A Parasitic Insensitive Catheter-Based Capacitive Force Sensor for Cardiovascular Diagnosis

Sangkuk Jeon, Jiyong Lee, Hyunseok Hwang, Wonhyoung Ryu, Youngcheol Chae

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12 Citations (Scopus)


This paper presents a catheter-based capacitive force sensor interface for cardiovascular diagnosis. The force sensor is implemented on a flexible printed circuit board (FPCB) substrate with a force-sensitive polydimethylsiloxane (PDMS), and a force-induced change in a capacitance of the sensor is measured by a precision capacitive sensor interface. To recover the performance degradation caused by the large parasitic capacitance C P of a long catheter, we present a parasitic insensitive analog front-end (AFE) with active C P cancellation, which employs a charge amplifier and a negative capacitor at the virtual ground of the charge amplifier. The prototype sensor was measured with a force loader in whole blood. The proposed AFE successfully cancels C P of 348 pF in a 0.9-m-long sensor and measurement results show the SNR of 53.8 dB and the capacitance resolution of 16 aF, a 19.6 dB improvement by canceling nonideal effect of C P. This corresponds to a force resolution of 2.22 gf, which is 9.29 × reduction compared to the work without the C Pcancellation. The proposed sensor interface is insensitive to C P from hundreds to 1-nF level, and the force-dependent stiffness of two different tissues has been successfully distinguished with an ex-vivo experiment. The proposed sensor interface enables the integration of capacitive force sensors in a smart catheter.

Original languageEnglish
Article number8386817
Pages (from-to)812-823
Number of pages12
JournalIEEE Transactions on Biomedical Circuits and Systems
Issue number4
Publication statusPublished - 2018 Aug

Bibliographical note

Funding Information:
Manuscript received December 17, 2017; revised February 24, 2018 and April 10, 2018; accepted April 12, 2018. Date of publication June 15, 2018; date of current version August 15, 2018. This work was supported by the National Research Foundation of Korea (NRF) Grant funded by Mid-Career Researcher Program through NRF Grant funded by the MEST (2016R1A2B4010487). This paper was recommended by S.-Y. Lee. (Corresponding authors: WonHyoung Ryu and Youngcheol Chae.) S. Jeon is with the Department of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749, South Korea, and also with LG Electronics, Seoul 07796, South Korea (e-mail:,sk.jeon@yonsei.ac.kr).

Publisher Copyright:
© 2007-2012 IEEE.

All Science Journal Classification (ASJC) codes

  • Biomedical Engineering
  • Electrical and Electronic Engineering


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