Open AccessMiniaturised tri‐band lowpass–bandpass filter using lumped‐element structure
Author(s) -
Xu Jin,
Wan Hao,
Ding JiangQiao,
Zhu YinXia
Publication year - 2019
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
eISSN - 1350-911X
pISSN - 0013-5194
DOI - 10.1049/el.2018.8054
Subject(s) - passband , band pass filter , low pass filter , high pass filter , prototype filter , electronic engineering , filter (signal processing) , materials science , physics , engineering , electrical engineering
In this Letter, a miniaturised tri‐band lowpass–bandpass (LP‐BP) filter is proposed by using lumped‐element structure. The lowpass passband (LP) and the first bandpass passband (1‐BP) are produced by using the transmission zeros to divide a lowpass filtering response into a dual‐band LP‐BP filtering response. The second bandpass passband (2‐BP) is produced by further loading a lumped‐element circuit. As an example, an LP with 3 dB cut‐off frequency of 1 GHz, and two BPs centred at 2.45/5.2 GHz for the WLAN applications are designed. The fabricated tri‐band LP‐BP filter has low passband insertion losses of 0.08/0.69/1.38 dB, and occupies a compact circuit area of 0.055 λ gc × 0.063 λ gc .