CN117889892B - Variable-capacitance microwave direct-drive variable-frequency sensor, system and control method - Google Patents

Abstract

The invention discloses a variable capacitance microwave direct-drive variable frequency sensor, a system and a control method. The variable capacitance microwave direct-drive variable frequency sensor system provided by the invention can enable a single transceiver gateway to accept, identify and restore the measured data of the corresponding variable capacitance microwave direct-drive variable frequency sensor, and solves the problems that in the prior art, too few sampling points are acquired by arranging a single transceiver gateway at the same position, and the monitoring of equipment or environment is not facilitated.

Description

A variable capacitance microwave direct-drive frequency conversion sensor, system and control method

Technical Field

The present invention relates to the field of wireless communication technology, and more specifically, to a variable capacitance microwave direct-driven variable frequency sensor, system and control method.

Background technique

Microwave Driven Frequency Conversion (MDFC) technology has the characteristics of wireless communication and no need for power supply. When used in sensors, variable capacitance microwave direct-driven frequency conversion sensors have the advantages of easy layout and meeting the working requirements in multiple scenarios.

The transceiver gateway in the existing MDFC system is limited by the problem of consistent driven return frequency of MDFC sensors, which makes it difficult to form an MDFC sensor network. As a result, a single transceiver gateway carries too few MDFC sensors, and a single transceiver gateway arranged at the same location obtains too few sampling points, which is not conducive to large-scale applications. In order for the transceiver to be able to identify different MDFC sensor signals, the driven return frequencies of different MDFC sensors need to be differentiated, but the resonators used by existing MDFC sensors to adjust the driven return frequency are limited in frequency and type. Replacing the resonator alone to differentiate the driven return frequencies of different MDFC sensors is limited by the insufficient number of resonator models, and there are not many variable frequencies. This has led to the number of sensors under the same transceiver gateway being always limited.

Summary of the invention

The present invention overcomes the shortcomings of the prior art and provides a variable capacitance microwave direct-driven frequency conversion sensor, system and control method to solve the problem of limited number of sensors under the same transceiver gateway in the prior art.

In order to solve the above technical problems, one aspect of the present invention provides a variable capacitance microwave direct-driven variable frequency sensor;

A variable capacitance microwave direct-driven frequency conversion sensor, comprising an antenna network, a matching network, a resonance network, and a frequency conversion network;

The antenna network is used to receive the driving signal sent by the transceiver gateway and the driven return signal after the return sensor completes the frequency conversion;

The matching network is used for impedance matching between the input port of the frequency conversion chip in the frequency conversion network and the output port of the antenna;

The resonant network is used for resonant matching of the resonator;

The frequency conversion network includes a frequency conversion chip, a resonator, and a capacitor, the frequency conversion chip is connected to the resonator, the resonator is connected to the capacitor, and the capacitor is grounded;

The antenna network is connected to a matching network, the matching network is connected to a resonant network, and the resonant network is connected to a frequency conversion network.

The driven signal frequency f1 is determined by the resonant frequency f1’ of the resonator in the resonant network and the transmitting driving signal frequency f0 of the transceiver gateway. The calculation formula is: f1= f0 - f1’;

If there are multiple common sensors under the same transceiver gateway, the driven return frequency of the MDFC sensor can be changed by changing the resonant frequency of the resonator in the MDFC sensor.

According to the resonance formula The resonant frequency of the resonator can be changed by changing the capacitance value of the frequency conversion network.

A further technical solution is that the capacitor of the frequency conversion network is connected in parallel with the resonator, and the capacitor and the resonator are grounded.

According to the formula , C1, C2 are the internal load capacitance of the resonator and are fixed values of physical properties, /> is the crystal's own capacitance,/> is the capacitance of the parallel capacitor;

When the resonator is connected in parallel with the capacitor, the total capacitance It will increase as the parallel capacitance increases, that is, the parallel capacitance increases and the overall capacitance increases. When the parallel capacitance increases, the frequency of the resonator will obviously decrease. Therefore, the frequency of the resonator can be adjusted by the parallel capacitance, and then the driven return frequency of the MDFC sensor can be adjusted.

A further technical solution is that the capacitor of the frequency conversion network is connected in series with the resonator, and the capacitor is grounded.

