Study of the different coupling mechanisms between a 4 GHz PPA and a 5–7 GHz LC-VCO

The coupling of the transmitted RF signal of the power amplifier (PA) into the sensitive voltage controlled oscillator (VCO) of a transceiver can cause failure of the RFIC. It is not obvious for the designer to identify which coupling mechanism can be held responsible for the degradation of the VCO. Thus it remains an open problem to decide which appropriate countermeasure should be taken. Different experiments are carried out on a 0.13 mum CMOS 4 GHz PPA and a 5-7 GHz LC-VCO to gain insight in the different coupling mechanisms.