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In this letter, a compact, fully uniplanar bandstop filter is presented. It is based on multimodal coplanar waveguide resonators implemented using a slow-wave periodic structure that greatly reduces the filter's horizontal dimension. A multimodal circuit model for the filter is proposed and experimentally validated. A second-order filter prototype at 1.9 GHz, with a compact size of 0.31λ g × 0.19λ g , was designed and fabricated. The filter features measured fractional bandwidths of 9.3% and 3.7% for −20and −30-dB rejection levels, respectively, and a 1.3-dB insertion loss in the passband.Index Terms-Bandstop filter (BSF), multimodal circuit, slow wave, uniplanar.

We aim to explore the nanostructuring potential of a highly focused pencil of ions. We show that focused ion beam technology ͑FIB͒ is capable of overcoming some basic limitations of current nanofabrication techniques and allowing innovative patterning schemes for nanoscience. In this work, we first detail the very high resolution FIB instrument developed specifically to meet nanofabrication requirements. Then we introduce and illustrate some new patterning schemes for nextgeneration FIB processing. These patterning schemes are: 1. nanoengraving of membranes as a template for nanopores and nanomask fabrication; 2. local defect injection for magnetic thin film direct patterning; 3. function of graphite substrates to prepare 2-D organized arrays of clusters; and 5. selective epitaxy of III-V semiconductors on FIB patterned surfaces. Finally, we show that FIB patterning allows "bottom-up" or "organization" processes.