mixing tubes and the first mixing port and the second mixing port is located in the region defined by the sequential connection lines of the local oscillation signal input port, the first mixing port, the second mixing port and the feedback signal input port, to reduce the size of the space occupied by the microstrip mixer and to increase the amount of angular jump in the connection line between the two mixer tubes and the first and second mixer ports with respect to the second and fourth microstrip mixer arms in the extension direction, thereby facilitating further suppression of transient electrical signals in the bridge acting in parallel with the current suppressing element in a state in which the impedance characteristics of the microstrip mixing line are maintained, and correspondingly ensuring the feedback precision of the Doppler intermediate frequency signal to the motion of the object in the corresponding detection space.

Another object of the present invention is to provide a doppler microwave detection module, wherein at least one metal patch is connected to the high frequency filter circuit is right with being suitable for through and ground between form distributed capacitance's mode formation the promotion of high frequency filter circuit's high frequency filter characteristic corresponds the promotion the frequency selection characteristic of microstrip mixer is favorable to improving the feedback precision of doppler intermediate frequency signal to the motion of the object in the corresponding detection space.

Another object of the present invention is to provide a doppler microwave detection module, wherein the third microstrip mixing arm is bent to be set up, so as to be able to further reduce the space size that the microstrip mixer occupies under the restriction that the third microstrip mixing arm has electrical length of more than or equal to one-eighth wavelength and electrical length of less than or equal to one-half wavelength.

Another object of the present invention is to provide a doppler microwave detection module, wherein the microstrip mixing line is configured with a central line of the connection line of the first mixing port and the second mixing port symmetrical, so as to satisfy each of the electrical length relationships between the microstrip mixing arms based on a simple form design of the microstrip mixing line, thereby being easy to implement.

Another object of the present invention is to provide a doppler microwave detection module, wherein the doppler microwave detection module further includes a local oscillator circuit and an antenna, wherein the local oscillator circuit is set up to allow to be powered and output the local oscillator signal, and by feed connection in the microstrip mixer the local oscillator signal input port, wherein the antenna by feed connection in the microstrip mixer the feedback signal input port, so that the antenna can pass through the microstrip mixer by local oscillator signal feed and input the feedback signal extremely the microstrip mixer, correspond based on the above-mentioned structural principle of microstrip mixer improves the detection precision of doppler microwave detection module to the motion of the object in the corresponding detection space.

Another object of the present invention is to provide a doppler microwave detection module, wherein the detection accuracy of the doppler microwave detection module is improved and is suitable for the combined detection of the movement, the fine movement, the respiration, and the heartbeat of the human body.

According to an aspect of the utility model, the utility model provides a Doppler microwave detection module, Doppler microwave detection module includes:

a local oscillator circuit, wherein the local oscillator circuit is configured to be enabled to be powered on and output a local oscillator signal;

an antenna, wherein the antenna comprises a reference ground and a radiation source spaced from the reference ground to equivalently form an open capacitor capable of receiving a feedback signal in an electromagnetic environment; and

a microstrip mixer, wherein said microstrip mixer comprises:

a bridge, wherein the bridge comprises a current suppressing element and a microstrip mixing line, wherein the current suppressing element is provided as a resistive element or a high-frequency inductive element in the form of a component and is connected between both ends of the microstrip mixing line, wherein the microstrip mixing line has, in order from one end thereof, a first mixing port, a local oscillation signal input port adapted to the local oscillation signal input, a feedback signal input port adapted to the feedback signal input, and a second mixing port, having, in correspondence with the microstrip mixing line, a first microstrip mixing arm defined between the one end and the first mixing port, a second microstrip mixing arm defined between the first mixing port and the local oscillation signal input port, a third microstrip mixing arm defined between the first mixing port and the local oscillation signal input port, a fourth microstrip mixing arm defined between the feedback signal input port and the second mixing port, and a fifth microstrip mixing arm defined between the second mixing port and another end, wherein the second microstrip mixing arm and the fourth microstrip mixing arm have equal electrical lengths, and the third microstrip mixing arm has an electrical length greater than or equal to one-eighth wavelength and less than or equal to one-half wavelength, wherein the local oscillator signal input port is fed to the local oscillator circuit and is switched in the local oscillator signal in a state where the local oscillator circuit is powered, wherein the radiation source is fed to the feedback signal input port and is fed by the local oscillator signal and inputs the feedback signal to the microstrip mixer;

two mixing tubes, wherein two ends of the two mixing tubes with different polarities are respectively connected to the first mixing port and the second mixing port, and the other two ends of the two mixing tubes with different polarities are grounded;

an intermediate frequency output port, wherein the intermediate frequency output port is located on the microstrip mixing line, so as to output a doppler intermediate frequency signal corresponding to a frequency/phase difference between the local oscillator signal and the feedback signal at the intermediate frequency output port in a state where the local oscillator signal is input at the local oscillator signal input port and the feedback signal is input at the feedback signal input port.

