Open AccessA Novel Broadband Microwave Lumped-Element Quadrature Hybrid MMIC
Author(s) -
Xi Chen,
Anyong Hu,
Jianhao Gong,
Ruochen Gu,
Wangdong He,
Jungang Miao
Publication year - 2022
Publication title -
ieee access
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 127
ISSN - 2169-3536
DOI - 10.1109/access.2022.3192128
Subject(s) - aerospace , bioengineering , communication, networking and broadcast technologies , components, circuits, devices and systems , computing and processing , engineered materials, dielectrics and plasmas , engineering profession , fields, waves and electromagnetics , general topics for engineers , geoscience , nuclear engineering , photonics and electrooptics , power, energy and industry applications , robotics and control systems , signal processing and analysis , transportation
In this paper, a novel broadband lumped-element quadrature hybrid MMIC for interferometric correlation radiometer is proposed. First, the cause of the bandwidth limitation in the lumped-element branch-line coupler is analyzed, which is the two identical parallel branches have the same frequency response leading to reinforced resonance and narrow band. In order to reduce such unfavorable superposition effect, parallel branches with opposite frequency responses are used, which exhibits the characteristic similar to rat-race coupler. To realize a quadrature hybrid, a phase-shifting network is cascaded to the rat-race coupler, and the bandwidth is further extended by compensating the passband phase trend and optimizing the inter-stage matching of the two parts. Finally, to facilitate the application, the quadrature hybrid is combined with a variable gain amplifier to implement an integrated MMIC based upon 0.15 $\mu {\mathrm{ m}}$ GaAs pHEMT process, and the size of the hybrid part is $1.2\times 1.4$ mm2. Within the frequency range of 3.8~8.5 GHz (75% fractional bandwidth), the amplitude and phase imbalance are less than 0.5 dB and 2.6°. All reflections and isolations are better than 16.4 dB. The measured results verify the design theory and illustrate that the lumped-element quadrature hybrid is suitable for compact broadband circuit applications.