embodiments include semiconductor devices related to compound varactor circuits . specifically , a semiconductor device may be constructed of a modified anti - series string of varactor pairs , wherein one varactor in a varactor pair has an effective area larger than the other varactor . varactor pairs in the anti - series string are arranged such that adjacent varactors coupling varactor pairs have equal effective areas . in some embodiments , the anti - series string may have four varactors in other embodiments , the anti - series string may have eight varactors or twelve varactors . the compound varactor using the modified anti - series string of varactor pairs may be advantageous in reducing second harmonics related to parasitic capacitances in anti - series varactor applications .