Microstrip Transmission Line Loaded by Split-Ring Resonators Tuned by Ferroelectric Thin Film

The resonance frequency of Split-Ring Resonators (SRRs) loading a microstrip transmission line was tuned by means of a BaSrTiO (BST) ferroelectric thin film. For a bias of 30 Volts, we obtained a band-stop response with a shift around 7% of the resonance to higher frequencies in Ku band. The originality of the device under test is (i) the utilisation of single C-shaped SRRs, (ii) the localisation via chemical etching of the BST film to voltage controlled interdigitated capacitances and (iii) the enhancement of the operating frequency (around 17 GHz).