MODELING OF OPEN SQUARE BIFILAR PLANAR SPIRAL COILS
Keywords:Bifilar Coil, Electrical Modeling, Planar Spiral Coil, SelfResonance
In this paper an electrical model for square bifilar planar spiral coils (BPSC) is presented. Its main aim is the study of BPSC electrical parameters and behavior involving the frequency range where the first resonances (valley and peak) occur for bifilar coils in open-circuit configuration. A new approach to determine mutual capacitances of BPSCs based on coplanar waveguide (CPW) lines is presented. This study can be applied for modeling of passive self-resonant (PSR) sensors and wireless power transfer (WPT) systems. In order to validate the proposed model, three BPSCs were manufactured, tested by means of an impedance analyzer and also submitted to electromagnetic (EM) simulations. The results obtained, presented by means of tables and graphs, show that the present study is feasible and promising for the modeling of open square BPSCs.
 W.C. Wysock, J.F. Corum, J.M. Hardesty and K.L. Corum, “Who Was The Real Dr. Nikola Tesla? (A Look At His
Professional Credentials),” Antenna Measurement Techniques Association, pp. 1-5, Oct. 2001.
 C. M. de Miranda, “Equationing and modeling de Tesla’s bifilar coil and its proposal as a biotelemetric self-resonant
sensor,” M.S. dissertation, Dept. Electrical Engineering and Applied Computer Sciences, Federal Univ. of Technology
– Paraná (UTFPR), Curitiba, PR, Brazil, 2012 (in portuguese).
 A. Massarini and M. K. Kazimierczuk, “Self-capacitance of inductors,” IEEE transactions on power electronics, v. 12,
n. 4, pp. 671-676, July 1997.
 C. M. de Miranda and S. F Pichorim,“The Tesla coil as a self-resonant biotelemetric sensor,” in XXIII Brazilian Congress of Biomedical Engineering (CBEB), v. 23, Porto de Galinhas, PE, Brazil, Oct. 2012 (in portuguese).
 M. Ghovanloo and G. Lazzi, “Transcutaneous magnetic coupling of power and data,” in Wiley Encyclopedia of
Biomedical Engineering, M. Akay, Ed. Hoboken, NJ: Wiley, 2006.
 C. M. de Miranda and S. F. Pichorim, "A Self-Resonant Two-Coil Wireless Power Transfer System Using Open
Bifilar Coils," IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 64, no. 6, pp. 615-619, June 2017.
 O. Isik and K.P. Esselle, “Design of monofilar and bifilar Archimedean spiral resonators for metamaterial
applications,” IET Microwaves Antennas & Propagation, vol. 3, n. 6, pp. 929-935, Oct. 2009.
 S. F Pichorim, V. A Marcis and G. T. Laskoski, “Humidity in sandy soil measured by passive, wireless, and resonant
sensor with bifilar coil,” in First Latin-American Conference on Bioimpedance – CLABIO, Journal of Physics:
Conference Series 407, Joinville, SC, Brazil, Oct. 2012.
 D. D. Reis, T. E. Cervi and S. F. Pichorim, “Passive resonant sensor using bifilar coil for moisture measurement on
woods,” in MOMAG 2014: 16th SBMO - Brazilian Symposium on Microwave and Optoelectronics and 11th CBMag
- Brazilian Congress of Electromagnetism, Curitiba, PR, Brazil, pp. 198-203, Sept. 2014. (in portuguese).
 S. F. Pichorim, “Passive, wireless, resonant sensor with open bifilar winding,” Brazilian Patent Application 10 2013
008282-1 A2, April 05, 2013, in Revista da Propriedade Industrial, Rio de Janeiro, RJ, Brazil, no. 2320, p. 96, June
23, 2015. (in portuguese).
 J. Chen and J. J. Liou, “On-chip spiral inductors for RF applications: An overview,” Journal of Semiconductor
Technology and Science, v. 4, n. 3, pp. 149-167, Sept. 2004.
 S. S. Mohan, M. del Mar Hershenson, S. P. Boyd and T. H. Lee, "Simple accurate expressions for planar spiral
inductances," IEEE Journal of Solid-State Circuits, vol. 34, no. 10, pp. 1419-1424, Oct. 1999.
 G. Ghione and C. U. Naldi, "Coplanar Waveguides for MMIC Applications: Effect of Upper Shielding, Conductor
Backing, Finite-Extent Ground Planes, and Line-to-Line Coupling," IEEE Transactions on Microwave Theory and
Techniques, vol. 35, no. 3, pp. 260-267, Mar 1987.
 R. N. Simons, “Coplanar Waveguide with Finite-Width Ground Planes,” in Coplanar Waveguide Circuits,
Components and Systems, New York: John Wiley & Sons, 2001, pp. 112-126.
 C.H. Wu, C.C. Tang and S.I. Liu, "Analysis of on-chip spiral inductors using the distributed capacitance model," IEEE
Journal of Solid-State Circuits, vol. 38, n. 6, pp.1040-1044, June 2003.
 T. Masuda, A. Kodama, T. Nakamura, N. Shiramizu, S.Wada, T. Hashimoto, and K. Washio, “A simplified
distribution parasitic capacitance model for on-chip spiral inductors,” in Digest of Papers. 2006 Topical Meeting on
Silicon Monolithic Integrated Circuits in RF Systems, San Diego, CA (USA), pp. 111-114, Jan. 2006.
 LAB Fit - Curve Fitting Software. Available: http://zeus.df.ufcg.edu.br/labfit
 J. Olivo, S. Carrara and G. De Micheli, “Modeling of printed spiral inductors for remote powering of implantable
biosensors,” in 5th International Symposium on Medical Information and Communication Technology, Montreux,
Switzerland, pp. 29-32, Mar. 2011.
 MATLAB (Matrix Laboratory) software. Available: https://www.mathworks.com/products/matlab.html
 Keysight Advanced Design System (ADS) software. Available: http://www.keysight.com/find/eesof-ads
 X.M. Lopez-Fernández, H.B. Ertan and J. Turowski, “Coreless PCB Transformers,” in TRANSFORMERS: Analysis,
Design and Measurements. Boca Raton, FL, USA: CRC Press, 2013, pp. 537-542.