Investigation on capacitively loaded microstrip line

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