A Method for LTCC Resonators to Realize Improved-Resonant Characteristics on Reduced-Size Microstrip Structure

Ramesh K. POKHAREL  Kouji WADA  Osamu HASHIMOTO  Takeshi TAKAHASHI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E87-C   No.9   pp.1517-1523
Publication Date: 2004/09/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Wave Technologies for Wireless and Optical Communications)
Category: Components and Devices
Keyword: 
dielectric rods,  FDTD method,  microstrip resonator,  spurious responses,  attenuation pole,  

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Summary: 
This paper presents a new method to improve the resonant characteristics of a microstrip resonator. The improved characteristics have been achieved by inserting two dielectric rods between strip conductor and the ground plane. Dielectric rods to be inserted have higher relative permittivity than that of the substrate. Therefore, it is suitable to realize by Low-Temperature Cofired Ceramics (LTCC) technique. Several model of microstrip resonators employing the proposed method are analyzed by a Finite-Difference Time-Domain (FDTD) method, and their resonant characteristics are discussed. One of the advantages of the proposed method is that an attenuation pole (fl or fh) in each side of the fundamental resonant frequency (fr) and improved-spurious responses can be realized together by a capacitive-coupling tapped resonator loaded with dielectric rods. The proposed method is also effective to achieve sharp skirt characteristics and wide stopband of a direct-coupling tapped resonator which can be used either as a wideband lowpass filter or a band-elimination filter. Another interesting feature of the analyzed resonators is that about 60% reduction in resonator's length has been obtained compared to a basic half-wavelength (λ/2) microstrip resonator. Therefore, wide exploitation of the proposed method can be expected in the filter design based on the LTCC technique.