Temperature compensation method and device for thermistor power sensor

Abstract

The invention discloses a temperature compensation method and device for a thermistor power sensor, and the method comprises the steps: arranging a plurality of temperature sensing elements in the power sensor, and collecting the temperature data of the inner side of a power sensor housing, the inner side of a power flange seat, and the temperature data above a thermosensitive element protection barrel in real time; acquiring a compensation value of power drift caused by the environment temperature through the reference end of the power sensor; based on the temperature data of the plurality of temperature sensing elements and the reference end compensation value, the output power after temperature compensation is calculated by using the compensation model, a plurality of key positions are collected in real time, the output power after reference end compensation is compensated again by using the temperature value, the power error generated by the working end along with the temperature change is eliminated, and the accuracy of the power compensation is improved. The method can effectively counteract output power errors caused by insufficient technological level, and the stability of power measurement is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave remote sensing geological disaster monitoring, and in particular to a temperature compensation method and device for a thermistor power sensor. Background Art

[0002] The widespread application of RF and microwave technologies in fields such as communications, radar, and electronic testing has placed higher demands on the accuracy and stability of power measurements. As core measurement components, power sensors must possess high sensitivity and excellent temperature stability. Thermal power sensors, due to their high measurement accuracy, excellent linearity, and high-frequency adaptability, have become the preferred choice in many applications.

[0003] A thermistor-type power sensor primarily consists of a waveguide base, a thermistor, and a sensing chip. During operation, an RF signal is introduced through the waveguide port, causing the sensing chip to heat up. This heat is then transferred to the thermistor, causing its resistance to change. To measure RF power, a DC bias voltage is applied to the thermistor before the RF input. After the temperature stabilizes, an RF signal is applied to further heat the thermistor. The power meter automatically adjusts the bias voltage to maintain a constant thermistor resistance. The change in bias voltage is then used to calculate the RF power.

[0004] Traditional methods use a reference terminal, symmetrically positioned with the working terminal, to compensate for power drift caused by temperature fluctuations at the working terminal using its output. However, due to limited laboratory process capabilities, perfect symmetry is difficult to achieve during sensor manufacturing, and residual errors often exist in the compensation of the working terminal by the reference terminal.

[0005] In the prior art, in order to compensate for the influence of ambient temperature changes on the thermal-sensitive power socket type power sensor during operation, a temperature compensation solution with a double-ended symmetrical structure is usually adopted.

[0006] This solution builds on the structure of a traditional two-terminal thermistor power sensor. It integrates a temperature acquisition system within the power sensor. This system, comprising multiple temperature sensing elements, collects temperature data from the inner wall of the sensor housing, the inside of the power flange, and above the thermistor protection barrel. This system monitors temperature changes within the sensor in real time and performs secondary compensation on the output power of a traditional two-terminal sensor, accurately correcting errors caused by temperature fluctuations. Summary of the Invention

[0007] The purpose of the present invention is to provide a temperature compensation method and device for a thermistor power sensor, aiming to solve the problem that the traditional reference end compensation method cannot effectively eliminate the temperature error under the condition of low process level.

[0008] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0009] In one aspect, the present invention comprises the steps of:

[0010] Multiple temperature sensing elements are set inside the power sensor to collect real-time temperature data of the inner wall of the sensor housing, the inner side of the power flange seat and the top of the thermistor protection barrel;

[0011] Obtaining a compensation value for power drift caused by ambient temperature through the reference terminal of the power meter of the power sensor;

[0012] Based on the temperature data of the plurality of temperature sensing elements and the reference end compensation value, the output power after temperature compensation is calculated using a compensation model,

[0013] The compensation calculation model is shown in the formula:

[0014]

[0015] Among them, P out is the power output after temperature compensation; P work is the working end power value; P re is the reference end power value; t i Indicates the local temperature value collected by the temperature sensor; B i is the corresponding temperature compensation coefficient; A1 is the power correction factor.

[0016] Furthermore, the temperature sensing element is a thermocouple or other thermal sensitive element, which is arranged on the inner wall of the sensor, the inner side of the power flange seat or the upper side of the protective barrel.

