Compact low loss alumina band-pass filter in Ku band using layer-by-layer stereolithography technology

Based on layer-by-layer stereolithography, a small sized 2-pole filter in Ku band is designed and manufactured. Experimental and electrical performances are in good agreement with the computations performed and validate the use of such technology in the fabrication of microwave filters. Employing a standard metallization method for such structures is also confirmed. A 2-pole bandpass filter, of 35 mm
²
area and 2 mm height, is achieved. Nevertheless, the insertion losses are excellent and less than 1 dB while the return losses are better than 20 dB. The unloaded quality factor is 1650. On the other hand, a theoretical study of a 4-pole filter centered at 17.5 GHz is also presented.