Ther syllabus of gate 2020 will include the following topics-

1. Genrral aptitude and reasoning.

2. Engineering Mathematics-

Linear Algebra

Calculus

Differential Equations

Vector Analysis

Comolex Analysis

Numerical Methods

Probability and Statisdtics

3. Network, signals and systems-

Network solution methods

Continuous time signals

4. Electronic Devices

5. Analog circuits

6. Digital circuits

7. Control systems 

8. Communications.

For the detailed syllabus, you can refer to their official syllabus page, here is the link-

gate.iitm.ac.in/Syllabus