Hot Topics in RF & Microwave Engineering

Hi,
I am new to Microwave and RF field and would like to write a review term paper about Microwave topic. Looking for something NOT advanced and easy to understand. Also, would be great if it is related to Communications field.

What are the hot topics that you recommend?


Appreciate very much your help.

Thanks in Advance

Substrate Integrated Waveguides

Periodic structures

Carbon nano tubes

Mems