A High LO-to-RF Isolation 34-53 GHz Cascode Mixer for ALMA Observatory Applications
Journal
IEEE MTT-S International Microwave Symposium Digest
Journal Volume
2018-June
Pages
686-689
Date Issued
2018
Author(s)
Abstract
This paper presents the implementation of a downconversion single-ended mixer fabricated by 0.1-μ m GaAs pHEMT process with wide IF bandwidth, high LO-to-RF isolation, and low LO power for ALMA band-l applications. The mixer is a single-ended cascode structure using cold bias (VDS =0) mixing core for wide IF bandwidth, and LC resonators to restrict LO power coupling to the RF port. According to the measurement, the proposed mixer performs well conversion gain, good gain flatness, and wide IF bandwidth with 0 dBm LO power in 34-53 GHz RF frequency which covers ALMA band-l. The measured LO-to-RF isolation is better than 37 dB. The LC resonated technology successfully solves the main drawback of poor LO-to-RF isolation of single-ended mixers. Compared with published works, the proposed single-ended mixer shows lower LO power and competitively high LO-to-RF isolation which is better than conventional single-ended mixers and comparable to balanced mixers. ? 2018 IEEE.
Subjects
Bandwidth; Cascode amplifiers; Crystal resonators; Gallium arsenide; III-V semiconductors; Resonators; ALMA band-1; Cascode; cold bias; LC resonators; pHEMT; RF isolation; Single-ended; Analog circuits
Type
conference paper