DESIGN OF A Ka-BAND COUPLED MICROSTRIP LINE FERROELECTRIC PHASE SHIFTERS

ABSTRACT

We report on the design, fabrication and microwave performance of coupled microstrip line phase shifters (CMPS) based on (Ba,Sr)TiO₃ (BST) thin films for Ka-band phased array antenna. Single phase BST thin films were deposited by pulsed laser deposition (PLD) on (001) MgO substrates. The CMPS were analyzed and designed by using an exact analysis in terms of even and odd mode phase velocities rather than the approach in which the velocities are averaged. These CMPS were tested in Ka-band, at room temperatures, and between the bias ranges of 0∼200 V. The measured differential phase shift was 458° and the insertion loss varied between 7.8 dB and 10.5 dB at 29 GHz in the bias ranges of 5∼200 V. The CMPS exhibited a figure of merit of about 44°/dB.

Keywords:

• Ferroelectric thin films
• coupled microstrip line phase shifters
• even and odd mode
• phase velocity
• phased array antenna

ACKNOWLEDGMENTS

This work was supported by the Minister of Information and Communications Department of Korea.