The ornamental design for a portableadapter, as shown and described.
1.-2. Portable adapter
1.1 : Front
1.2 : Back
1.3 : Left
1.4 : Right
1.5 : Top
1.6 : Perspective
1.7 : Perspective
2.1 Perspective
1.1 is a front elevation view of a portable adapter (dual mode) showing our new design; 1.2 is a back elevation view thereof; 1.3 is a left side elevation view thereof; 1.4 is a right side elevation view thereof; 1.5 is a top plan view thereof; 1.6 is a perspective view thereof; 1.7 is another perspective view thereof.; 2. 2.1 is a perspective view of a portable adapter (dual mode) showing our new design.
The broken lines in Figures 1.1-2.1 depict portions of the portable adapter that form no part of the claimed design.