Since you are in your 4th year, you should try anything related to Microprocessors or Micro controllers.You can also try making an audio amplifier which is connected to a speech processing unit.
All the Best.
Maybe something related to software defined radio. That's the way radio is going, has gone. Mix right down to baseband. Digitize I and Q signals, use various forms of modulation. Maybe even digitize directly after the RF amp with the lastest and greatest A/D converters, using DSP filtering packaging, and screw the mixer.
Check out "development boards" offered by Analog Devices, Maxim, and others; and build upon them.