A novel dielectric resonator bandpass filter with variable attenuation poles for duplexer applications

In this paper a novel dielectric resonator (DR) bandpass filter (BPF) with flexible arrangement of attenuation poles is proposed. This DR filter is similar to a conventional DR filter except adding a microstrip line below a DR, which not only shifts the location of attenuation poles, but also improves skirt characteristics. The duplexer with the proposed DR BPF has been yielded better isolation and sharper skirt behavior than that with a conventional DR filter. The implemented duplexer has shown a good performance and been well agreed with the simulation.