This paper presents a design of proximity vital sign sensor using a self-oscillating mixer (SOM) at 2.45 GHz. The proposed system consists of a planar resonator that determines the oscillation frequency and a transistor that functions not only as an oscillator but also as a mixer. Note that the supply voltage of the transistor is in pinch-off region to maximize non-linearity. The input impedance of the resonator is varied due to the distance variation between the human body and the resonator. This variation of input impedance changes the oscillation frequency of the proposed sensor. Then, this frequency deviation is self-mixed in the transistor. It can be detected at the emitter in a form of DC voltage, because the proposed system is a kind of direct conversion receiver. So, if we track the emitter voltage, we can obtain the vital sign of the human subject. The measurement results confirm that the proposed sensor can detect the vital sign at 20 mm away from a subject.
|Title of host publication||2016 URSI Asia-Pacific Radio Science Conference, URSI AP-RASC 2016|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|Number of pages||3|
|Publication status||Published - 2016 Oct 19|
|Event||2016 URSI Asia-Pacific Radio Science Conference, URSI AP-RASC 2016 - Seoul, Korea, Republic of|
Duration: 2016 Aug 21 → 2016 Aug 25
|Name||2016 URSI Asia-Pacific Radio Science Conference, URSI AP-RASC 2016|
|Other||2016 URSI Asia-Pacific Radio Science Conference, URSI AP-RASC 2016|
|Country||Korea, Republic of|
|Period||16/8/21 → 16/8/25|
Bibliographical notePublisher Copyright:
© 2016 IEEE.
All Science Journal Classification (ASJC) codes
- Signal Processing
- Computer Networks and Communications