In one embodiment, the feed connection between the radiation source and the feedback signal input port is an open circuit connection coupled through a corresponding capacitor.

In one embodiment, the feed connection between the local oscillator circuit and the feedback signal input port is an open circuit connection coupled through a corresponding capacitor.

In an embodiment, wherein the first microstrip mixing arm and the fifth microstrip mixing arm are arranged with equal electrical lengths.

In an embodiment, the connections between the two ends of the two mixing pipes connected to the first mixing port and the second mixing port and the corresponding first mixing port and the second mixing port have equal electrical lengths.

In one embodiment, the microstrip mixer further comprises a ground patch, wherein the ground patch is grounded in a state of being connected to the reference ground, and wherein two ends of the two mixer tubes that are grounded in a state of being connected to the ground patch.

In an embodiment, the third microstrip mixing arm is folded.

In one embodiment, the intermediate frequency output port is located at a middle position of the third microstrip mixing arm.

In an embodiment, the microstrip mixing lines are arranged symmetrically to a midline of a connection of the first and second mixing ports.

In an embodiment, two of the mixing transistors are arranged in a diode form, wherein two ends of the two diodes with different polarities belonging to different diodes are respectively connected to the first mixing port and the second mixing port, an anode of one of the diodes is connected to the second mixing port, and a cathode of the other diode is connected to the first mixing port.

In an embodiment, a connection line between two of the mixing pipes and the first and second mixing ports is located in a ring region defined by a connection line between the first and second mixing ports and the second, third and fourth microstrip mixing arms.

Further objects and advantages of the invention will be fully apparent from the ensuing description and drawings.

These and other objects, features and advantages of the present invention will become more fully apparent from the following detailed description, the accompanying drawings and the appended claims.

Drawings

Fig. 1 is a schematic diagram of an equivalent circuit of a conventional balanced mixer.

Fig. 2 is a schematic diagram of a microstrip structure of a conventional microstrip balanced mixer using a two-branch 3dB bridge based on the equivalent circuit principle of the conventional balanced mixer.

Fig. 3 is a schematic diagram of a microstrip structure of a conventional two-branch bridge based on the equivalent circuit principle of a conventional balanced mixer.

Fig. 4 is a schematic diagram of a microstrip structure of a three-branch bridge based on the equivalent circuit principle of the prior balanced mixer.

Fig. 5 is a schematic diagram of a microstrip structure of a variable resistance bridge based on the equivalent circuit principle of a conventional balanced mixer.

Fig. 6 is a schematic diagram of a microstrip structure of a circular two-branch variable resistance bridge based on the equivalent circuit principle of the prior balanced mixer.

Fig. 7 is a schematic diagram of a microstrip structure of a ring bridge based on the equivalent circuit principle of a conventional balanced mixer.

Fig. 8 is a schematic diagram of a microstrip structure of a broadband ring bridge based on the equivalent circuit principle of a conventional balanced mixer.

Fig. 9 is a schematic diagram of a microstrip structure of a 180 ° hybrid ring bridge based on the equivalent circuit principle of a conventional balanced mixer.

Fig. 10 is a schematic diagram of another balanced mixer based on the equivalent circuit principle of the prior balanced mixer.

Fig. 11 is a frequency selection characteristic diagram of the balanced mixer under the condition of satisfying impedance matching.

Fig. 12 is an anti-interference test chart of the balanced mixer under the condition of satisfying impedance matching.

Fig. 13 is a schematic diagram illustrating an equivalent circuit of a microstrip mixer according to an embodiment of the present invention.

Fig. 14A is a schematic diagram of a microstrip structure of the microstrip mixer according to the present invention based on the equivalent circuit principle of the above embodiment.

Fig. 14B is a schematic diagram of a microstrip structure variation of the microstrip mixer according to the present invention based on the equivalent circuit principle of the above embodiment.

Fig. 15A is a schematic diagram of another microstrip structure of the microstrip mixer according to the present invention based on the equivalent circuit principle of the above embodiment.

Fig. 15B is a schematic diagram of a microstrip structure variation of the microstrip mixer according to the present invention based on the equivalent circuit principle of the above embodiment.

Fig. 16A is a schematic diagram of another microstrip structure of the microstrip mixer according to the present invention based on the equivalent circuit principle of the above embodiment.

