Design of Diplexer Using Surface Acoustic Wave and Multilayer Ceramic Filters with Controllable Transmission Zero

Shinpei OSHIMA
Hiroto MARUYAMA

Publication
IEICE TRANSACTIONS on Electronics   Vol.E104-C    No.8    pp.370-378
Publication Date: 2021/08/01
Publicized: 2021/01/15
Online ISSN: 1745-1353
DOI: 10.1587/transele.2020ECP5033
Type of Manuscript: PAPER
Category: Microwaves, Millimeter-Waves
Keyword: 
transmission zero,  diplexer,  matching circuits,  lumped elements,  

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Summary: 
In this paper, we propose a design method for a diplexer using a surface acoustic wave (SAW) filter, a multilayer ceramic filter, chip inductors, and chip capacitors. A controllable transmission zero can be created in the stopband by designing matching circuits based on the out-of-band characteristics of the SAW filter using this method. The proposed method can achieve good attenuation performance and a compact size because it does not use an additional resonator for creating the controllable transmission zero and the matching circuits are composed of only five components. A diplexer is designed for 2.4 GHz wireless systems and a global positioning system receiver using the proposed method. It is compact (8.0 mm × 8.0 mm), and the measurement results indicate good attenuation performance with the controllable transmission zero.