High Frequency Power Amplifiers Without Ground

Experimental High Frequency Power amplifiers with fully differential connection to a single-ended device are described. There is no ground connection near the device, and no electrical connection to the heat sink. Common mode choke ferrite sleeve coaxial baluns confine all of the drive and output signal energy to the E and H fields inside the coax connected to the power device. The outside of the coax is not part of the radio frequency circuit. Circuit details and measurements are presented for examples are at 7 MHz, 50 MHz, and a broadband MMIC version from 1 MHz to 3 GHz.