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Fractal Parallel Stacked Inductor using Modified Hilbert Space Filling Curve for RFIC

P. Akhendra Kumar, N. Bheema Rao. Published in Circuits and Systems.

Communications on Applied Electronics
Year of Publication: 2017
Publisher: Foundation of Computer Science (FCS), NY, USA
Authors: P. Akhendra Kumar, N. Bheema Rao

Akhendra P Kumar and Bheema N Rao. Fractal Parallel Stacked Inductor using Modified Hilbert Space Filling Curve for RFIC. Communications on Applied Electronics 7(5):1-4, August 2017. BibTeX

	author = {P. Akhendra Kumar and N. Bheema Rao},
	title = {Fractal Parallel Stacked Inductor using Modified Hilbert Space Filling Curve for RFIC},
	journal = {Communications on Applied Electronics},
	issue_date = {August 2017},
	volume = {7},
	number = {5},
	month = {Aug},
	year = {2017},
	issn = {2394-4714},
	pages = {1-4},
	numpages = {4},
	url = {},
	doi = {10.5120/cae2017652660},
	publisher = {Foundation of Computer Science (FCS), NY, USA},
	address = {New York, USA}


High-Quality factor miniaturized inductors are prerequisites of RFIC Applications. This paper presents a novel fractal stacked inductors using modified Hilbert space filling curve. The parallel stacked inductor with differential excitation improves the Q factor values. The results show more than 50% improvement in Q over conventional fractal inductors maintaining same inductance value with the same occupying area.


  1. LI Baimei, UC Wang, Minglin MA, and Shengqiang Guo. An ultra-low-voltage and ultra-low-power 2.4 ghz lna design. Radio Engineering, 18(4):527–531, 2009.
  2. J. Craninckx and M. S. J. Steyaert. A 1.8-ghz low-phasenoise cmos vco using optimized hollow spiral inductors. IEEE Journal of Solid-State Circuits, 32(5):736–744, May 1997. [3] CongWang and Nam-Young Kim. Analytical optimization of high-performance and high-yield spiral inductor in integrated passive device technology. Microelectronics Journal, 43(3):176 – 181, 2012.
  3. C. P. Yue and S. S. Wong. On-chip spiral inductors with patterned ground shields for si-based rf ic’s. pages 85–86, June 1997.
  4. M. Politi, V. Minerva, and S. C. d’Oro. Multi-layer realization of symmetrical differential inductors for rf silicon ic’s. In 2003 33rd European Microwave Conference, pages 159–162, Oct 2003.
  5. M. Danesh, J. R. Long, R. A. Hadaway, and D. L. Harame. A q-factor enhancement technique for mmic inductors. In 1998 IEEE MTT-S International Microwave Symposium Digest (Cat. No.98CH36192), volume 1, pages 183–186 vol.1, June 1998.
  6. A. Zolfaghari, A. Chan, and B. Razavi. Stacked inductors and transformers in cmos technology. IEEE Journal of Solid-State Circuits, 36(4):620–628, Apr 2001.
  7. W. Y. Yin, J. Y. Xie, K. Kang, J. Shi, J. F. Mao, and X. W. Sun. Vertical topologies of miniature multispiral stacked inductors. IEEE Transactions on Microwave Theory and Techniques, 56(2):475–486, Feb 2008.
  8. G. Haobijam and R. Paily. Quality factor enhancement of cmos inductor with pyramidal winding of metal turns. In 2007 International Workshop on Physics of Semiconductor Devices, pages 729–732, Dec 2007.
  9. Chih-Chun Tang, Chia-Hsin Wu, and Shen-Iuan Liu. Miniature 3-d inductors in standard cmos process. IEEE Journal of Solid-State Circuits, 37(4):471–480, Apr 2002.
  10. A. Maric, G. Radosavljevic, M. Zivanov, L. Zivanov, G. Stojanovic, M. Mayer, A. Jachimowicz, and F. Keplinger. Modelling and characterisation of fractal based rf inductors on silicon substrate. In 2008 International Conference on Advanced Semiconductor Devices and Microsystems, pages 191–194, Oct 2008.
  11. G. Wang, L. Xu, and T. Wang. A novel mems fractal inductor based on hilbert curve. In 2012 Fourth International Conference on Computational Intelligence and Communication Networks, pages 241–244, Nov 2012.
  12. N. Lazarus, C. D. Meyer, and S. S. Bedair. Fractal inductors. IEEE Transactions on Magnetics, 50(4):1–8, April 2014.
  13. G. Shoute and D.W. Barlage. Fractal loop inductors. IEEE Transactions on Magnetics, 51(6):1–8, June 2015.
  14. D. K. Jair, M. C. Hsieh, C. S. Lin, S. M. Chen, and Y. H. Chen. The development of the high performance parallelstacked rf spiral inductor. In 2009 Symposium on Design, Test, Integration Packaging of MEMS/MOEMS, pages 424– 427, April 2009.


High Frequency Structural Simulator (HFSS),Inductance value(L), Modified fractal structure, Quality factor(Q)