In one embodiment, a high frequency quasi optical oscillator power source
is provided which includes an array of amplifier devices each having an
input antenna tuned for a fundamental frequency. A amplifier coupled to
the input antenna amplifies fundamental frequency signals. A multiplier
coupled to the amplifier provides signals at a multiple of the
fundamental frequency and at the fundamental frequency. The output
antenna coupled to the multiplier is tuned at the fundamental frequency
and at a multiple of the fundamental frequency. A grating lobe-to-main
lobe converter located above the array of amplifier devices converts
grating lobe power to main lobe power at the multiple of the fundamental
frequency. A frequency selective reflector opposes the amplifier array to
reflect signals at the fundamental frequency and to pass signals at the
multiple of the fundamental frequency.