Publication Type:Journal Article
Source:IEEE Microwave and Guided Wave Letters, Volume 10, Number 4, p.136-138 (2000)
Keywords:Bandwidth, Barium strontium titanate, Barium titanate, Dielectric films, Electric field effects, Ferroelectric devices, Gold, Microstrip devices, Permittivity, thin films, Voltage-controlled Lange couplers (VCLC), Waveguide couplers
We report for the first time on the performance of a Au/Ba0.6Sr0.4TiO3 (BSTO)/MgO two-layered microstrip voltage-controlled Lange coupler (VCLC) designed for Ku- and K-band frequencies at room temperature. Tight coupling of 3 dB or higher was obtained over a frequency range of 14–19 GHz. At K-band frequencies, the coupling was voltage-controllable using the nonlinear dc electric field dependence of the relative dielectric constant of BSTO (εrBSTo)- The coupling level was improved from —11.6 to —3.7 dB at 20 GHz with an applied dc electric field of 16 kV/cm. The introduction of the ferroelectric tuning layer enhances the bandwidth of the VCLC in comparison with a Lange coupler with no ferroelectric layer. This work demonstrates another advantageous application for ferroelectric thin films in passive microwave components. © 2000, IEEE. All rights reserved.
cited By 9