Fig. 16B is a schematic diagram of a microstrip structure variation of the microstrip mixer according to the present invention based on the equivalent circuit principle of the above embodiment.

Fig. 16C is a schematic diagram of a microstrip structure variation of the microstrip mixer according to the present invention based on the equivalent circuit principle of the above embodiment.

Fig. 17 is a frequency-selecting characteristic diagram of the microstrip mixer according to the present invention based on the equivalent circuit principle of the above embodiment, under the condition of satisfying impedance matching.

Fig. 18 is an anti-interference test chart of the microstrip mixer according to the present invention based on the equivalent circuit principle of the above embodiment, under the condition of satisfying impedance matching.

Fig. 19 is an equivalent circuit schematic diagram of a doppler microwave detection module with the microstrip mixer according to the present invention.

Detailed Description

The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art. The basic principles of the invention, as defined in the following description, may be applied to other embodiments, variations, modifications, equivalents and other technical solutions without departing from the spirit and scope of the invention.

It will be understood by those skilled in the art that in the present disclosure, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in a generic and descriptive sense only and not for purposes of limitation, as the terms are used in the description to indicate that the referenced device or element must have the specified orientation, be constructed and operated in the specified orientation, and not for the purpose of limitation.

It is understood that the terms "a" and "an" should be interpreted as meaning that a number of one element or element is one in one embodiment, while a number of other elements is one in another embodiment, and the terms "a" and "an" should not be interpreted as limiting the number.

The utility model provides a Doppler microwave detection module, wherein Doppler microwave detection module is suitable for the warp the microstrip mixer is by a local oscillator signal feed and corresponding to in corresponding detection space transmission a detection beam of local oscillator signal frequency, and receipt the detection beam is in detection space is received a echo and is received a repayment signal by the formation of an at least object reflection, wherein the mixer is received repayment signal and with the mode output of mixing detection corresponding to local oscillator signal with a Doppler intermediate frequency signal of the frequency difference between the repayment signal then based on the Doppler effect principle, the fluctuation of Doppler intermediate frequency signal on the range theoretically corresponds to the motion of the object in the detection space.

Referring to fig. 13 to 16C of the drawings attached to the present specification, the equivalent circuit principle of the microstrip mixer and the structure of the microstrip mixer based on different embodiments of the equivalent circuit principle of the present invention are respectively illustrated, wherein the balanced mixer includes a bridge 10, two mixing pipes 20 and an intermediate frequency output port 30, wherein the bridge 10 includes a current suppressing element 11 disposed in a component form and a microstrip mixing line 12 disposed in a microstrip line form and connected between two ends of the current suppressing element 11, wherein the current suppressing element 11 is disposed in a resistive element or a high frequency inductive element form and has a transient suppression characteristic for an electrical signal, and the microstrip mixing line 12 distinguished from the microstrip line form in a resistive or inductive characteristic under a high frequency electrical signal and can maintain an impedance characteristic of the bridge 10 and a resistance characteristic of the microstrip mixing line 12 under a high frequency local oscillator signal action The impedance matching state is such that the current suppressing element 11 is connected between the two ends of the microstrip mixer line 12, so that transient electric signals in the bridge 10 are suppressed while maintaining the impedance characteristics of the bridge 10, and the frequency selection characteristics of the microstrip mixer are improved while ensuring the impedance matching design of the microstrip mixer.

Specifically, the if output port 30 is located on the microstrip mixing line 12, wherein the microstrip mixing line 12 has a first mixing port 1201, a local oscillator input port 1202 adapted to the local oscillator input signal, a feedback signal input port 1203 adapted to the local oscillator output signal and the feedback signal input port, and a second mixing port 1204 sequentially from one end thereof, a first microstrip mixing arm 121 defined between the one end and the first mixing port 1201 corresponding to the microstrip mixing line 12, a second microstrip mixing arm 122 defined between the first mixing port 1201 and the local oscillator input port 1202, a third microstrip mixing arm 123 defined between the local oscillator input port 1202 and the feedback signal input port 1203, a fourth microstrip mixing arm 124 defined between the feedback signal input port 1203 and the second mixing port 1204, and a fifth microstrip mixing arm 125 defined between the second mixing port 1204 and the other end, such that a state in which both ends of the current suppressing element 11 are connected to the first mixing port 1201 via the first microstrip mixing arm 121 and the second mixing port 1204 via the fifth microstrip mixing arm 125, respectively, is formed in a state in which the current suppressing element 11 is connected between both ends of the microstrip mixing line 12, corresponding to a connection relationship with a bridge function between the current suppressing element 11 and the microstrip mixing line 12, wherein the second microstrip mixing arm 122 and the fourth microstrip mixing arm 124 have equal length of electricity, and the third microstrip mixing arm 123 has equal or more than one eighth wavelength of electricity and equal or less than one half wavelength of electricity, wherein both ends of the two mixing tubes 20 having different polarities are connected to the first mixing port 20, respectively And the second mixing port 1204, the other two ends of the two mixing tubes 20 with different polarities are grounded to ensure that the high frequencies of the two ends are short-circuited to ground, so as to form a high-frequency filter circuit between the first mixing port 1201 and the second mixing port 1204, the high-frequency filter circuit being formed by a line connected to ground through one of the mixing tubes 20 at the first mixing port 1201 and a line connected to ground through the other mixing tube 20 at the second mixing port 1204, so that the powers of the local oscillation signal and the feedback signal respectively input from the local oscillation signal input port 1202 and the feedback signal input port 1203 can be all applied to the two mixing tubes 20 without leaking to the intermediate frequency output port 30.

