Abstract-This paper presents a narrow-band bandpass filter (NBBPF) using three cylindrical dielectric resonators (CDRs) placed on three rectangular metallic cavities (RMCs). Two U-shaped planar resonators located between RMCs are used to realize narrow-band response effectively. The 3 dB fractional bandwidth (FBW) of the proposed filter is 0.275%. The filter is designed for Xband (9.85 GHz), with 20 MHz bandwidth for radar, satellite, and medical accelerators applications. High Q-factor (Q-factor = 400) and low fabrication cost are other advantages of the proposed design. The proposed NBBPF was fabricated, and its performance was measured to verify the design. Good agreement between the measured and simulated data is obtained.