Millimetre wave phase locked oscillator for mobile communication systems

A 56.8 GHz phase locked oscillator has been developed for broadband pico-cell networks in the 62 to 53 and 65 to 66 GHz bands. A set of millimetre wave MMICs has been produced using a 0.25 /spl mu/m HEMT low noise process. A 10 MHz reference is used to stabilise the loop with the help of a low frequency synthesiser at 200 MHz and a sampler at 14.2 GHz. Within the temperature range 0 to 50/spl deg/C, the output signals delivered at 56.8 GHz are higher than the specified 6.5 dBm/spl plusmn/1.5 dB. The phase noise is better than -100 dBc/Hz at 1 MHz from carrier and lower than -70 dBc/Hz at 10 kHz from carrier. A 9 mm/sup 2/ multifunction chip incorporating three basic functions at 55.8 GHz has been implemented. This approach avoids critical connections and demonstrates the capability and maturity of our monolithic technology.<>