A linearly polarized omnidirectional planar filtenna at Ku-band is presented in this letter. It is a seamless and incorporate design of an inductive window bandpass filter and a planar coaxial collinear (COCO) radiation element. The radiation element has a linearly polarized omnidirectional radiation characteristic. The substrate integrated waveguide filter is used for RF channel selection as well as a balun. The proposed filtenna has merits of light weight, compact size, low cost, and easy integration with other planar circuits. Simulation and measurement results show that the radiation characteristics of the filtenna keep nearly no change within the working band, while unwanted signals at out-band can be effectively filtered.