SAW共振子を用いた楕円関数特性を有するバンドパスフィルタの設計に関する一検討

摘要

本研究では，弾性表面波(SAW)共振子を用いたラダー型バンドパスフィルタ(BPF)の直列腕及び並列腕のそれぞれの諸特性を示し，さらに楕円関数BPFについても同様に各腕部の諸特性を示した.それらの特性から共振周波数，減衰極の実現位置及ぴ狭帯域近似法を用いて楕円関数BPFからSAW共振子を用いたラダー型BPFの等価回路への変換を行い，その伝送特性を回路シミュレーションにより確認した.また，SAW共捩子を用いた既存の800MHz帯BPFとの特性の比較を行い，本検討の有用性を確認した.%In this study, we first show each characteristic of a series arm and a parallel arm of a basic ladder-type bandpass filter(BPF) using SAW resonators. The characteristics of each arm of a cascaded type elliptic function BPF are also discussed in a similar way. By using aforementioned characteristics, the conversion from the elliptic function BPF to an equivalent circuit model using the SAW resonators is performed based on a resonance frequency, location of attenuation poles, and the narrow band approximation method. In addition, the comparative examination between the BPF using the proposed method and an existing 800MHz BPF is carried out. As a result, we have confirmed the usefulness of the proposal through our examination.