A passive wireless pressure sensor based on flexible substrate

Abstract

The invention discloses a passive wireless pressure sensor based on a flexible substrate, which comprises an upper metal layer, an upper flexible substrate, a middle flexible substrate, a lower flexible substrate and a lower metal layer. There are connected electrical through holes, and a cavity is provided on the middle flexible substrate; the upper metal layer includes a planar inductance coil and a capacitor upper plate located in the middle of the planar inductance coil, and the inner connector of the planar inductance coil is connected to the capacitor upper plate; The lower metal layer includes a capacitor lower plate that is the same size as the capacitor upper plate and is opposite to the capacitor, and an interconnection line connected to the capacitor lower plate; The conductive medium column is connected with the interconnection line of the lower metal layer, and the cavity of the middle flexible substrate is located between the upper pole plate of the capacitor and the lower pole plate of the capacitor. The pressure sensor has excellent performances of non-contact, high sensitivity, high quality factor and low power consumption.

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. 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 modulation. This telemetry method has a...

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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