Electrical Prism: A High Quality Factor Filter for Millimeter-Wave and Terahertz Frequencies

A 2-D electrical filter is introduced that is compatible with today´s conventional integrated circuit processes. The rich 2-D propagation properties of the medium are used to introduce a novel high quality factor filter called an electrical prism. The proposed filter shows a quality factor much larger than the quality factor of the individual components at high millimeter-wave and terahertz frequencies. This structure also provides a negative effective index in a low-pass LC lattice. Based on this idea, we show filters with quality factors of 130 at 230 GHz and 420 at 460 GHz consisting of elements with the quality factor of 10 and 20, respectively. The effect of component loss on the filter quality factor is discussed in this paper. The negative effective index and the filter behavior of the lattice is verified by measuring a prototype on a CMOS process at 32-40 GHz. There is good agreement among the theory, simulation, and experimental results.