The series capacitor can also change the overall capacitance value, thereby adjusting the driven return frequency of the MDFC sensor.

Another aspect of the present invention provides a variable capacitance microwave direct-driven variable frequency sensor system:

A variable capacitance microwave direct-driven variable frequency sensor system, comprising the variable capacitance microwave direct-driven variable frequency sensor as described above and a transceiver gateway;

There is at least one variable capacitance microwave direct-driven variable frequency sensor, and different variable capacitance microwave direct-driven variable frequency sensors have different driven return frequencies;

The transceiver gateway is used to send out driving signals and receive driven signals generated by different variable capacitance microwave direct-driven variable frequency sensors, and restore the driven signals to measured data.

As long as different MDFC sensors have different driven return frequencies, a single transceiver gateway can identify different MDFC sensors by the different driven return frequencies, that is, a single transceiver gateway can carry multiple MDFC sensors, improving the problem of insufficient monitoring points in the MDFC sensor system.

A further technical solution is that the variable capacitance microwave direct-driven frequency conversion sensor system also includes a common sensor;

The common sensor comprises a matching network, a resonance network and a frequency conversion network, and the matching network, the resonance network and the frequency conversion network are connected.

As long as the driven return frequencies of the MDFC sensors under the same transceiver gateway are different, the signal sent by the MDFC sensor can be distinguished and identified by the transceiver gateway. In this case, the driven return frequency of the MDFC sensor can be adjusted by adjusting the resonant frequency of the resonator or by increasing the capacitance.

A further technical solution is that the variable capacitance microwave direct-drive frequency conversion sensor system further includes a server;

The server is connected to the transceiver gateway, and is used to receive the tested data restored by the transceiver gateway, store and monitor the data, and send information to other terminals.

The present invention also provides a variable capacitance microwave direct-driven variable frequency sensor control method, which is characterized by comprising the following steps:

The corresponding variable capacitance microwave direct-driven frequency conversion sensor is set at the monitoring point;

The transceiver gateway transmits a driving signal to the variable capacitance microwave direct-drive variable frequency sensor at each monitoring point;

After receiving the driving signal, the variable capacitance microwave direct-driven variable frequency sensor converts the measured value into the change of capacitance or inductance, completes the modulation of the variable frequency signal, and outputs the modulated driven signal;

The modulated driven signals of different frequencies are received through the transceiver gateway, and the modulated driven return signals are restored to the measured data.

A further technical solution is that the variable capacitance microwave direct-driven variable frequency sensor control method comprises the following steps:

The transceiver network sends the restored measured data to the server;

The server compares the measured data with the corresponding set threshold, and determines whether the measured data exceeds the corresponding set threshold based on the comparison result;

If it is not exceeded, the server stores the measured data of each point;

When it exceeds the limit, the server sends an alarm message to other terminals.

Compared with the prior art, the present invention has at least the following beneficial effects: the present invention changes the driven return frequency of the variable capacitance microwave direct-driven variable frequency sensor by adding capacitance to the MDFC sensor variable frequency network, thereby solving the problem that the number of resonator models limits the number of variable frequencies of the sensor. And it enables a single transceiver gateway to receive, identify and restore the measured data of the corresponding variable capacitance microwave direct-driven variable frequency sensor, solving the problem in the prior art that too few sampling points are obtained by arranging a single transceiver gateway at the same location, which is not conducive to the monitoring of equipment or environment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a variable capacitance microwave direct-driven frequency conversion sensor;

FIG2 is a schematic diagram of a frequency conversion network structure of a parallel capacitance sensor;

FIG3 is a schematic diagram of a frequency conversion network structure of a series capacitance sensor;

FIG4 is a schematic diagram of an equivalent circuit inside a resonator;

FIG5 is a schematic diagram of the structure and information transmission of Embodiment 2;

FIG6 is a schematic diagram of load capacitance and frequency error;

FIG. 7 is a schematic diagram of the flow chart of the third embodiment.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

Embodiment 1:

A variable capacitance microwave direct-driven frequency conversion sensor, comprising an antenna network, a matching network, a resonance network, and a frequency conversion network;

The antenna network is used to receive the driving signal sent by the transceiver gateway and the driven return signal after the return sensor completes the frequency conversion;

In this embodiment, the antenna network is composed of a 433MHz antenna, which is composed of a copper dipole radiator using a balanced feeding structure, and is used to receive the driving signal sent by the transceiver gateway and send the driven return signal after the sensor modulation is completed;

The matching network is used for impedance matching between the input port of the frequency conversion chip and the output port of the antenna in the frequency conversion network. In this embodiment, the matching network is a 433MHz matching network composed of capacitors and inductors;

The resonant network is used for resonance matching of the resonator. In this embodiment, the resonant network is composed of inductors and capacitors.

