Investigation and optimization of transitions in an LTCC based RF MEMS switching matrix for space applications

For communication purposes in space applications big switching matrices combining several inputs with corresponding outputs, are needed. The usual switching matrix approach uses mechanical switches, which are reliable, but bulky and heavy. New approaches try to employ RF MEMS switches, which are not only small and lightweight, but also do not require much power and are extremely linear. Usually the RF MEMS switches are realized as silicon chips, embedded into a suitable substrate for realizing the entire matrix, e.g. LTCC. A modular approach is here favorable, as it gives much flexibility together with compact elements. The drawback of this kind of circuit is the need for numerous transitions, e.g. to connect the input and output pins to the substrate, to bondwire the chips into the substrate, to transit from layer to layer in the multilayer LTCC. The very promising performance of the RF MEMS switches can therefore deteriorated very strongly, if these transition components are not designed and optimized properly. In this contribution optimized and compensated transitions are introduced for use in an LTCC circuit combined with RF MEMS switches at frequencies up to 20 GHz. New designs and improvements will be introduced and the sensitivity of the whole circuit performance for these components will be investigated.