Affiliations: [a] Missile Institute, Air Force Engineering University,
Sanyuan, China | [b] Department of Computer Science and Technology, Xidian
University, Xi'an, China
Abstract: In this paper, a novel ultra-wide band (UWB) bandpass filter (BPF)
and its equivalent circuit model are presented by etching a Sierpinski carpet
slot on a single negative metamaterial (MTM) transmission line (TL). The MTM
TL, demonstrated with negative permeability within two bands, consists of a
Koch slot etched in the ground plane and a series capacitive gap etched in the
upper stepped-impedance conductor line. The BPF is investigated in depth using
full-wave electromagnetic (EM) simulation, electrical simulation and extracted
constitutive EM parameters. Different geometrical elements on the overall
performance of the filter are also systematically studied. A set of design
guidelines and a simple method to extract lumped-element parameters are
derived, which are of a practical value in future design. For verification, the
developed BPF is fabricated and measured. Consistent results between simulation
and measurement have confirmed the design, showing that the BPF with a relative
bandwidth of 140.3% offers many advantages such as compact size, comparable
low return loss and insertion loss, sharp and deep out-of-band rejection, and
small variation in group delay.
Keywords: Fractals, metamaterial, ultra-wide band (UWB), bandpass filter (BPF), suppression, and group delay
