**5. Conclusions**

A new current-shaping technique to reduce VCO phase noise has been proposed. This method uses a feedback injection mechanism that only uses two transistors and reduces the phase noise as compared to the conventional designs, with a minimum penalty in area and power consumption. To test the proposed solution, simulations were performed and used for evaluation and comparison. Also, a prototype chip fabricated in a 90 nm CMOS process was used to verify the proposed solution. The oscillation frequency can be tuned from 1.72 GHz to 1.83 GHz with an output power of −12 dBm at 1.83 GHz. The power consumption of the core is 3.96 mW. The phase noise results, −112 dBc/Hz at 1 MHz offset, indicates a good agreemen<sup>t</sup> between simulation and measurement.

**Author Contributions:** F.J.d.P.S. and S.L.K. contributed equally to this work. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was funded in part by the Spanish Ministry of Science, Innovation and Universities (RTI2018-099189-B-C22) and by the Canary Agency for Research, Innovation and Information Society (ACIISI) of the Canary Islands Government by ProID2017010067 and TESIS2019010100 grants.

**Conflicts of Interest:** The authors declare no conflict of interest.
