A low phase noise 30-GHz frequency synthesizer with linear transconductance VCO and dual-injection-locked frequency divider

In this paper, a low phase noise 30-GHz frequency synthesizer with a linear transconductance voltage-controlled oscillator (VCO) and dual-injection-locked frequency divider (ILFD) is presented. In order to improve the phase noise of the frequency synthesizer, the LC VCO is designed with transconductance linearization of the active devices. A dual-ILFD is proposed in order to achieve a wide locking range with low power consumption. It is implemented in 65 nm CMOS and the die area is 1.2 mm x 0.8 mm. The power consumption is 55 mW from the supply voltage of 1 V. The measured phase noise of the VCO is respectively -106 and -97.88 dBc/Hz at a 1-MHz offset from carrier frequency of 30.24 and 60.48 GHz. The measured tuning range of the VCO is about 13 %. The locking frequency range of the ILFD is from 14.1 to 45.8 GHz at the injection power of -6 dBm, with its load current being controlled automatically.