26/40 GHz CMOS VCOs design of radio front-end for 5G mobile devices

In this paper, we propose a radio front end for future 5G mobile devices and present the design and verification of two fundamental voltage-controlled oscillators (VCO) working at potential 5G carrier frequencies. Based on two types of very small on-chip inductors with high quality factor, two LC-VCOs are fabricated and tested in a 130nm CMOS process. With a C-shaped on-chip inductor, VCO 1 achieves a frequency range from 25.23 to 27 GHz, while VCO 2 can be continuously tuned from 39.6 to 41.8 GHz by using a very small horseshoe-shaped on-chip inductor. The measured phase noise for VCO 1 and VCO 2 are -101.9 dBc/Hz and -94.8 dBc/Hz at 1 MHz frequency offset when working at 25.58 GHz and 41.81 GHz respectively, which correspond to FOM of -176.7 dBc/Hz and -172.1 dBc/Hz.