Self-calibration circuits and routines for low-cost measuring systems

✍ Scribed by Thorsten Sokoll; Arne F. Jacob

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 599 KB
• Volume: 50
• Category: Article
• ISSN: 0895-2477
• DOI: 10.1002/mop.23083

✦ Synopsis

Abstract

A Low‐cost measurement system suited for in situ moisture monitoring of buildings is presented. The system consists of a robust and compact resonant microwave sensor linked to a miniaturized, low‐cost vector network analyzer. Several such systems can be controlled by a central monitoring station. The measurement accuracy is enhanced significantly by vectorial self‐calibration. To determine the magnitude and the required 360°‐phase information, an inexpensive combined gain and 180°‐phase detector is used, where the full phase information is obtained by adequately modeling the sensor's and the calibration standards' phase response. Different self‐calibration circuits are examined and their suitability is proved by comparative measurements. Finally, the system's performance is tested in a high humidity environment. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 287–293, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23083