THE DESIGN AND FABRICATION OF A HIGHLY COMPACT MICROSTRIP DUAL-BAND BANDPASS FILTER

A highly miniaturized 2.45/5.7 GHz dual-band bandpass filter is presented in this paper. It shows that the proposed filter which combines different sizes of open-loop resonators can excite two desired passbands. With the meandered technology and fractal geometry, the overall size is extremely compact compared with the published dual-band bandpass filters. Furthermore, the skirt selectivity of the proposed filter with two transmission zeros locating at both sides of the passbands is much improved. The rejection of the spurious response from 6.7 GHz to 14.5 GHz is successfully suppressed to the level lower than -15dB. The occupied area of the proposed filter is 9.8×8.7 mm2. The measurement is in good agreement with the simulation