Miniaturized slot-line and folded-slot band-pass filters

In this paper the concept of a new class of miniaturized filters using printed circuit technology is presented. The building block of the proposed filter is a miniaturized high-Q printed slot-line resonator, which allows for the realization of both standard coupled-line and cross-coupled quasi-elliptic filters. Each resonator occupies an area as small as 0.03/spl lambda//sub 0//spl times/0.06/spl lambda//sub 0/ and can be shown to have a Q as high as 200 at 2.4 GHz. Analytical, and numerical methods are employed to outline a design procedure. An integral equation full-wave method is used to macro-model the coupling coefficient between two adjacent resonators as a function of their relative distance and orientation. Filter theory is used to design different filter types. The design procedure is validated by comparing the simulated S-parameters of a two-pole and a four-pole Chebyshev filter with those measured from prototypes operating, respectively at 515 MHz and 400 MHz.