TASK DEFINITION: Translate the given Spanish text to English
PROBLEM: The center ferquency is tuned by varying the width of the trace.

SOLUTION: La frecuencia central es sintonizada mediante variacion de la anchura de la pista.

PROBLEM: An apparatus (1) for performing the above process is also disclosed.

SOLUTION: También se describe el aparato (1) para realizar el proceso anterior.

PROBLEM: A bendable member defines at least in part the first aperture.

SOLUTION:
Una pieza plegable define al menos en parte la primera abertura.