Temperature and voltage impact on intermodulation distortion of planar barium strontium titanate varactors

Measured capacitance vs. voltage data along with measured 3^rd-order intermodulation distortion (IMD) data at various bias and temperatures are presented for interdigital barium strontium titanate varactors. A dip/sweet spot is observed in the 3^rd-order intermodulation distortion products when plotted vs. input RF power. The dips occur at RF power levels near 20 dBm and are an important consideration for large signal applications of BST varactors. Shifts in the dip are reported as the bias voltage is varied from 0-50V. Non-linear modeling methods are also discussed.