The frequency conversion network includes a frequency conversion chip, a resonator, and a capacitor, the frequency conversion chip is connected to the resonator, the resonator is connected to the capacitor, and the capacitor is grounded;

Referring to FIG. 1 , the antenna network is connected to a matching network, the matching network is connected to a resonant network, and the resonant network is connected to a frequency conversion network.

The resonator and the capacitor can be connected in two ways. One way is that the capacitor of the frequency conversion network is connected in parallel with the resonator, and the capacitor and the resonator are grounded, see FIG2 ;

The other is that the capacitor of the frequency conversion network is connected in series with the resonator and the capacitor is grounded, see FIG3 .

The internal equivalent circuit of the resonator is shown in the dotted box in Figure 4, where (1) and (3) are the resonator start-up pins, and (2) is the ground pin (Note: it is left floating when used here). According to the equivalent circuit of the crystal oscillator, when the capacitors are connected in parallel, the capacitor parallel formula is , C1, C2 are the internal load capacitance of the resonator and are fixed values of physical properties, /> is the crystal's own capacitance,/> is the capacitance of the parallel capacitor;

When capacitors are connected in series, according to the series capacitor formula It can be seen that connecting capacitors in series will result in a total capacitance value of/> Getting smaller and smaller.

Embodiment 2:

A variable capacitance microwave direct-driven variable frequency sensor system, comprising a variable capacitance microwave direct-driven variable frequency sensor, a transceiver gateway, and a server;

There is at least one variable capacitance microwave direct-driven variable frequency sensor, and different variable capacitance microwave direct-driven variable frequency sensors have different driven return frequencies;

The transceiver gateway is used to send out driving signals and receive driven signals generated by different variable capacitance microwave direct-driven variable frequency sensors, and restore the driven signals to measured data, see Figure 5. In this application, the transceiver gateway ADC sampling bandwidth is 10kHz;

The transceiver gateway is used to send out driving signals and receive driven signals generated by different variable capacitance microwave direct-driven variable frequency sensors, and restore the driven signals to measured data.

MDFC sensors include voiceprint sensors, temperature sensors, vibration sensors, etc. In this application, the MDFC sensors are temperature sensors, and there are 4 of them, namely 3 parallel capacitance sensors and 1 series capacitance sensor. The driven return frequency difference of each variable capacitance microwave direct-drive frequency conversion sensor is greater than the sampling bandwidth of the transceiver gateway of 10kHz.

In this embodiment, the resonator is a ceramic resonator, and the specific structure of the three parallel capacitive sensors is that a 30/100/500pF capacitor is added between the first and third pins of the ceramic resonator, and the second pin is left floating;

The specific structure of the series capacitance sensor is to add a 30pF capacitor after the ceramic resonator;

After another test, the sensor driving frequency is obtained. The parallel capacitor frequency driving frequency is about 23/100/800kHz lower than the driving frequency before parallel connection, see Figure 6; while the series capacitor frequency driving frequency is about 5kHz lower than the driving frequency before series connection;

It should be noted that, based on the principle of replacing the resonator and the capacitor in parallel, the number of ordinary sensors and capacitive sensors can continue to be increased, and all of them can be accepted, identified and restored by the transceiver gateway.

Embodiment three:

A control method for a variable capacitance microwave direct-driven variable frequency sensor, as shown in FIG7 , comprises the following steps:

S1: Set the corresponding variable capacitance microwave direct-driven frequency conversion sensor at the monitoring point;

S2: The transceiver gateway transmits a driving signal to the variable capacitance microwave direct-drive variable frequency sensor at each monitoring point;

S3: After receiving the driving signal, the variable capacitance microwave direct-driven variable frequency sensor converts the to-be-measured value into a change in capacitance or inductance, completes the modulation of the variable frequency signal, and outputs the modulated driven signal;

S4: Receive the modulated driven signals of different frequencies through the transceiver gateway and restore the driven signals to the measured data.

