Eur. Phys. J. D (2013) 67: 68
https://doi.org/10.1140/epjd/e2013-30068-0

Regular Article

Investigation on capacitively loaded microstrip line

¹ Department of Physics, Sharif University of Technology, P.O. Box 11365-9567, Tehran, Iran
² Young research club, Islamic Azad University, Bonab branch, Bonab, Iran
³ Department of Physics, Faculty of Sciences, Azarbaijan Shahid Madani University, 53714-161 Tabriz, Iran
⁴ Department of Laser and Optical Engineering, University of Bonab, 5551761167 Bonab, Iran

^a e-mail: h.masalehdan@gmail.com, masalehdan@azaruniv.edu
^b e-mail: siavash.lotfi@yahoo.com

Received: 26 January 2012
Received in final form: 6 December 2012
Published online: 5 April 2013

Abstract

In this work, a microstrip transmission line with a planar left-handed structure, is investigated. Negative μ is achieved by creating periodic capacitive slots in the conducting strip of line. By using the transmission matrix method for periodic structures, these slots are analyzed. To this end, the unit cell is considered as a combination of two series capacitors and a section of transmission line, and then the transmission matrix of this unit cell is calculated. The dispersion relation verifies the existence of a stop band with a negative magnetic permeability (μ < 0) below the cut-off frequency. The width of stop band can be controlled by changing the structure dimensions.