Preferably, in the embodiments of the present invention, two of the mixing tubes 20 are disposed in a diode form, and the connection structure of the two diodes, in which two ends of the diodes having different polarities are respectively connected to the first mixing port 1201 and the second mixing port 1204, specifically corresponds to: the anode of one of the diodes is connected to the second mixing port 1204, and the cathode of the other diode is connected to the first mixing port 1201, so as to improve the mixing efficiency of the microstrip mixer.

It is worth mentioning that in the state where the current suppressing element 11 is set as the resistive element, the resistive element preferably adopts a zero-ohm resistive element to suppress the transient electrical signal in the bridge 10 while avoiding the change of the impedance characteristic of the bridge 10, thereby further facilitating to maintain the impedance characteristic of the bridge 10 to match the impedance characteristic of the microstrip mixing line 12 under the action of the local oscillator signal of high frequency.

In particular, the first microstrip mixing arm 121 and the fifth microstrip mixing arm 125 are preferably configured to have equal electrical lengths, and the first mixing port 1201 and the second mixing port 1204 are electrically connected to the current suppressing element 11 by equal electrical lengths, so as to facilitate cancellation of noise current in the doppler intermediate frequency signal and to release the position limitation of the intermediate frequency output port 30 on the microstrip mixing line 12, and accordingly, the microstrip mixer is diversified in wiring manner to be adaptable to different circuit layout requirements, and at the same time, to facilitate improvement of the feedback accuracy of the doppler intermediate frequency signal to the motion of the object in the corresponding detection space.

Further, two ends of the two mixing tubes 20, which belong to different mixing tubes 20 and have different polarities, are preferably connected to the first mixing port 1201 and the second mixing port 1204 by equal electrical lengths, so that in a state where the two ends are connected to the first mixing port 1201 and the second mixing port 1204, respectively, it is ensured that the connections between the first mixing port 1201 and the second mixing port 1204 and the current suppressing element 11 have equal electrical lengths, and thus, it is favorable for ensuring the feedback accuracy of the doppler intermediate frequency signal on the motion of the object in the corresponding detection space.

In particular, the if output port 30 is preferably located at the middle position of the third microstrip mixing arm 123, and two sections of the third microstrip mixing arm 123 bounded by the if output port 30 have equal electrical lengths, so as to avoid the influence of the non-equal electrical length connection between the first mixing port 1201 and the second mixing port 1204 and the current suppressing element 11 caused by the error generated in the production process of the microstrip mixing line 12 and the assembly process of the current suppressing element 11 and the mixing tube 20 on the doppler if signal, and reduce the accuracy requirements on the production process of the microstrip mixing line 12 and the assembly process of the current suppressing element 11 and the mixing tube 20 while ensuring the feedback accuracy of the doppler if signal on the motion of the object in the corresponding detection space, and thus is simple and easy, the cost is low.

Optionally, the microstrip mixer further includes at least one metal patch 40, where the metal patch 40 is connected to the high-frequency filter circuit to be suitable for forming an enhancement to the high-frequency filter characteristic of the high-frequency filter circuit by forming a distributed capacitance with the ground, and correspondingly enhancing the frequency selection characteristic of the microstrip mixer to facilitate improving the feedback accuracy of the doppler intermediate frequency signal to the motion of the object in the corresponding detection space.

