A 67 dBm OIP3 Multistacked Junction Varactor

A multistacked varactor is presented for ultra-linear tunable radio frequency applications. The varactor elements are applied in anti-series configuration and are characterized by an "exponential" C-V R relationship. Third-order intermodulation (IM 3 ) is cancelled through proper harmonic loading of the terminals of the anti-series configuration. Multiple stacking is used to further increase the power handling and to minimize the remaining fifth-order distortion. The measured output intercept point (OIP 3 ) at 2 GHz is > 67 dBm for modulated signals up to 10 MHz bandwidth, while providing a capacitance tuning ratio of 3:1 with an average quality factor of 40 and maximum control voltage of 10 V.