[0017] Furthermore, the power sensor performs calculation of the compensation model through a signal processing platform, and the signal processing platform is used to receive power data and temperature acquisition data from the reference end and working end of the power meter.

[0018] On the other hand, a temperature compensation device for a thermistor power sensor includes a sensor body, a temperature acquisition system and a signal processing platform. A power meter is provided outside the sensor, and the power meter is provided with a working end and a reference end output. The temperature acquisition system also includes multiple temperature sensing elements for collecting the temperature of the inner wall of the sensor housing, the inner side of the power flange seat and the top of the thermistor protection barrel; the signal output end of the temperature acquisition system and the signal output end of the sensor body are respectively connected to the signal input end of the signal processing platform, and the signal processing platform is used to calculate the output power after temperature compensation.

[0019] Furthermore, the outer cover of the temperature sensing element is provided with a sealing barrel to reduce external temperature field interference.

[0020] Furthermore, the reference end and the working end of the sensor body are structurally symmetrical, and the reference end does not receive radio frequency signals.

[0021] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0022] 1. The present invention collects temperature data at multiple key locations in real time and uses this temperature value to compensate the output power after reference end compensation, eliminating the power error caused by temperature changes in the compensated power output. This method can effectively offset the output power error caused by insufficient process level and significantly improve the stability of power measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is an overall block diagram of a thermistor power sensor according to a temperature compensation method of the thermistor power sensor of the present invention;

[0024] Figure 2 A schematic diagram of a thermistor power sensor according to a temperature compensation method of the thermistor power sensor of the present invention;

[0025] Figure 3 A schematic diagram of a thermistor power sensor waveguide port according to a temperature compensation method for a thermistor power sensor of the present invention;

[0026] Figure 4 A schematic side view of a thermistor power sensor c according to a temperature compensation method of the thermistor power sensor of the present invention;

[0027] Figure 5 A schematic diagram of a thermistor power seat of a thermistor power sensor according to a temperature compensation method of the thermistor power sensor of the present invention;

[0028] Figure 6 Schematic diagram of the comparison between WR5* and PM5 no-power of a temperature compensation method for a thermistor power sensor of the present invention;

[0029] Figure 7 This is a graph comparing the PM5 / WR5* power ratio and the PM5 / WR5 power ratio of a temperature compensation method for a thermistor power sensor of the present invention. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] Reference Figure 1 As shown, the present invention provides a temperature compensation method for a thermistor power sensor, comprising: arranging multiple temperature sensing elements inside the power sensor to collect temperature data near the sensing chip, around the thermistor elements, and inside the waveguide structure in real time;

[0032] Obtain the power drift compensation value caused by the ambient temperature through the reference terminal of the power meter of the power sensor;

[0033] Based on the temperature data of the plurality of temperature sensing elements and the reference end compensation value, the output power after temperature compensation is calculated using a compensation model,

[0034] The present invention is based on the traditional double-terminal thermistor power seat type power sensor structure, and integrates a temperature acquisition system inside it, such as Figure 2 The sensor mainly includes a waveguide seat, a sensing chip, a thermal element, and a temperature acquisition component.

[0035] like Figure 3 As shown, the radio frequency signal is incident from the waveguide port (5) and enters the Figure 4 The waveguide cavity (8) shown is in contact with the sensing chip (6). The sensing chip heats up due to receiving radio frequency power, and the temperature of the thermistor (7) attached to the sensing chip rises accordingly and the resistance value changes.

[0036] To measure RF power, a bias voltage must be applied to the thermistor before the RF signal is input. The RF signal is then input after the temperature stabilizes. During this time, the thermistor heats up further, causing its resistance to change. The power meter automatically adjusts the DC bias voltage to maintain a constant operating resistance, allowing the RF power to be calculated based on the change in bias voltage.

[0037] The temperature acquisition system integrated inside the sensor obtains the temperature of key locations such as the inner wall of the sensor housing and the inside of the power flange seat in real time. These data are combined with the reference power value and the compensated power output is recalculated through the algorithm.

