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High‐performance cryogenic fractal 180° hybrid power divider with integrated directional coupler
Author(s) -
Ladu Adelaide,
Montisci Giorgio,
Valente Giuseppe,
Navarrini Alessandro,
Marongiu Pasqualino,
Pisanu Tonino,
Mazzarella Giuseppe
Publication year - 2017
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1002/2017rs006292
Subject(s) - power dividers and directional couplers , fractal , hybrid coupler , power (physics) , optics , physics , mathematics , mathematical analysis , quantum mechanics
A 180° hybrid and a directional coupler to be employed in the P‐band cryogenic receiver of the Sardinia Radio Telescope are proposed in this work. An in‐depth study of the issues related to the use of microwave components for cryogenic radio astronomy receivers is carried out to select the best suited technology and configuration. As a result, a planar fractal 180° hybrid configuration available in the literature has been optimized aiming to increase the operating bandwidth in order to comply with the design specifications of the application at hand. A coupled line directional coupler with weak coupling and high isolation, used to calibrate the receiver chain, is cascaded to the 180° hybrid and realized in the same layout. The final device, consisting of the 180° hybrid and the directional coupler, has been manufactured and tested at the cryogenic temperature of 20 K, showing a good agreement between experimental results and predicted performance.