Embedded dielectric resonator filter in layered polymer packaging

This paper describes the creation of a narrowband bandpass filter utilizing an embedded dielectric resonator within bonded layers of polymer substrate. The advantage of this includes a self-packaged design vertically integrated in a compact form. The dielectric resonator, which is buried below the surface of the circuit, maintains a Q in the range of 1100 to 2223 despite the presence of relatively lossy materials surrounding it. Additionally, by removing the substrate surrounding the buried resonator, the redundancies in the degenerate modes of dielectric resonator modes can be separated, effectively creating multiple poles out of a single resonator. Utilizing the redundancies within the buried resonator further decreases the total size of the filter. Analysis on the interaction between dielectric resonator, polymer packaging and bonding agent is necessary to understand the aspects that limit the performance of the filter. An insertion loss of 0.41 dB is measured for a 3.08% bandwidth filter at a center frequency of 11.866GHz.