What will be the size of antenna to transmit 20 gigahertz frequency to the free space. Share with your friends Share 0 Sanjay Singh answered this Dear student velocity of electromagnetic wave isc=f×λ3×108=20×109×λλ=3×10820×109=1.5×10-2minimum height of antenna is h=λ4=1.5×10-24=0.325×10-2mRegards 0 View Full Answer