High resolution patterning of LTCC based microwave structures for Q/V-band satellite applications

Highly substrate integrated microwave circuits for space applications require a high metal pattern accuracy for transmission line structures and components. Within this work an embedded 60 GHz strip line filter is used as a demonstrator device to compare four fine line structuring processes for multilayer Low Temperature Cofired Ceramics (LTCC). Fine line screen printing (type I), resinate thin film patterning (type II), laser patterning in green state (type III) and laser patterning of fired screen printed thick films (type IV) are compared regarding pattern tolerances, electrical performance and process implementation capability. All substrates were manufactured using a subsequent tape-on-substrate process (ToS) to embed the filter. The filter measurements exhibit an insertion loss of 4 dB at centre frequencies of nearly 60 GHz for all variations.