Preferably, in the high frequency filter circuit configured by a line in which the first mixing port 1201 is grounded via one of the mixing tubes 20 and a line in which the second mixing port 1204 is grounded via the other mixing tube 20, at least one of the metal patches 40 is connected to the line in which the first mixing port 1201 is grounded via one of the mixing tubes 20 and the line in which the second mixing port 1204 is grounded via the other mixing tube 20, respectively, thereby further facilitating cancellation of noise current in the doppler intermediate frequency signal.

Further, in the embodiments of the present invention, the connection line between the two mixing pipes 20 and the first mixing port 1201 and the second mixing port 1204 is located in the annular region defined by the connection line between the first mixing port 1201 and the second mixing port 1204 and the second microstrip mixing arm 122, the third microstrip mixing arm 123 and the fourth microstrip mixing arm 124, so as to reduce the size of the space occupied by the microstrip mixer, and to form and intensify the abrupt change of the angle of the connection line between the two mixing pipes 20 and the first mixing port 1201 and the second mixing port 1204 in the extending direction with respect to the second microstrip mixing arm 122 and the fourth microstrip mixing arm 124, thereby facilitating to further suppress transient electric signals in the bridge 10 in parallel with the current suppressing element 11 in a state of maintaining the impedance characteristic of the microstrip mixing line 12, and correspondingly ensuring the feedback precision of the Doppler intermediate frequency signal to the motion of the object in the corresponding detection space.

That is, in some embodiments of the present invention, the connection line between the two mixing pipes 20 and the first mixing port 1201 and the second mixing port 1204 is located in a ring region defined by the connection line between the first mixing port 1201 and the second mixing port 1204 and the second microstrip mixing arm 122, the third microstrip mixing arm 123 and the fourth microstrip mixing arm 124, the current suppressing element 11 may not be disposed, and the first microstrip arm 121 and the fifth microstrip arm 125 are integrally connected corresponding to the ring microstrip line shape formed by the microstrip mixing lines 12 connected end to end in the bridge 10, which is not limited by the present invention.

Specifically, in the embodiments of the present invention, the microstrip mixer further includes a ground patch 50, wherein the ground patch 50 is grounded, two ends of the mixing tubes 20 with different polarities are respectively connected to the first mixing port 1201 and the second mixing port 1204, and the other two ends of the mixing tubes 20 with different polarities are connected to the ground patch 50 and grounded.

It should be noted that the connection between the first mixing port 1201 and the corresponding mixing tube 20 allows a separate microstrip line, which integrally extends from the first mixing port 1201 to the first microstrip arm 121 and the second microstrip arm 122, to be directly connected to the corresponding mixing tube 20, corresponding to fig. 14A and 14B and fig. 16C, or to be connected to the corresponding mixing tube 20 via the first microstrip arm 121, corresponding to fig. 15A to 16B; likewise, the connection between the second mixing port 1204 and the corresponding mixing tube 20 allows the separate microstrip line integrally extended from the second mixing port 1204 to the fourth microstrip arm 124 and the fifth microstrip arm 125 to be directly connected to the corresponding mixing tube 20, or to be connected to the corresponding mixing tube 20 via the fifth microstrip arm 125, corresponding to fig. 15A to 16B, corresponding to fig. 14A and 14B and fig. 16C, without limitation.

That is, corresponding to fig. 15A to 16B, two ends of the two mixing pipes 20 with different polarities of the two mixing pipes 20 are connected to the first mixing port 1201 and the second mixing port 1204 respectively in a manner of being connected to the first microstrip mixing arm 121 and in a manner of being connected to the fifth microstrip mixing arm 125, so as to facilitate simplification of the structural design of the microstrip mixer, and the connection lines of the first microstrip mixing arm 121 and the fifth microstrip mixing arm 125 respectively to the first mixing port 1201 and the second mixing port 1204 and the second microstrip mixing arm 122, the third microstrip mixing arm 123 and the fourth microstrip mixing arm 124 are integrally extended in a ring region defined by the first microstrip mixing arm 121 and the fifth microstrip mixing arm 125 and the second microstrip mixing arm 122, the third microstrip mixing arm 123 and the fourth microstrip mixing arm 124, so as to form the connection lines between the two mixing pipes 20 and the first mixing port and the second mixing port 1204 A state in a ring region defined by the connection line between the first mixing port 1201 and the second mixing port 1204, the second microstrip mixing arm 122, the third microstrip mixing arm 123, and the fourth microstrip mixing arm 124, which is not limited by the present invention.

