please suggest some microwave project

u have alot
antenna
microwave filters , couplers
microwave active circuits LNA , Mixer , Oscillator , Power Amplifier , frequency dividers , and frequency multipliers

or u can do a complete TX , RX :D

it is a very broad topic

U can do design of passive microwave components like directional coupler, circulator, mode converter, RF loads.
U cal also work on Antennas, RF Filter

How about a power scavenging microwave link.

In other words, some sort of communications link, low data rate and very low duty cycle, that derives its DC power by means of:
1) photocell
2) pickup stray RF energy and convert it to DC
3) Pick up vibrational energy
4) Pick up wind power

You might make a perpetual wireless outdoor thermometer/windspeed indicator, or something like that, that never requires you to change its battery.

This is good in that you can use a standard wireless transmitter chip, but have to really pick a good one with low current draw, and have to control it with a picopower microprocessor, and really have to store the energy somewhere and transmit only long enough that you have energy for. It would show your high expertise in a number of electrical engineering areas.