@inproceedings{ab3bf90615db4d6aaca2f83b8e446a61,
title = "Tunable and high directivity coupler for MRI applications",
abstract = "This paper proposes a tunable and high directivity coupler that is used a RF power monitor in ultra-high field magnetic resonance imaging (MRI) systems. High directivity of a coupler is a critical factor to assure the accurate output in the reflected power measurement. To obtain a tunable and high directivity coupler, a novel directivity tuner includes tunable capacitors and resistors in a passive circuit. A well-tuned capacitance and resistance compensates phase difference and improves directivity in MRI operating frequencies. Therefore, this method significantly reduces the uncertainty of power measurement outputs and can accurately determine reflected power with load variation. The measured results of the proposed coupler agree with the simulation data and achieve excellent isolations (more than 65 dB) and directivities (more than 40 dB) in a compact size of 40 mm × 25 mm.",
keywords = "Tunable coupler, directional coupler, high directivity, magnetic resonance imaging (MRI), power detection",
author = "Sohn, {Sung Min} and Anand Gopinath and Vaughan, {John Thomas}",
year = "2014",
month = jan,
day = "1",
doi = "10.1109/MWSYM.2014.6848491",
language = "English (US)",
isbn = "9781479938698",
series = "IEEE MTT-S International Microwave Symposium Digest",
publisher = "Institute of Electrical and Electronics Engineers Inc.",
booktitle = "2014 IEEE MTT-S International Microwave Symposium, IMS 2014",
note = "2014 IEEE MTT-S International Microwave Symposium, IMS 2014 ; Conference date: 01-06-2014 Through 06-06-2014",
}