It is worth mentioning that both ends of the current suppressing element 11 are respectively connected to the first mixing port 1201 and the second mixing port 1204 via the first microstrip mixing arm 121 and the fifth microstrip mixing arm 125, and a state in which two ends of the two mixing transistors 20 having different polarities, which belong to different mixing transistors 20, are connected to the first mixing port 1201 and the second mixing port 1204, respectively, and the other two ends of the two mixing transistors 20 having different polarities, which belong to different mixing transistors 20, are connected to ground, the current suppressing element 11 and the two mixing transistors 20 are connected in parallel between the first mixing port 1201 and the second mixing port 1204, wherein the parallel connection sequence between the current suppressing element 11 and the two mixing tubes 20 between the first mixing port 1201 and the second mixing port 1204 does not constitute a limitation of the present invention.

That is, in some embodiments of the present invention, corresponding to fig. 14A to 16C, two of the mixing pipes 20 are within the ring-shaped area defined by the microstrip mixing line 12 and the bridge 10 formed by the current suppressing element 11 connected between the two ends of the microstrip mixing line 12, while in other embodiments of the present invention, two of the mixing pipes 20 are outside the ring-shaped area defined by the microstrip mixing line 12 and the bridge 10 formed by the current suppressing element 11 connected between the two ends of the microstrip mixing line 12, and are also able to allow the connection lines between two of the mixing pipes 20 and the first and

second mixing ports

1201, 1204 to be located between the first and second mixing ports by increasing the amount of angular protrusion of the first and fifth

microstrip mixing arms

121, 125 relative to the second and fourth

microstrip mixing arms

122, 124 in the extension direction The connection line of the second mixing port 1204 is connected to the second microstrip mixing arm 122, the third microstrip mixing arm 123 and the fourth microstrip mixing arm 124, which are commonly defined in the annular region, and the present invention is not limited thereto.

Further, in the embodiments of the present invention, the third microstrip mixing arm 123 is bent to be able to further reduce the size of the space occupied by the microstrip mixer under the limitation that the third microstrip mixing arm 123 has an electrical length greater than or equal to one-eighth wavelength and less than or equal to one-half wavelength.

In particular, corresponding to fig. 16A to 16C, in the state where the third microstrip mixing arm 123 is bent, the microstrip mixing line 12 is not designed in a bent form at the position of the local oscillator signal input port 1202 defined between the second microstrip mixing arm 122 and the third microstrip mixing arm 123 and at the position of the feedback signal input port 1203 defined between the third microstrip mixing arm 123 and the fourth microstrip mixing arm 124, that is, the local oscillator signal input port 1202 and the feedback signal input port 1203 are different from those of fig. 14A to 15B and are not located at the inflection point of the microstrip mixing line 12, so that, under the restriction that the third microstrip mixing arm 123 has an electrical length equal to or greater than one eighth wavelength and an electrical length equal to or less than one half wavelength, by the bending of the third microstrip mixing arm 123, while reducing the size of the space occupied by the microstrip mixer, the area of a ring-shaped area defined by the connection line of the first mixing port 1201 and the second mixing port 1204, the second microstrip mixing arm 122, the third microstrip mixing arm 123 and the fourth microstrip mixing arm 124 is ensured, so as to facilitate the circuit layout of the two mixing tubes 20 in the ring-shaped area.

Further, in the embodiments illustrated in fig. 14A to 16C, the microstrip mixing line 12 is arranged symmetrically with respect to the central line of the connecting line of the first mixing port 1201 and the second mixing port 1204, so that the electrical length relationship between the microstrip mixing arms can be simultaneously satisfied based on a simple form design of the microstrip mixing line, and thus it is easy to implement.

It is worth mentioning that, based on the equivalent circuit principle of the microstrip mixer of the present invention, the microstrip mixer has various structural configurations, wherein the second microstrip mixing arm 122 and the fourth microstrip mixing arm 124 have equal electrical lengths, and the third microstrip mixing arm 123 has one-eighth wavelength electrical length and one-half wavelength electrical length, and two of the mixing tubes 20 are different, two ends of the mixing tubes 20 with different polarities are respectively connected to the first mixing port 1201 and the second mixing port 1204, two of the mixing tubes 20 are different, the other ends of the mixing tubes with different polarities are grounded, and based on the current suppressing element 11 provided in the form of components and parts connected to the two ends of the microstrip mixing line 12 and/or two of the mixing tubes 20 are connected to the connecting line between the first mixing port 1201 and the second mixing port 1204 The structural design in the ring region defined by the connection line of the first mixing port 1201 and the second mixing port 1204, the second microstrip mixing arm 122, the third microstrip mixing arm 123, and the fourth microstrip mixing arm 124 together can suppress the transient of the electrical signal in the electrical bridge 10 while maintaining the impedance characteristic of the electrical bridge 10, and correspondingly, the impedance matching design of the microstrip mixer is ensured while improving the frequency selection characteristic of the microstrip mixer, and accordingly, the microstrip mixer has low loss and a narrowed bandwidth only in the working frequency band corresponding to the local oscillator signal frequency, so that the output signal strength and the anti-interference performance of the intermediate frequency signal can be ensured, and the feedback accuracy of the doppler intermediate frequency signal on the motion of the object in the corresponding detection space can be further improved.

