electronic specializations for computer students

i am a student of computer science engineering(3year).i want to take my electronic specialization in my m.tech.this is because of my interest.i am interested in mathematics and physics(specially electromagnetism).i humbly ask you to send a list of all m.tech or m.s specializations in my higher education which matches my interest.....so that i could enjoy my study and also my job in the future.....also tell whether job opportunities and salaries for those specializations are comparable or greater than software field........i am in great dilemma and tensed about my future ..because of wrong decision in choosing computers in b.tech.i sincerely ask to give the above information along with a detailed career counseling....understand my problem sir.....
give a detailed explanation sir.........
thanking you ASHWIN