Rapid prototyping of LTCC microwave circuits using laser machining

In this paper the use of laser machining for the rapid prototyping of microwave circuits in LTCC technology is studied. Compared with traditional screen printing or photolithographic methods, a fast and low cost method for circuit research and development is feasible by directly patterning conductors and vias using a commercial laser prototyping system on unfired LTCC green-tape. The effects of varying laser power, etching speed and etching grid are studied. A conductor width and gap of 50 mum are successfully realized with edges that are clean cut with a definition of plusmn 5 mum. A via with diameter of 50 mum is also realized. A band-pass ring resonator and a coupled-line band-pass filter are fabricated using this technique and the results are compared with simulation.