Two-terminal ultrahigh frequency carrier type thin-film magnetic sensor using impedance matching lines
✍ Scribed by Masakatsu Senda
- Book ID
- 104092684
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 548 KB
- Volume
- 157
- Category
- Article
- ISSN
- 0924-4247
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✦ Synopsis
This article reports on output and band characteristics of the two-terminal ultrahigh frequency (UHF) carrier type magnetic field sensor, which is based on impedance change due to magnetic field dependent permeability, and a magnetic field is detected as an amplitude modulation of a UHF carrier voltage. Two types of transmission line configurations (type-A and type-B) are proposed to make a two-terminal sensor rather than the four terminals of the conventional sensor operating on this principle, because the twoterminal sensor is more advantageous in terms of designing and fabricating of the sensor element and the transmission lines than the four-terminal sensor. In the type-A, a half-wave impedance matching line is added between the element and the carrier power supplying points. Also, in the type-B, a carrier power is supplied on the quarter-wave matching line located between the element and the load. The type-A sensor exhibits a lower output and a much narrower 3 dB-bandwidth of a few tens of MHz than the fourterminal sensor. In contrast, a higher output than that in the four-terminal sensor and a 3 dB-bandwidth of ∼100 MHz are confirmed in the type-B sensor by experiments and calculations.