Referring specifically to fig. 17 and 18 of the drawings accompanying the description of the present invention, based on the structural form of the balanced mixer illustrated in fig. 16A, the balanced mixer is designed to be impedance-matched with the operating frequency band of the ISM frequency band of 5.8GHz, and the frequency selection characteristic diagram and the anti-interference test diagram of the balanced mixer under the condition of satisfying impedance matching are respectively illustrated.

Corresponding to fig. 17, based on the characterization of the reflection coefficients of the local oscillator signal input port 1202 and the feedback signal input port 1203 by the curves S11 and S22, the balanced mixer exhibits an obvious narrow trough at the working frequency band of 5.8GHz, and the microstrip mixer has a lower loss and a narrowed bandwidth at the working frequency band, so that the frequency selection characteristic of the microstrip mixer at the working frequency band is excellent, and the output signal strength of the corresponding doppler intermediate frequency signal can be ensured.

Furthermore, the S11 curve and the S22 curve of the microstrip mixer tend to be flat and have high loss in the non-working frequency band, that is, the S11 curve and the S22 curve of the microstrip mixer are only in the working frequency band showing obvious narrow troughs, and the microstrip mixer is only in the working frequency band having low loss and narrowed frequency bandwidth, so that the microstrip mixer has excellent frequency selection characteristics, and can ensure the output signal strength and the anti-interference performance of the doppler intermediate frequency signal, thereby being beneficial to improving the feedback accuracy of the doppler intermediate frequency signal to the motion of the object in the corresponding detection space.

Corresponding to fig. 18, based on a dynamic analog test of transmitting an interference signal in the frequency range of 80MHz to 6GHz (corresponding to the frequency range specified by the radiation immunity test of the latest standard of IEC61000-4-3/GB T17626.3) to the doppler intermediate frequency signal output by the balanced mixer, the doppler intermediate frequency signal under the interference signal of one section of frequency is shown by the screenshot, wherein the interference of the interference signal of the section of frequency to the balanced mixer does not generate obvious amplitude change in the doppler intermediate frequency signal, and the doppler intermediate frequency signal tends to be flat correspondingly, the corresponding Doppler microwave detection module can pass the radiation immunity test of IEC61000-4-3/GB T17626.3 standard, which is beneficial to the popularization of the Doppler microwave detection module and the promotion of commercial competitiveness in the Doppler microwave detection field.

With further reference to fig. 19 of the drawings accompanying the present specification, the equivalent circuit principle of the doppler microwave detection module with the microstrip mixer is illustrated, wherein the doppler microwave detection module further comprises a local oscillator circuit 60 and an antenna 70, wherein the local oscillator circuit 60 is arranged to be powered to output the local oscillator signal and is fed to the local oscillator signal input port 1202 of the microstrip mixer, wherein the antenna 70 is fed connected to the feedback signal input port 1203 of the microstrip mixer, such that the antenna 70 can be fed by the local oscillator signal via the microstrip mixer and input the feedback signal to the microstrip mixer, the detection precision of the Doppler microwave detection module on the motion of the object in the corresponding detection space is improved correspondingly based on the structural principle of the microstrip mixer.

It should be noted that the feeding connection between the local oscillator circuit 60 and the feedback signal input port 1203 of the microstrip mixer and the feeding connection between the antenna 70 and the feedback signal input port 1203 of the microstrip mixer are via connections under the action of high-frequency electrical signals, so that the feeding connection between the local oscillator circuit 60 and the feedback signal input port 1203 of the microstrip mixer and the feeding connection between the antenna 70 and the feedback signal input port 1203 of the microstrip mixer are in via connections allowed to be directly connected in a physical circuit or in open connections coupled via corresponding capacitors (such as microstrip coupling capacitors, distributed capacitors and capacitive elements), which is not limited by the present invention.

Preferably, the feeding connection between the antenna 70 and the feedback signal input port 1203 of the microstrip mixer is an open circuit connection configuration coupled by a corresponding capacitor in a physical circuit, so as to further improve the anti-interference performance of the doppler microwave detection module while ensuring the stability of the doppler microwave detection module by the high impedance characteristic of the capacitor to the low frequency signal and the isolation characteristic to the direct current signal.

