Garcia,Garcia J; Bonache,J; Gil,I; Martin,F; Marques,R; Falcon,F; Lapetegi,T; Laso,M A G; Sorolla,M(Microwave and Optical Technology Letters, February 20, 2005)
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Abstract:
In this paper, microstrip lines magnetically coupled to splitring
resonators (SRRs) are conquved to electromagnetic bundgup (EBG)
nr,rrostrip lines in terns q/ their stop-heard penjbrnmrnce and dimensions. In
bath types o/ trunsmis•siou lines, signal propagation is inhibited in it certain
jequency bwuL For EBG microstrip lines, the central frequency of such a
forbidden band is determined by the period of the structure, whereas in
SRR-hased microstrip lines the position of the frequency gap depends on
the quasi-static resonant frequency of the rings. The main relevant conrributiun
of this paper is to provide a tuning procedure to control the gap width
in SRR microstrip lines, and to show that by using SRRs, device dimensions
ale much smaller than those required by EBGs in order to obtain similar
stop-banal performance. This has been demonstrated by fill-wave electromagnetic
simulations and experimentally verified from the characterization
ql two fabricated microstrip lines: one with rectangular SRRs etched on the
upper substrate side, and the other with a periodic perturbation cf'strip
width. For similar rejection and 1-(;H,. gap width centered at 4.5 Gllz, it
has been found that the SRR microstrip line is•,fve times shorter. In addition,
no ripple is appreciable in the allowed band for the .SRR-hared structure,
whereas due to dispersion, certain mismatch is expected in the EBG
prototype. Due to the high-frequency selectivity, controllable gap width, and
small dimensions, it is believed that SRR coupled to planar transmission
lines can have an actual impact on the design of stop-band filters compatible
with planar technology, and can be an alternative to present solutions based on distributed approaches or EBG