Applied Computational Electromagnetics Society Journal   2016 年 31 卷 8 期

2016

The proposed VCO in this paper is used for multi-mode multi-standard wireless transceiver. The overall scheme includes two VCOs, each VCO adopts transformer-based structure. On-chip transformer which uses coplanar central tap structure and adopts the top metal winding is present. The primary and secondary inductances adopt octagon differential structure. Electromagnetic field (EM) simulation is carried out by using ADS Momentum. Negative conductance unit adopts the current reuse of cross coupled MOSFET. Oscillation mode can be chosen by switch. The primary and secondary inductances of the transformer are connected with 4 bit binary switches capacitor arrays and varactors under different oscillation modes to extend the range of frequency adjustment. Measurement results show that the frequency range is from 1.2 to 7.3 GHz and the phase noise at 1 MHz offset is less than-80 dBc/Hz in the whole frequency range.