A Ka band CMOS LO distribution buffer using transformer-based three-way power divider

抄録

A Ka band CMOS LO distribution buffer with one single-ended input and three differential outputs is presented. In order to split the input power to three differential ones, a new transformer-based unequal differential three way power divider is proposed and adopted. Based on the traditional dual way power divider transformer, an additional concentric winding loop for the third differential output is implemented in the proposed three-way power divider. Two stages of unit differential cascode amplifier are added to boost the gain and isolation. The area of LO distribution network is only 780 µm × 690 µm and thus is more compact. Measurements show that the output buffer offers a 5.8 dB peak gain at 35.7 GHz with amplitude and phase balances better than 6° and 0.5 dB.