After qualifying for GATE you can get work under the following companies:-

1) BSNL Junior Telecom Officer

2) Airport Authority of India

3) Bharat Broadband Ltd.

4) Central Electronic Ltd.

5) National Thermal Power Plant

6) Hindustan Aeronautics Ltd.

7) Delhi Metro Rail Corporation

8) DRDO

These are few of the companies that would hire you and these are the fields you can enter after and ECE graduate degree and GATE.