Microstrip elliptic function filters with compact miniaturized hairpin resonators

A few-pole microstrip elliptic function bandpass filter is designed using compact miniaturized microstrip hairpin resonators. It is shown that the filter has a very small size. The full-wave simulator IE3D is used to design the hairpin resonator, and to calculate the coupling coefficients of the three basic coupling structures. Experimental measurements are performed and the results are compared with the computed response.