Novel Left-Handed Unit Cell for Multi-Band Filtering Applications

In this paper, a new type of left-handed unit cell is proposed, designed for multi-band operation. The proposed unit cell consists of a grounded square metal patch, capacitively coupled to the ring loaded with a grounded inductive stub. By varying some geometrical parameters of the unit cell, its three passbands can be arbitrarily positioned. To demonstrate the applicability of the proposed unit cell, low-loss bandpass filter of the third order has been designed, which exhibits 43% 3-dB fractional bandwidth centred at 5.1 GHz. The proposed filter can be used in modern wireless communication systems that operate according to IEEE 801.11a and HyperLanII standards.