[0038] To suppress measurement errors caused by ambient temperature fluctuations, traditional thermistor-type power sensors are usually equipped with a symmetrical reference end (10), which is identical in structure to the working end (9) but does not receive radio frequency signals. This reference end is used to sense the ambient temperature and compensate for the temperature error in the output power of the working end. However, due to the limited laboratory process level, it is difficult to achieve complete symmetry between the reference end and the working end during sensor manufacturing, resulting in residual errors in the compensation effect, and limiting the measurement stability and accuracy.

[0039] To this end, the present invention proposes an enhanced temperature compensation structure based on the above structure, wherein a plurality of temperature sensing elements (3) are integrated inside the sensor to form a temperature acquisition system (1) for real-time acquisition of temperature information at key locations such as the inner wall of the sensor housing, the inner side of the power flange seat, and the upper portion of the thermal element protection barrel; in addition, a sealed small barrel (2) fixed by screws is provided outside the thermal element to reduce the influence of room temperature fluctuations on the internal temperature field of the sensor, thereby improving the consistency of compensation between the reference end and the working end.

[0040] The compensation system of the present invention also includes a signal processing platform (ZYNQ) matched with the sensor, which is used to receive the bias voltage signal output by the thermistor, the power data of the reference end and the working end, and the multi-point temperature information provided by the temperature acquisition system.

[0041] The compensation calculation model is shown in the formula:

[0042]

[0043] Among them, P out is the power output after temperature compensation; P work is the working end power value; P re is the reference end power value; t i Represents the local temperature coefficient collected by the temperature sensor; B i is the corresponding temperature compensation coefficient; A1 is the power correction factor; e is a constant.

[0044] In this embodiment, Figures 2 to 5 As shown, the sensor comprises: a waveguide seat (4), a temperature detection element (3), a waveguide port (5), a waveguide cavity (8), a sensing chip (6), a thermal element (7), a working end (9), a reference end (10), a sealed barrel (2) and a temperature acquisition system (1).

[0045] The sensing chip is made of a silicon (Si) substrate and has good thermal conductivity, and is used to absorb radio frequency power and generate heat; the sensing chip is pasted on the waveguide with thermal conductive gel (kafuter K-5204K), and the thermistor (thin film platinum resistor PT1000, room temperature resistor 1000 ohm) is pasted on the sensing chip with thermal conductive gel; the temperature acquisition system (1) is used to collect and amplify the voltage of the temperature detection element, and includes 6 temperature detection elements (thermocouple model: Kapson thermocouple K type), which are respectively arranged on the inner wall of the sensor, the inner side of the power flange seat, and the upper side of the protective barrel; the output voltage of the thermocouple will change with the change of temperature, and the resistance value of the thin film platinum resistor PT1000 will change with the change of temperature.

[0046] Working process:

[0047] The tests were conducted in the terahertz frequency band using a power sensor in the WR5 band. Therefore, the device described in this invention is referred to as the WR5. To verify the effectiveness of the temperature compensation structure described in this invention, a PM5 power sensor (model omitted) was introduced as a comparison standard. The output stability of the PM5 and WR5 was analyzed under both zero-power input and actual input conditions.

[0048] The test process is as follows:

[0049] First, an external power meter applies a bias voltage (3V) to the thermistor to drive it into a thermally stable state;

[0050] The sensing chip (6) is not subject to external radio frequency excitation at this time, but is only affected by the ambient temperature;

[0051] The temperature acquisition system (1) collects the tiny voltage difference caused by internal temperature changes and processes it through the ZYNQ signal processing platform;

[0052] Synchronously record the bias voltage values ​​of the thermistor at the working end and the reference end, respectively:

[0053] V work is the bias voltage of the working end thermistor (PT1000);

[0054] V pre is the bias voltage of the reference end thermistor (PT1000);

[0055] P1 is the output power value after reference end temperature compensation;

[0056] 1120Ω is the working resistance of the thermistor;

[0057] e is a constant;

[0058] A1 is the power correction factor;

[0059] The calculation model of the signal processing platform is as follows:

[0060]

[0061] The voltage (v1-v6) output by the temperature detection element is normalized to obtain the temperature coefficient (t1-t6), where aver i is the average voltage value, st i is the standard deviation voltage value:

