DIELECTRIC PROPERTIES OF (Sr_0.8Pb_0.2)TiO₃-MgO COMPOSITES AT LOW AND MICROWAVE FREQUENCIES

ABSTRACT

(Sr_0.8Pb_0.2)TiO₃-MgO (50:50 by weight) composites are fabricated and their dielectric properties are investigated at room temperature in the frequency range between 10 kHz and 26 GHz. Relative dielectric constant is ∼116. tan δ at 10 kHz is 0.0005 or less than 0.0005, but tan δ at higher frequencies increases to 0.006 at 4 GHz and 0.04 between 18 GHz and 26 GHz. The resonant methods show constant Q × f (Q: 1/tan δ, f: Frequency) ∼700 GHz in the frequency range of 2.5 GHz to 7 GHz, but the waveguide technique shows different values because of low accuracy in measuring tan δ.

ACKNOWLEDGMENTS

Partial financial supports were provided by DARPA under contract No. DABT 63-98-1-002. One of the authors (Y. S.) would like to express gratitude to Dr. K. Z. Rajab for the help of high frequency property measurements and Ms. D. A. Baumgardner for her help.

Notes

∗S11 was measured at 23°C, but the others were measured at 25°C.

∗S5-a, b. c were measured at 23°C, but the others were measured at 25°C.