A 28~38 GHz frequency source for 5G millimeter wave communication

This paper presents a high-precision frequency source for 5G millimeter-wave phased-array system. First, by modeling a phase-locked loop based frequency source, the system simulations are undertaken and the design parameters are obtained. Then the mainly modules including phase frequency detector, charge pump, loop filters, voltage-controlled oscillator and divider are designed and optimized. To eliminate dead zone effects, the phase frequency detector uses a delayed reset chain. By a 5-bit control signal, the output current of the charge pump can be adjustable in order to ensure the output precise of the frequency source. More importantly, a multi-mode multi-core voltage-controlled oscillator is designed to achieve continuous frequency switching and extend the output frequency range. The proposed frequency source can achieve a good tradeoff among the phase noise, frequency arrange and complexity since it can realize the switching of four-core oscillator and four operating modes only at a cost of occupying dual-core area. Simulation results illustrate that a wide frequency range from 28 to 38 GHz can be achieved and the loop locking time is less than 5μs with a deterministic jitter of 205.70 fs. Simulation results also show that the overall power consumption of the frequency source is less than 40 mW, and the output phase noise is about -101 dBc/Hz at 1 MHz frequency offset, meeting the requirements of 5G communication systems.