Novel Compact Meta-Material Tunable Quasi Elliptic Band-Pass Filter Using Microstrip to Slotline Transition

Abstract

In this contribution, a compact ultra wideband band-pass filter with low insertion loss and good rejection using semi complementary split ring resonator is introduced. The 3.0 dB bandwidth is 2.9–8.2 GHz. The minimum and maximum insertion losses in passband are about 0.35 and 1.4 dB at frequencies of 5.4 GHz and 4 GHz respectively in measurement. The bandwidth is tunable via changing the upper 1.0 dB cutoff frequency from 5.0 to 9.0 GHz. The dimensions of this filter (excluding access line for connectors) are about 7.2 × 7.2 mm². The proposed filter is classified in DGS filters group without their problems such as radiation fields from DGS and requiring specific box. In addition, this filter can be used as conventional microstrip filters in commercial and military RF boards. Low-loss and compact behaviors in most frequency of pass-band are interpreted due to the presence of simultaneously negative ε_eff and μ_eff , and then left-handed wave propagation is permitted.