Multi-standard/Multi-band Distributed VCOs for SDR applications

The paper thoroughly describes the operation of a wideband Distributed VCO (DVCO) which allows to design VCOs with a good trade off among wideband and phase noise. The general condition of oscillation is reported. Two innovative tuning techniques are proposed and described. Each solution has been used to design and fabricate a DVCO prototype. The first one is a simplified Printed Circuit Board prototype based on the switched-capacitors banks tuning technique. It provides a tuning range of 360 MHz from 1.52GHz to 1.88GHz sub-divided in two sub-bands: 1.52-1.78GHz and 1.69-1.88GHz The second one is a fully integrated VCO which adopts the new approach called “switched-cells tuning technique”. It provides the following measured tuning range subdivided in four sub-bands: 207MHz around 900MHz, 291MHz around 1.5GHz, 392MHz around 1.8GHz and 199MHz around 2.4GHz. According to the reported theory, the results show the applicability of the proposed Distributed VCOs for advanced transceivers.