A modified polyimide and its application to a microwave relative humidity sensor

Author

Kim, Yong-Ho ; Lee, Joon-Ik ; Shin, Kyu-Ho ; Kim, Yong-Jun

Author_Institution

Dept. of Mech. Eng., Yonsei Univ., Seoul, South Korea

Volume

2

fYear

2005

fDate

5-9 June 2005

Firstpage

1848

Abstract

This paper reports a modified polyimide and its application to a microwave relative humidity (RH) sensor. For a highly sensitive moisture sensing layer, a polyimide was synthesized from oxidianiline (ODA), m-pyromellitic dianhydride (m-PMDA) and N-methylpyrrolidone (NMP) instead of using a commercial polyimide. The synthesized polyimide was applied to a microwave humidity sensor, CPW-to-slotline ring resonator in this case. Characteristics of the fabricated microwave humidity sensor including sensitivity, hysteresis and stability were analyzed for various relative humidity levels. Sensitivity of the RH sensor, in terms of resonant frequency change, was 181 kHz/%RH, hysteresis was 0.013%, and deviation from an average resonant frequency was 0.002% at 40%RH.

Keywords

humidity measurement; humidity sensors; microwave measurement; polymers; CPW-to-slotline ring resonator; N-methylpyrrolidone; RH sensor; hysteresis; m-pyromellitic dianhydride; microwave relative humidity sensor; moisture sensing layer; oxidianiline; polyimide; relative humidity levels; resonant frequency; sensitivity; stability; Acoustic sensors; Dielectric constant; Humidity; Mechanical sensors; Microwave sensors; Moisture; Polyimides; Radio frequency; Resonant frequency; Sensor phenomena and characterization;

fLanguage

English

Publisher

ieee

Conference_Titel

Solid-State Sensors, Actuators and Microsystems, 2005. Digest of Technical Papers. TRANSDUCERS '05. The 13th International Conference on

Print_ISBN

0-7803-8994-8

Type

conf

DOI

10.1109/SENSOR.2005.1497455

Filename

1497455