The English-language Wikipedia lists her as Infanta Catherine Michelle of Spain.
Her son Thomas Francis founded the house of Savoia-Carignano, the ruling house of Italy from the risorgimento through World War II. Her sister was the Infanta isabel Clara Eugenia.
Her Wikipedia article is here.

1582-1585 Infanta Catalina by Alonso Sánchez Coello (State Hermitage Museum - St. Petersburg Russia)

1582-1584 infanta Caterina Miquela by Alonso Sánchez Coello (Museu Nacional d'Art de Catalunya - Barcelona, Catalunya, Spain)

ca. 1585 Infanta Catalina Micaela by Alonso Sánchez Coello (Museo Nacional del Prado - Madrid Spain)

ca. 1585 Infanta Catalina Micaela by Alonso Sánchez Coello (Museo Nacional del Prado - Madrid Spain) girdle, aiglets, false sleeves, and skirt material

ca. 1585 Infanta Catalina Micaela by Alonso Sánchez Coello (Museo Nacional del Prado - Madrid Spain) hat, coiffure, ruff, and cacanet
