Microwave regenerative frequency dividers with low phase noise

We demonstrate regenerative divide-by-two (halver) circuits with very low phase modulation (PM) noise at input frequencies of 18.4 GHz and 39.8 GHz. The PM noise of the 18.4 to 9.2 GHz divider pair was L(10 Hz)=-134 dB below the carrier in a 1 Hz bandwidth (dBc/Hz) and L(10 MHz)=-166 dBc/Hz, and the PM noise of the 39.8 GHz to 19.9 GHz divider pair was L(10 Hz)=-122 dBc/Hz and L(10 MHz)=-167 dBc/Hz.