When listing the authors who should be identified on the byline of your article, it is important to ensure all three facets of contribution listed below are met.
 
IEEE considers individuals who meet all of the following criteria to be authors:

1. Made a significant intellectual contribution to the theoretical development, system or experimental design, prototype development, and/or the analysis and interpretation of data associated with the work contained in the article;
2. Contributed to drafting the article or reviewing and/or revising it for intellectual content;
3. Approved the final version of the article as accepted for publication, including references.

Contributors who do not meet all of the above criteria may be included in the Acknowledgment section of the article. Omitting an author who contributed to your article or including a person who did not fulfill all of the above requirements is considered a breach of publishing ethics.

The IEEE Publication Services and Products Board Operations Manual, section 8.2.1.A, provides more information on IEEE’s definition of authorship.