Design of Bandpass Filters with a Function to Control the Number of Attenuation Poles

Kouji WADA  Yasuhisa YAMAMOTO  Osamu HASHIMOTO  

IEICE TRANSACTIONS on Electronics   Vol.E85-C   No.3   pp.578-585
Publication Date: 2002/03/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Signals, Systems and Electronics Technology)
Category: Circuit
attenuation pole,  stub resonator,  bandpass filter,  tap-connection technique,  

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New bandpass filters (BPFs) with stub resonators are proposed for creating multiple attenuation poles. Firstly, the stub-dependent characteristics of the distributed-element stubs are examined theoretically. Secondly, the new BPFs with resonators of combined stubs are proposed. An advantage of these filters is the possibility of controlling the number of attenuation poles. The design of the proposed filter is carried out based on the general filter design with the narrow-band approximation technique. The transmission and reflection characteristics of the proposed BPFs are also examined theoretically and experimentally. The miniaturization of the filters is also carried out using the resonator with loaded-element stubs. The discussions lead us to the conclusion that the proposed design method of the filters are useful for controlling the number of attenuation poles of the BPF.