To be Ph. d graduate you need to complete post graduation that is master's degree or else must have completed engineering on the subject you prefer. After you complete the above graduation then you have to follow some few regular steps to enroll yourself for Ph. d.
1) Eligibility completion or going to complete BE/B.Tech. or ME/M.Tech. in Engg (any branch including CS/ECE EE/Civil/Inst./Biotech.) or B.Arch. or Master's degree in Science/Maths/IT/ICT/Computer Science or MCA.
2) Select the university which you wish to enroll for Ph.d.
3) Follow their rules for registration. Most probably all the universities have an entrance exam to qualify for this degree.
4) There will be two papers
Paper I: General aptitude paper
Paper II: Subject paper
Paper I will include basic aptitude, logical reasoning, basic questions on mathematics.
Paper II will include ECE Paper Syllabus: Networks, Electronic Devices, Analog Circuits, Digital circuits, Control Systems, Signals and Systems, Probability theory and random processes, Communication Theory, Digital Signal Processing,
5) The fees may be approx 20 to 25 thousand per month for regular, distance or vacation students will have a different fee structure.
6) Before you enroll select an experienced guide for your fellowship and some details like DTP operator for typing your thesis.
These are the basic requirements for applying Ph.d. I hope your doubts are cleared if any other clarification then raise another query with this link.