MEMS microwave power sensor capable of realizing online self-detection and preparation method thereof

Abstract

The invention discloses an MEMS microwave power sensor capable of realizing online self-detection, which is characterized in that a capacitive MEMS microwave power sensor and a symmetric thermoelectric MEMS microwave power sensor are connected in series to the two sides of an MIM capacitor to form a dual-channel MEMS microwave power sensor; and the resistance value of a load resistor can be detected by applying a reference voltage to a pressure welding block connected with a standard resistor by using a voltage division method. If the detected resistor is in a normal working state, the load resistors on the two sides of a thermopile can obtain the same voltage and convert the voltage into the same heat, that is, the temperature difference between the two sides of the thermopile is completely generated by the input microwave power. The MIM capacitor is arranged on a coplanar waveguide signal line on the left side, so that direct-current interconnection of a coplanar waveguide signal line below an MEMS cantilever beam and a coplanar waveguide signal line behind the MEMS cantilever beam is isolated, and the function of detecting the load resistance while measuring the microwave poweris achieved. The MEMS microwave power sensor has the characteristics of low loss, high sensitivity and online self-detection of terminal resistance.

Description

technical field [0001] The invention provides a MEMS microwave power sensor capable of online self-detection and a preparation method thereof, belonging to the technical field of micro-electromechanical systems (MEMS). Background technique [0002] In microwave technology research, microwave power is an important parameter to characterize microwave signals. In the research of each link of microwave signal generation, transmission and reception, the measurement of microwave power is essential. Microwave power sensors are usually used to measure microwave power. At present, typical MEMS microwave power sensors mainly include two types: capacitive MEMS microwave power sensors and pyroelectric MEMS microwave power sensors. The capacitive MEMS microwave power sensor is based on the principle of microwave power-force-electricity conversion. It characterizes the magnitude of microwave power by measuring capacitance, and is usually suitable for the measurement of relatively large...

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Problems solved by technology

[0003] Technical problem: In order to overcome the deficiencies in the prior art, the present invention proposes a MEMS microwave power sensor capable of online self-detection and its preparation method. The MEMS microwave power sensor adopts a completely passive structure; Two metal connecting wires are drawn from the coplanar waveguide (CPW) signal line on the left side of the MEMS microwave power sensor. One of the metal connecting wires is connected in series with a standard resistor and connected to one of the external pressure blocks, and the other is connected to the external pressure block through the metal connecting wire. The external pressure block 2 is directly connected; the CPW signal line on the right side of the symmetrical thermoelectric MEMS microwave power sensor is connected in series with another standard resistor through a metal connection line and connected with the external pressure block 1, thus forming an online automatic load resistance circuit. Symmetrical pyroelectric MEMS microwave power sensor with detection function; apply a DC reference voltage to the external pressure block 1, and use the voltage division method to measure the divided voltage of the load resistance through the external pressure block 2, and then the resistance value of the load resistance can be detected. At the same time, the CPW signal line on the other side of the symmetrical thermoelectric MEMS microwave power sensor will share the same voltage, causing the load resistance on both sides of the thermopile to consume the same DC power and generate the same heat, that is, the DC reference The voltage causes the temperature change on both sides of the thermopile to be the same, so the temperature difference on both sides of the thermopile is still caused by the microwave power to be measured, and is not affected by the DC reference voltage, thus realizing online self-detection when measuring microwave power The function of the load resistance; a capacitive MEMS microwave power sensor is placed on the left side of the symmetrical thermoelectric MEMS microwave power sensor, where the MEMS cantilever spans the CPW signal line and the ground wire on the lower side of the signal line, and the anchor area of ​​the MEMS cantilever beam Fix the outer side of the ground wire on the lower side of the signal line, place a sensing electrode near the CPW signal line under the MEMS cantilever beam, and cover the sensing electrode, CPW signal line and ground wire under the MEMS cantilever beam with a layer of Si 3 N 4 Insulating dielectric layer; when the microwave signal is transmitted to the capacitive MEMS microwave power sensor, due to the electrostatic effect, an electrostatic force is generated between the MEMS cantilever beam and the CPW signal line, which reduces the height of the MEMS cantilever beam, thereby changing the MEMS cantilever beam and the CPW signal line. The capacitance value between the sensing electrodes, so that by measuring the change of the capacitance, the microwave power to be measured can be indirectly measured; two kinds of MEMS microwave power sensors, capacitive and pyroelectric, pass through a metal-insulating layer on the CPW signal line -Metal (MIM) capacitors are connected, and MIM capacitors can transmit microwave signals, but block the DC connection on the CPW signal line of the capacitive and pyroelectric MEMS microwave power sensors, thus ensuring that the capacitive MEMS microwave power sensors The amount of capacitance change is completely caused by the microwave power to be measured; therefore, the MEMS microwave power sensor proposed by the present invention has the characteristics of online self-detection of load resistance, large power measurement range and high sensitivity

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