Inkjet‐Printed Metal‐Insulator‐Metal Capacitors for Tunable Microwave Applications

Abstract

A Ba 0.6 Sr 0.4 TiO 3 -ZnO-B 2 O 3 composite ink was prepared and used for the manufacturing of fully inkjet-printed metalinsulator-metal varactors. The dielectric thick films were co-fired with printed silver electrodes at 850°C and show a fine grained microstructure. The films have a relative permittivity of e r = 129 and a dielectric loss of tan d = 0.043 at f = 3 GHz. Printed varactors with different dielectric film thickness were prepared. The characterization of the printed structures and 3D electromagnetic simulations of the layout reveal the strong influence of electrode inductance and fringing effects on the properties of the components. The printed varactors reach tunabilities between 14.4% and 16.4% by applying a tuning field of 5 V/lm. To demonstrate the capability of the inkjet printing process for the preparation of tunable microwave devices, a fully inkjet-printed phase shifter was fabricated. It is based on seven pairs of the printed varactors and reaches a phase shift of 180°and a figure of merit of 19°/dB at 3.4 GHz.

Implementation of Ba0.6Sr0.4TiO3‐ZnO‐B2O3 based tunable microwave phase shifters in LTCC technology

“…Interestingly, the FOM has an almost constant level in the frequency range between 0.5 and 3 GHz, which opens a wider application frequency. The maintained performance of the phase shifters (see Table ) in L‐ and S‐band are in good analogy to the phase shifters based on this material on alumina substrates, as can be seen in Table . Additionally, compared to other LTCC‐embedded phase shifters they have shown a significant improvement with regard to the properties as well as the size of the devices …”

“…In recent studies, BST‐ZnO‐B 2 O 3 composite thick‐films have been investigated regarding their suitability as low‐temperature sintered tunable microwave dielectrics . Based on this material, fully screen‐printed MIM capacitors and phase shifters could be fabricated on alumina substrates which showed a considerable improvement compared to other studies . In this paper, the LTCC integration potential of the BST‐ZnO‐B 2 O 3 composites are investigated by the fabrication of LTCC‐embedded phase shifters based on BST thick‐films.…”

Fabrication and Characterization of Fully Inkjet Printed Capacitors Based on Ceramic/Polymer Composite Dielectrics on Flexible Substrates

“…Looking at the recent developments concerning inkjet printing of passive electronic components, such as capacitors or resistors, two main areas can be identified. On the one hand, fabrication of pure ceramic dielectrics for specialized applications, such as tunable microwave components 20,21 . On the other hand, there are various polymer based inks for the fabrication of flexible or stretchable devices, because they need no high temperature sintering process and therefore can be used with polymer substrates 22–24 .…”

Fully Inkjet‐Printed VO2‐Based Radio‐Frequency Switches for Flexible Reconfigurable Components

“…In contrast to the above‐mentioned subtractive technologies, additive manufacturing techniques (inkjet, screen, and 3D printing) offer extremely low cost, completely digital, and highly scalable manufacturing processes . Due to these advantages, additive manufacturing techniques have been used to realize sensors, transistors, RF inductors, RF capacitors, RF filters, RF identification (RFID) tags, and so on. There have only been a few reports on printed RF switches .…”