Flexible-substrate-based passive wireless pressure sensor with self-packaging function

Abstract

The invention discloses a flexible-substrate-based passive wireless pressure sensor with a self-packaging function. The pressure sensor comprises an upper flexible substrate, an upper metal layer, a middle flexible substrate, a lower metal layer and a lower flexible substrate, which are sequentially arranged from top to bottom and fixedly connected. An electric through hole and a cavity are formed in the middle flexible substrate. The upper metal layer comprises a planar inductance coil and a capacitor upper polar plate positioned on the middle part of the planar inductance coil. An inner connector of the planar inductance coil is connected with the capacitor upper polar plate. The lower metal layer comprises a capacitor lower polar plate opposite to the upper plate capacitor and an interconnecting wire connected with the capacitor upper polar plate. The sizes of the capacitor upper polar plate and capacitor lower polar plate are the same. An outer connector of the planar inductance coil of the upper metal layer is connected with the interconnecting wire of the lower metal layer through a conductive medium column in the electric through hole. The cavity of the middle flexible substrate is positioned between the capacitor upper polar plate and capacitor lower polar plate. The pressure sensor has the high performance of self packaging, non-contact, high sensitivity and high quality factor.

Description

technical field [0001] The invention belongs to the technical field of sensors, and in particular relates to a passive wireless pressure sensor based on a flexible substrate and having a self-packaging function. Background technique [0002] Pressure sensors are widely used in many occasions. In some special applications, such as: inside the human body, food packaging and other sealed environments, pressure sensors are required to have wireless telemetry capabilities. There are currently two types of wireless telemetry pressure sensors: active telemetry and passive telemetry. Active telemetry means that the sensing system has a power source. This type of telemetry can transmit sensor signals in both directions over long distances, but the system is complex, large in size, and the battery needs to be replaced. Passive telemetry means that there is no power source in the sensing system, and signals are acquired by using inductive coupling or radio frequency (RF) reflection mo...

AI Technical Summary

Problems solved by technology

The inductance can be an on-chip inductance integrated with a capacitive sensor, but it is generally difficult to obtain a high quality factor Q for this inductance, thereby limiting the overall characteristics of the device; in addition, an externally wound metal wire inductance coil can also be used. But this will increase the size of the device, and it is difficult to process in batches

In addition, MEMS pressure-sensitive capacitors also need to solve two major technical difficulties: the lead wire of the capacitor plate and the sealing of the cavity

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