volume | PIER Journals

Abstract

A new method for the theoretical analysis of the third-order intermodulation distortion (IM3) in barium strontium titanate (BST) thin film interdigital capacitors (IDCs) on r-plane sapphire substrates is presented. Two circuit topologies-the dual and series dual BST varactor circuit-are proposed and their theoretical models along with simulated and measured results are presented. Low IM₃ is demonstrated and experimentally verified. By proper selective biasing, very low nulls are observed in both dual and series dual BST varactor circuit topologies which indicate minimum distortion. The measured first nulls are achieved at ±13 V and ± 20 V for the dual and series dual topologies respectively. These results demonstrate the potential of incorporating these highly linear BST varactors in silicon on sapphire (SoS) applications.

1. Gevorgian, S., "Introduction: Overview of agile microwave technologies," Ferroelectrics in Microwave Devices, Circuits and Systems: Physics, Modelling, Fabrication and Measurements, 1st Edition, 1-19, Springer-Verlag, London, 2009.

2. Wee, F. H., M. F. B. A. Malek, S. Sreekantan, A. U. Al-Amani, F. Ghani, and K. Y. You, "Investigation of the characteristics of barium strontium titanate (BST) dielectric resonator ceramic loaded on array antennas," Progress In Electromagnetics Research, Vol. 121, 181-213, 2011.
doi:10.2528/PIER11080815

3. Cristoloveanu, S., "Silicon films on sapphire," Rep. Prog. Phys., Vol. 50, No. 3, 327-371, Mar. 1987.
doi:10.1088/0034-4885/50/3/002

4. Fardin, E. A., A. S. Holland, K. Ghorbani, E. K. Akdogan, W. K. Simon, A. Safari, and J. Y. Wang, "Polycrystalline Ba0:6Sr0:4TiO3 thin films on r-plane sapphire: Effect of film thickness on strain and dielectric properties," Appl. Phys. Lett., Vol. 89, No. 18, Art. No. 182907, Nov. 2006.

5. Jiang, H., B. Lacroix, K. Choi, Y. Wang, A. T. Hunt, and J. Papapolymerou, "Ka- and U-band tunable bandpass filters using ferroelectric capacitors," IEEE Trans. on Microw. Theory and Tech., Vol. 59, No. 12, 3068-3075, Dec. 2011.
doi:10.1109/TMTT.2011.2170088

6. Zhao, Z., X. Wang, K. Choi, C. Lugo, and A. T. Hunt, "Ferroelectric phase shifters at 20 and 30 GHz," IEEE Trans. on Microw. Theory and Tech., Vol. 55, No. 2, 430-437, Feb. 2007.
doi:10.1109/TMTT.2006.889322

7. Meyer, R. G. and M. L. Stephens, "Distortion in variable-capacitance diodes," IEEE J. Solid-State Circuits, Vol. 10, No. 1, 47-54, Feb. 1975.
doi:10.1109/JSSC.1975.1050553

8. Fu, J.-S., X. A. Zhu, J. D. Phillips, and A. Mortazawi, "Improving linearity of ferroelectric-based microwave tunable circuits," IEEE Trans. on Microw. Theory and Tech., Vol. 55, No. 2, 354-360, Feb. 2007.
doi:10.1109/TMTT.2006.889323

9. Chen, K., X. Liu, A. Kovacs, W. J. Chappell, and D. Peroulis, "Antibiased electrostatic RF MEMS varactors and tunable filters," IEEE Trans. on Microw. Theory and Tech., Vol. 58, No. 12, 3971-3981, Dec. 2010.

10. Buisman, K., L. C. N. de Vreede, L. E. Larson, M. Spirito, A. Akhnoukh, T. L. M. Scholtes, and L. K. Nanver, "Distortion-free' varactor diode topologies for RF adaptivity," IEEE MTT-S Int. Microw. Symp. Dig., 157-160, Long Beach, CA, 2005.

11. Huang, C., K. Buisman, M. Marchetti, L. K. Nanver, F. Sarubbi, M. Popadic, T. L. M. Scholtes, H. Schellevis, L. E. Larson, and L. C. N. de Vreede, "Ultra linear low-loss varactor diode configurations for adaptive RF systems," IEEE Trans. on Microw. Theory and Tech., Vol. 57, No. 1, 205-215, Jan. 2009.
doi:10.1109/TMTT.2008.2008978

12. Fu, J.-S., X. A. Zhu, D.-Y. Chen, J. D. Phillips, and A. Mortazawi, "A linearity improvement technique for thin-film barium strontium titanate capacitors," IEEE MTT-S Microw. Symp. Dig., 560-563, San Francisco, CA, 2006.

13. Abdul Khalid, M. F., A. S. Holland, J. R. Scott, and K. Ghorbani, "Analysis of third-order intermodulation distortion in BST varactors," Proc. 2010 Asia-Paci¯c Microw. Conf., 650-653, Yokohama, Japan, 2010.

14. Fardin, E. A., "Barium strontium titanate thin films for tunable microwave applications," , Ph.D. Thesis, School Elect. and Comput. Eng., RMIT Univ., Melbourne, Australia, 2007.

15. Fardin, E. A., A. S. Holland, K. Ghorbani, and P. Reichart, "Enhanced tunability of magnetron sputtered Ba0:5Sr0:5TiO3 thin films on c-plane sapphire substrates," Appl. Phys. Lett., Vol. 89, No. 2, Art. No. 022901, Jul. 2006.
doi:10.1109/TMTT.2005.855141

16. Acikel, B., "High performance barium strontium titanate varactor High performance barium strontium titanate varactor," , Ph.D. Thesis, Dept. Elect. and Comput. Eng., Univ. of California, Santa Barbara, CA, 2002.
doi:10.1109/7260.975716

17. Chase, D. R., L.-Y. Chen, and R. A. York, "Modeling the capacitive nonlinearity in thin-film BST varactors," IEEE Trans. on Microw. Theory and Tech., Vol. 53, No. 10, 3215-3220, Oct. 2005.

18. Tombak, A., J.-P. Maria, F. Ayguavives, Z. Jin, G. T. Stauf, A. I. Kingon, and A. Mortazawi, "Tunable barium strontium titanate thin ¯lm capacitors for RF and microwave applications," IEEE Microw. Wireless Compon. Lett., Vol. 12, No. 1, 3-5, Jan. 2002.

Dr. Muhammad Farid Abdul Khalid

Dr. Ernest A. Fardin

Prof. James R. Scott

Dr. Anthony S. Holland

Prof. Kamran Ghorbani