As it is a good idea to do PHD from USA and it is a good country which offers you wide range of Universities which provide PHD I would like to share the list with you please feel free to have a look on that

1. University of Dayton - GRE is optional for all engineering programs

2. Stevens Institute of Technology

3. New Mexico state University for Masters in Computer Science

4. University of Nebraska-Lincoln

5. University of Pittsburg - GRE score not required for Materials Science and Engineering

6. University of Northern Virginia in Manassas, VA

7. Purdue University West Lafayette, Indiana

8. MIT-massachusetts institute of technology - Electrical Engineering and computer

9. California State University Sacramento - don't require GRE for Civil Engineering

10. University of Bridgeport, Connecticut - Master's of Science in Computer Science

11. Oklahoma City University, Oklahoma - OCU does not require the GRE or GMAT

12. Farleigh Dickinson University (NJ)

13. Monmouth University (NJ)

14. Montclair State University (NJ)

15. The Richard Stockton College of NJ (NJ)

16. Rowan University (NJ)

17. Wichita State University

18. Kansas State University

19. Virginia State University

20. Florida International University for MS, PhD in Computer Science

21. Villanova University for MS in EE

22. University of Idaho for MS in Environmental science and Computer Engineering

23. West Texas A&M University

24. University of Florida for Arts Education

25. George Mason University (for Masters in Health Information Systems)

26. Revier University