Low phase noise division from X-band to 640 MHz

This paper reports on the implementation and performance of a series of analogue, divide-by-two, low noise regenerative dividers (LNRDs) used in cascade to divide an X-band source at 10.240 GHz to 5.12 GHz, 2.56 GHz, 1.28 GHz, and 640 MHz. The X-band source used is a sapphire loaded cavity oscillator with close-in phase noise of L (1 kHz) = -138 dBc/Hz. The phase noise measurements of the divided output signals (at frequencies of 5.12 GHz, 2.56 GHz, 1.28 GHz, and 640 MHz) show close-in phase noise of L (1 kHz) = -145, -149, -153, -157 dBc/Hz, respectively.