An Improved Distributed Equivalent Circuit Modeling for RF Components by Real-Coefficient AFS Technique

  • Kim, Koon-Tae (School of Electrical and Electronics Eng., Chung-Ang Univ.) ;
  • Ko, Jae-Hyeong (School of Electrical and Electronics Eng., Chung-Ang Univ.) ;
  • Paek, Hyun (School of Electrical and Electronics Eng., Chung-Ang Univ.) ;
  • Kahng, Sung-Tek (Department of Information & Telecommunication Eng., University of Inchoen) ;
  • Kim, Hyeong-Seok (School of Electrical and Electronics Eng., Chung-Ang Univ.)
  • Received : 2010.10.18
  • Accepted : 2011.03.09
  • Published : 2011.05.02


In this paper, a real-coefficient approach to Adaptive Frequency Sampling (AFS) technique is developed for efficient equivalent circuit modeling of RF components. This proposed method is advantageous than the vector fitting technique and the conventional AFS method in terms of fewer samples leading to a lower order of a rational function on a given data and to a direct conversion to an equivalent circuit for PSPICE(Personal Simulation Program with Integrated Circuit Emphsis) simulation, respectively. To validate the proposed method, the distributed equivalent circuit of a presented multi-layered RF low-pass filter is obtained using the proposed real-coefficient AFS, and then comparisons with EM simulation and circuit simulation for the device under consideration are achieved.


  1. Kwang Lim Choi, Nanju Na, and Madhavan Swaminathan, "Characterization of embedded passives using macromodels in LTCC technology", IEEE Transactions Vol 21, No. 3, August 1998.
  2. G. Antonini, “SPICE Equivalent Circuit of Frequency-Domain Responses”, IEEE Trans. on EMC, vol. 45, no.3, pp.502-512, Aug. 2003.
  3. Bjorn Gustavsen "Rational Approximation of Frequency Domain Reponses by Vector Fitting", IEEE Transactions on Power Delivery, Vol. 14, No. 3, July 1999.
  4. S. Kahng, "Prediction of the Radiated Emission(RE)s due to the PCB Power-Bus' Resonance Modes and Mitigation of the RE Levels," Journal of the Korea Electromagnetic Engineering Society, Vol. 7, No. 1, pp.7-11, March, 2007.
  5. S. Song, “Frequency Domain Analysis of Microstrip Filters and Antennae Using an AFS MoM”, IEEE Trans. on Magnetics Vol 42, No 4, April 2006.
  6. Seunghyun Song, Hyeong-Seok Kim, Hyun-kyo Jung, Jeffrey Braunstein and Un-chul Moon, "Frequency domain analysis of microstrip filters and antennae using and adaptive frequency sampling moment method" IEEE Transactions on Magnetics, Vol. 42, No. 4, Apri 2006.
  7. Yonungwook Kim and Hao King, “Equivalent circuit modeling of broadband antennas using a rational function approximation”, Department of Electrical and Computer engineering, The University of Texas at Austin, Nov 2005.
  8. D. Ahn, J.-S. Park, C.-S. Kim, J. Kim, Y. Qian, T. Itoh, “A design of the low-pass filter using the novel microstrip defected ground structure” IEEE Trans. On MTT, Vol. 49, No. 1, pp.86-93, January 2001.

Cited by

  1. Analysis and design of frequency selectivity by layered EBG and metamaterial structure vol.9, pp.5, 2013,