High-frequency carrier type thin-film sensor using low-noise crystal oscillator

S. Yabukami, H. Mawatari, Y. Murayama, T. Ozawa, K. Ishiyama, K. I. Arai

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


We have developed a very sensitive high-frequency carrier-type magnetic field sensor based on the giant magneto-impedance effect available at lower frequencies. Our approach is to optimize the sensor structure so as to obtain high impedance. In addition, we optimize the carrier suppressing circuit using a low-noise crystal oscillator to reduce the phase noise of the lower offset frequency (under 1 kHz) as a carrier source. When a small ac magnetic field is applied to the sensor element, a very small AM signal can be detected using a carrier suppressing circuit with a low-noise crystal oscillator. A resolution of 1.7 × 10-8 Oe/Hz1/2 was obtained at 501 kHz. The detectable magnetic Held is limited by the thermal noise of room temperature. Resolutions of 1.5 × 10-7 Oe/Hz1/2 at 1 kHz and a resolution of 1.1 × 10-6 Oe/Hz1/2 at 110 Hz were demonstrated. The resolution was basically limited by the phase noise of the crystal oscillator.

Original languageEnglish
Pages (from-to)2670-2672
Number of pages3
JournalIEEE Transactions on Magnetics
Issue number4 II
Publication statusPublished - 2004 Jul


  • Carrier suppression technique
  • Giant magneto impedance
  • High-frequency carrier-type sensor
  • Low frequency
  • Thin film

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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