Magnetically coupled series-tuned air coil resonators having very low C/L ratios to achieve higher QL, lower insertion loss and improved out-of-band rejection

摘要

A series tuned resonator circuit topology permits implementation of narrow band-pass filters having higher loaded quality factors (QL) and lower insertion loss than was previously achievable in the prior art employing such a topology. The topology employs an additional parallel capacitor for the series-tuned topology, with very low C/L ratios to achieve the combination of higher values of QL, low insertion loss and a steeper roll-off between the pass-band and the stop-band (at both lower and higher frequencies). Air coils are used to achieve the large inductor values desirable for the series-tuned topology.