[0062]

[0063] Then compensate P out is the final power output, P1 is the power output after reference end compensation, t iRepresents the local temperature coefficient collected by the temperature sensor; B i The corresponding temperature compensation coefficient is:

[0064] After 2.5 hours of continuous input without RF signal, Figure 5 The data shows:

[0065] When WR5 is not compensated, the output power fluctuation range is ±3.5μW;

[0066] After being processed by the temperature compensation structure of the present invention, the output fluctuation dropped by 83%, and the fluctuation amplitude was less than ±0.6μW; this was highly consistent with the output result of PM5, verifying that the present structure has a good compensation effect.

[0067] In the second phase of the experiment, a signal source (Hewlett-Packard HP 83752A) with an output power of 14GHz and 1.9dBm was used. A terahertz band spreader module (TLSE-140220-0530-05, with an output frequency range of 140GHz to 220GHz) was used to transmit the signal simultaneously to WR5 in the sidearm and PM5 in the main arm via a directional coupler. The test lasted 2.5 hours.

[0068] like Figure 6 Figure 2 shows the PM5 / WR5* and PM5 / WR5 power ratio curves during RF power testing. Using PM5 output power as a reference, the PM5 to WR5* and WR5 ratios were constructed. The results demonstrate that using the temperature sensing element described in this invention for compensation significantly stabilizes WR5 power output and reduces measurement fluctuations.

[0069] In summary, the enhanced temperature compensation structure proposed in this embodiment demonstrates excellent resistance to temperature drift and power measurement stability under actual process conditions. Compared with the existing reference device PM5, it exhibits lower output fluctuations under both zero-power and high-power conditions. Compared with single-reference-end compensation under power conditions, it also has a more stable output, verifying the effectiveness and application value of the structure of the present invention.

[0070] The above content is merely an example and explanation of the structure of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A temperature compensation method for a thermistor power sensor, characterized in that: The following steps are involved: Multiple temperature sensing elements are set inside the power sensor to collect real-time temperature data of the inside of the power sensor housing, the inside of the power flange seat and the top of the thermal element protection barrel; Obtain the compensation value of power drift caused by ambient temperature through the reference end of the power sensor; Based on the temperature data of the plurality of temperature sensing elements and the reference end compensation value, the output power after temperature compensation is calculated using a compensation model, The compensation calculation model is shown in the formula: Among them, P out is the power output after temperature compensation; P work P is the power value measured at the working end; re is the reference power value; T i Indicates the local temperature value collected by the temperature sensor; B i is the corresponding temperature compensation coefficient; A1 is the reference end power correction factor.

2. The temperature compensation method of a thermistor power sensor according to claim 1, characterized in that: The temperature sensing element is a thermocouple or other thermistor, which is arranged on the inner wall of the sensor housing, the inner side of the power flange seat and the upper side of the thermistor protection barrel.

3. The temperature compensation method of a thermistor power sensor according to claim 1, characterized in that: The power sensor performs calculation of the compensation model through a signal processing platform, and the signal processing platform is used to receive power data and temperature acquisition data from the reference end and the working end of the power meter.

4. A temperature compensation device for a thermistor power sensor, for executing the method according to any one of claims 1 to 3, comprising a sensor, a power meter provided outside the sensor, the power meter having a working end and a reference end output, characterized in that: It also includes a temperature acquisition system and a signal processing platform. The temperature acquisition system includes multiple temperature sensing elements for collecting the temperatures of the inner wall of the sensor housing, the inner side of the power flange seat and the thermistor protection barrel; the signal output end of the temperature acquisition system and the signal output end of the power meter are respectively connected to the signal input end of the signal processing platform, and the signal processing platform is used to calculate the output power after temperature compensation.

5. The temperature compensation device of the thermistor power sensor according to claim 4, characterized in that: The outer cover of the temperature sensing element is provided with a sealing barrel for reducing external temperature field interference.

6. The temperature compensation device of the thermistor power sensor according to claim 4, characterized in that: The reference end and the working end of the sensor body are structurally symmetrical, and the reference end does not receive radio frequency signals.

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