中文摘要：

利用基于密度泛函（DFT）的第一性原理，计算正交相KNbO3的电子能带结构、复介电频谱图和自发极化，得到KNb03电子能带结构、介电常数以及自发极化，同时得到Nb、O、K各原子之间的成键关系，以及它们在电子能带结构、介电常数和铁电性能中的不同作用，并从理论上分析其介电常数随频率变化以及铁电性能产生的原因．

英文摘要：

Based on density functional （DFT）, this paper calculated the electronic structure, dielectric function, electronic structure, complex dielectric constants and spontaneous polarization in the orthorhombic potassium niobium,and also got the bond types and the effect of the Nb.O.K atoms on these properities as mentioned. At the same time, the reasons why the permittivity varied with the energy of electron and the origin of the ferroelectric property were given.