Amro Elshurafa, et al., "Two-layer radio frequency MEMS fractal capacitors in PolyMUMPS for S-band applications." Micro & Nano Letters 7, (5), 2012, 419.
In this Letter, the authors fabricate for the first time MEMS fractal capacitors possessing two layers and compare their performance characteristics with the conventional parallel-plate capacitor and previously reported state-of-the-art single-layer MEMS fractal capacitors. Explicitly, a capacitor with a woven structure and another with an interleaved configuration were fabricated in the standard PolyMUMPS surface micromachining process and tested at S-band frequencies. The self-resonant frequencies of the fabricated capacitors were close to 10 GHz, which is better than that of the parallel-plate capacitor, which measured only 5.5 GHz. Further, the presented capacitors provided a higher capacitance when compared with the state-of-the-art-reported MEMS fractal capacitors created using a single layer at the expense of a lower quality factor.