S5: The transceiver network sends the restored measured data to the server;

S6: The server compares the measured data with the corresponding set threshold, and determines whether the measured data exceeds the corresponding set threshold based on the comparison result;

If it is not exceeded, the server stores the measured data of each point;

When it exceeds the limit, the server sends an alarm message to other terminals.

Although the present invention is described herein with reference to the illustrative embodiments of the present invention, it should be understood that those skilled in the art can design many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in the present application. More specifically, within the scope disclosed in the present application, multiple variations and improvements can be made to the components and/or layout of the subject combination layout. In addition to the variations and improvements made to the components and/or layout, other uses will also be apparent to those skilled in the art.

Claims (6)

1. A variable capacitance microwave direct-driven frequency conversion sensor, characterized in that it includes an antenna network, a matching network, a resonant network, and a frequency conversion network; The antenna network is used to receive the driving signal sent by the transceiver gateway and the driven return signal after the return sensor completes the frequency conversion; The matching network is used for impedance matching between the input port of the frequency conversion chip in the frequency conversion network and the output port of the antenna; The resonant network is used for resonant matching of the resonator; The frequency conversion network includes a frequency conversion chip, a resonator, and a capacitor. The frequency conversion chip is connected to the resonator, the resonator and the capacitor are connected in series or in parallel, and the capacitor is grounded. The resonator and the capacitor are connected in series or in parallel to change the overall capacitance value, thereby changing the resonant frequency, thereby adjusting the driven return frequency of different microwave direct-driven frequency conversion sensors. The antenna network is connected to a matching network, the matching network is connected to a resonant network, and the resonant network is connected to a frequency conversion network. 2. A variable capacitance microwave direct-driven variable frequency sensor system, comprising the variable capacitance microwave direct-driven variable frequency sensor and a transceiver gateway as claimed in claim 1; There is at least one variable capacitance microwave direct-driven variable frequency sensor, and different variable capacitance microwave direct-driven variable frequency sensors have different driven return frequencies; The transceiver gateway is used to send out a driving signal and receive a driven return signal generated by different variable capacitance microwave direct-driven variable frequency sensors, and restore the driven return signal to measured data. 3. A variable capacitance microwave direct-driven frequency conversion sensor system as claimed in claim 2, characterized in that it also includes a common sensor; The common sensor comprises a matching network, a resonance network and a frequency conversion network, and the matching network, the resonance network and the frequency conversion network are connected. 4. A variable capacitance microwave direct-driven frequency conversion sensor system as claimed in claim 2, characterized in that it also includes a server; The server is connected to the transceiver gateway, and is used to receive the tested data restored by the transceiver gateway, store and monitor the data, and send information to other terminals. 5. A control method for a variable capacitance microwave direct-driven variable frequency sensor, characterized in that the variable capacitance microwave direct-driven variable frequency sensor system according to any one of claims 2 to 4 is used, comprising the following steps: The corresponding variable capacitance microwave direct-driven frequency conversion sensor is set at the monitoring point; The transceiver gateway transmits a driving signal to the variable capacitance microwave direct-drive variable frequency sensor at each monitoring point; After receiving the driving signal, the variable capacitance microwave direct-driven variable frequency sensor converts the measured value into the change of capacitance or inductance, completes the modulation of the variable frequency signal, and outputs the modulated driven return signal; The modulated driven return signals of different frequencies are received through the transceiver gateway, and the modulated driven return signals are restored to the measured data. 6. A variable capacitance microwave direct-driven frequency conversion sensor control method as claimed in claim 5, characterized in that it comprises the following steps: The transceiver gateway sends the restored tested data to the server; The server compares the measured data with the corresponding set threshold, and determines whether the measured data exceeds the corresponding set threshold based on the comparison result; If it is not exceeded, the server stores the measured data of each point; When it exceeds the limit, the server sends an alarm message to other terminals.