Metamaterials‐inspired technologies applied to ultra high‐frequency filtering structures

In this letter, the design and comparative study of metamaterial-inspired bandpass filters operating at G-band (150 GHz) is presented. To this aim, filters based on split ring resonators (SRRs) and complementary SRRs are studied and compared on a scale compliant with MMIC technology. Technological issues impose severe constraints to the design of this type of devices. Specifically, the filter selectivity concern is addressed as a trade-off between the acceptable insertion losses in the transmitted band and the achievable bandwidth. The addition of series gaps to previous unit cell configurations and suspended membrane structures are introduced to overcome these limitations, thus presenting improved upper band edges and rejection characteristics. In this context, the extension of metamaterial-based filtering structures to higher frequencies and notably at millimeter waves is still lacking. Therefore, we present here the first contribution in this field by addressing the possibility to fabricate an ultra narrow bandpass filter for space applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1868–1872, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25300