## 1 Introduction  
Large amounts of gas are generated during the coal-mining process. Its main component is methane (about 83-89%), which is flammable and explosive, and its explosion range is 5-16% [1; 2; 3] of the volume fraction. Therefore, it is particularly important to achieve accurate monitoring of underground methane. In recent years, with rapid industrialization, many methane sensors have emerged, which can be divided into infrared spectral, semiconductor, ultrasonic, and catalytic combustion according to the different detection principles. Compared with other types of sensors, the catalytic combustion type exhibits high sensitivity, fast response time, stable performance, and low-power consumption, has a simple production process, and has an inexpensive nature. At present, catalytic combustion technology is widely used in coal-mine-networking methane sensors and is the most economical and effective among other options [4], making it suitable for the development needs of the Internet of Things in the construction of smart mines. Therefore, it is necessary to perform a system simulation of catalytic combustion methane sensors to improve their local performance. The sensor structure can also be improved, and external factors can be adjusted to enhance their overall performance. Based on the different structures of catalytic combustion methane sensors, it is mainly divided into two structures: traditional pellet-shaped and silicon-based planar array plates. The sensor carrier is prepared, and the catalyst is loaded by impregnating the same volume of catalyst and promoter into Al\({}_{2}\)O\({}_{3}\) powder [5]. Although it has the advantages of a large specific surface area and simple process [6], its \"blind hole\" makes methane burn on the surface of the sensor, while the limited diffusion of reactants affects the activity of the catalyst and even deactivates, resulting in the decrease of the sensor's stability, performance, and detection accuracy [7; 8]. [PERSON] et al. [9] prepared palladium and multiwalled carbon nanotube (MWNT) composites using the simple method of reducing NaBH aqueous mixture, thereby improving the detection ability of the sensor for methane at room temperature. [PERSON] [10] deposited carbon nanotubes (CNTs) by electrodeposition technology to reduce their hole concentration and increase the resistivity of the manufactured CH\({}_{4}\) sensor. [PERSON] et al. [11] developed lithium-ion-doped CNTs as sensing elements to detect and estimate methane, resulting in sensors with a maximum sensitivity at 14 ppm of \(\sim\)5.500%. [PERSON] et al. [12] used MWNTs combined with carrier modification technology to produce a fast-response thermal conductivity gas sensor, thereby improving the response speed of the methane sensor. [PERSON] [13] modified single-walled CNTs with transition metals (Fe, Ni, and Pd), enhanced the adsorption capacity of methane, and improved the sensitivity and selectivity of the sensor. Additionally, microheating plates have also been developed. For example, [PERSON] et al. [14] developed a microheating plate catalytic methane sensor based on porous anodic alumina and achieved a sensor response value of \(\sim\)15 mV/vol. [PERSON] et al. [15] found that using insulating thermal conductive film can greatly improve the temperature under the same voltage by comparing three types of microheating plates with different structures. [PERSON] [16] and [PERSON] et al. [17] arranged the heating resistor and interdigital electrode on the front and back of the LTCC ceramic plate and found that the sensor has good thermal stability. [PERSON] et al. [18] used a silicon-based microelectromechanical system (MEMS) to conduct microheating plate processing and electrical connection according to the parameters optimized using the finite element method. They also designed a microheating plate with low-power consumption. The abovementioned studies improved the sensitivity and detection accuracy of methane sensors at varying degrees.