Reconfigurable CRLH cells with new open-end stub and RF MEMS switches on silicon technology

Modified CRLH structures implemented on CPW technology and silicon substrate are presented. The aim of this work is to extend the structures frequency agility by adding further tuning capabilities. The classical cell composed of two series interdigital capacitors (IDC) on both sides of a stub-inductor has been modified by adding a new stub capacitor that provides a new degree of freedom by controlling the shunt capacitance CR. Moreover, the IDCs are replaced by switchable MEMS capacitors that allow a variable value of series capacitance. All cells are studied experimentally, in particular for the two actuation states of the MEMS switches, down-state and up-state. The dispersion diagrams covering all the configurations are extracted from equivalent circuit models and hereby presented. They exhibit the flexibility of the Left-Handed (LH) and Right-Handed (RH) frequencies bands. The results analyzed in the 2 - 30 GHz band show up to 15 % of frequency tunability by adding the stub capacitor and up to 150 % by changing the MEMS capacitor state. This approach proves the feasibility of flexible and reconfigurable network based on the present concept.