Optionally, the feed connection between the local oscillator circuit 60 and the feedback signal input port 1203 of the microstrip mixer is an open circuit connection state in which the physical circuit is coupled by a corresponding capacitor, so that the stability of the doppler microwave detection module is guaranteed and the anti-interference performance of the doppler microwave detection module is further improved through the high impedance characteristic of the capacitor to the low frequency signal and the isolation characteristic to the direct current signal.

Further, the antenna 70 includes a reference ground and a radiation source spaced from the reference ground to equivalently form an open capacitor C₀Capable of generating the feedback signal in an electromagnetic environment, wherein the radiation source is fed to the feedback signal input port 1203 of the microstrip mixer to form a feeding connection relationship between the antenna 70 and the feedback signal input port 1203, wherein the reference ground is grounded and is equivalent to an equivalent capacitor C in fig. 19₀Corresponding to the radiation source equivalent to the open capacitor C in fig. 19₀The ground patch 50 is grounded in a state of being connected to the reference ground, and in a state of being connected to the metal patch 40, the metal patch 40 is capable of forming a distributed capacitance with the reference ground to improve a high-frequency filter characteristic of the high-frequency filter circuit.

It is worth mentioning that in the description of the present invention, wherein due to the existence of industrial errors, the relationship description and limitation based on the electrical length is allowed to have an error range of 20% in the actual measurement, for example, "the second microstrip mixing arm 122 and the fourth microstrip mixing arm 124 have equal electrical lengths, and the third microstrip mixing arm 123 has an electrical length greater than or equal to one eighth wavelength and less than or equal to one half wavelength" should be understood as: the second microstrip mixing arm 122 and the fourth microstrip mixing arm 124 have equal electrical lengths within a tolerance range of 20%, and the third microstrip mixing arm 123 has an electrical length greater than or equal to one eighth wavelength and less than or equal to one half wavelength within a tolerance range of 20%.

It will be appreciated by persons skilled in the art that the above embodiments are only examples, wherein features of different embodiments may be combined with each other to obtain embodiments which are easily conceivable according to the present disclosure, but which are not explicitly indicated in the drawings, and the present disclosure is not limited thereto.

It will be understood by those skilled in the art that the embodiments of the present invention as described above and shown in the drawings are given by way of example only and are not limiting of the present invention. The objects of the present invention have been fully and effectively accomplished. The functional and structural principles of the present invention have been shown and described in the embodiments without departing from the principles, embodiments of the present invention may have any deformation or modification.

Claims

1. A doppler microwave detection module, comprising:

a microstrip mixer, wherein said microstrip mixer comprises:

2. The doppler microwave detection module of claim 1, wherein the feed connection between the radiation source and the feedback signal input port is physically disconnected by a corresponding capacitive coupling.

3. The doppler microwave detection module of claim 2, wherein the feed connection between the local oscillator circuit and the feedback signal input port is physically an open circuit connection coupled via a corresponding capacitor.

4. Doppler microwave detection module according to claim 3, wherein the first and fifth microstrip mixing arms are arranged with equal electrical lengths.

5. Doppler microwave detection module according to claim 4, wherein the connections between the two ends of the two mixing tubes connected to the first and second mixing ports and the respective first and second mixing ports have equal electrical lengths.

6. The doppler microwave detection module according to claim 5, wherein the microstrip mixer further comprises a ground patch, wherein the ground patch is grounded in a state of being connected to the reference ground, and wherein both ends of the two mixer tubes that are grounded in a state of being connected to the ground patch.

7. Doppler microwave detection module according to claim 6, wherein the third microstrip mixing arm is meander-arranged.

8. Doppler microwave detection module according to claim 7, wherein the intermediate frequency output port is located at a middle position of the third microstrip mixing arm.

9. Doppler microwave detection module according to claim 8, wherein the microstrip mixing lines are arranged symmetrically to a middle line of a connection of the first and second mixing ports.

10. The doppler microwave detection module according to claim 9, wherein the two mixing tubes are arranged in a diode form, wherein two ends of the two diodes having different polarities, which belong to different diodes, are respectively connected to the first mixing port and the second mixing port, wherein an anode of one of the diodes is connected to the second mixing port, and a cathode of the other diode is connected to the first mixing port.

11. A doppler microwave detection module according to any one of claims 1 to 10, wherein a connection line between the two mixing tubes and the first and second mixing ports is located within a ring region defined by a connection line between the first and second mixing ports and the second, third and fourth microstrip mixing arms.