Design of Compact Ultra-Wideband Filter with Low Insertion Loss and Wide Stopband

Hui-I WU  Zhao-Zhu WONG  Christina F. JOU 

Publication
IEICE TRANSACTIONS on Electronics  Vol.E93-C  No.9  pp.1481-1483
Publication Date: 2010/09/01
Online ISSN: 1745-1353
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Microwaves, Millimeter-Waves
Keyword: 
wideband,  wide-stopband,  selectivity,  compact, 

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Summary: 
This paper proposes a compact ultra-wideband filter, which skillfully utilizes the magnetic and capacitive coupling to obtain sharp rejection. And, the filter contains a small number of lossy elements, thus the low insertion loss and compact size will not be compromised. The measured results show that the filter prototype has a measured 3 dB fractional bandwidth of 128% from 2.8 GHz to 11.4 GHz, a minimum insertion loss of 0.3 dB within the passband, a superior 20 dB stopband rejection from 12.4 GHz to 24 GHz, and a very compact circuit size of 0.23λ0.31λ, where λ is the guided wavelength of the microstrip structure at the center frequency f0 = 7.1 GHz.