Preferably, the microwave radiation is at {HEAD ~ a frequency} of {TAIL ~ from twenty to 3000 MHz} 
Preferably , the microwave radiation is at { HEAD ~ a frequency } of { TAIL ~ from twenty to 3000 MHz }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL