Research Information System
MICROWAVE JOURNAL, vol.57, no.10, pp.76-80, 2014 (SCI-Expanded)
A compact, highly selective, bandstop filter (B SF) is presented with numerical and experimental results. It is additionally modelled with lumped circuit elements in an equivalent circuit model (ECM) to describe resonator coupling and corresponding phase shift. The filter is composed of two electrically small metamaterial cells in the form of fractal resonators. The physical size of the main filtering section is as small as lambda(o)/30 x lambda(o)/14.64, while the total size of the filter with the feed line sections is lambda(o/)10.53 x lambda(o)/6.6. Measurements demonstrate frequency selectivity of 63.80 and 92.10 dB/GHz at the lower and upper frequency band edges, respectively. The passband insertion loss is better than 0.5 dB below 0.6 GHz and above 2 GHz, with a minimum insertion loss of 0.1 dB. The signal suppression level is greater than 20 dB in the frequency band of 1.50 to 1.56 GHz.