Left-handed unit cell based on hilbert grounded patch for multi-band filtering applications

A new multi-band left-handed unit cell which uses Hilbert grounded patch is proposed and compared with the previously reported configuration which uses grounded square patch. The novel unit cell exhibits three distinct passbands and one deep pole. By changing specific geometrical parameters of the unit cell, three passbands can be independently positioned. The Hilbert patch provides an additional degree of freedom in the design of the unit cell: by varying line-to-spacing ratio and its orientation, the tuning range of the second passband can be increased in respect to unit cell with the square patch. To demonstrate the applicability of the proposed unit cell, a wideband bandpass filter of the third order is designed.