International audienceThis paper describes the realization and characterization of microwave 3-D printed loads in rectangular waveguide technology. Several commercial materials were characterized at X-band (8-12 GHz). Their dielectric properties were extracted through the use of a cavity-perturbation method and a transmission/reflection rectangular waveguide method. A lossy carbon-loaded Acrylonitrile Butadiene Styrene (ABS) polymer was selected to realize a matched load between 8 and 12 GHz. Two different types of terminations were realized by fused deposition modeling: a hybrid 3-D printed termination (metallic waveguide + pyramidal polymer absorber + metallic short circuit) and a full 3-D printed termination (self-consistent matched load). Voltage standing wave ratio of less than 1.075 and 1.025 were measured over X-band for the hybrid and full 3-D printed terminations, respectively. Power behavior of the full 3-D printed termination was investigated. A very linear evolution of reflected power as a function of incident power amplitude was observed at 10 GHz up to 11.5 W. These 3-D printed devices appear as a very low cost solution for the realization of microwave matched loads in rectangular waveguide technology

Potassium niobate thin films were grown by pulsed laser deposition on various substrates. Influence of deposition conditions on films characteristics was studied. Structural investigation evidenced that single phase polycrystalline randomly oriented films were grown on sintered alumina whereas epitaxial films were grown on (100)SrTiO 3 and (100)MgO substrates. The microstructure was highly controled by the structural characteristics. Interdigited capacitors built from KNbO 3 films on two different substrates (alumina andMgO) showed the strong influence of the structural characteristics on the dielectric behaviour.The variation of the equivalent capacitance measured on the interdigital capacitor on MgO was 6.4 % at 2.5 GHz while it was 1.5 % on alumina, in both cases for a moderate applied field of ~ 15 kV.cm -1 . The results show the potentiality of this ferroelectric materials for use in frequency agile microwave electronics.

In this study about the relationships between structural and microwave electrical properties of KTa1-xNbxO3 (KTN) ferroelectric materials, a KTN thin film was deposited on different substrates to investigate how KTN growth affects the microwave behavior. Interdigital capacitors and stubs were made on these films through a simple engraving process. Microwave measurements under a static electric field showed the importance of the substrate on the circuit behavior and, notably, on the tuning factor.