Li, Qiao2016-02-122016-02-122015-12https://hdl.handle.net/11299/177142University of Minnesota Ph.D. dissertation. December 2015. Major: Electrical Engineering. Advisor: Anand Gopinath. 1 computer file (PDF); vii, 90 pages.Recently, 60GHz system is a hot topic for its large unlicensed bandwidth and small component size. However, some components could not be integrated into the 60GHz communication subsystem either because of their large size or poor performance after integration. One of the most popular ways to build a planar device at high frequency with low cost is to use substrate integrated waveguide (SIW). To make a planar device with low loss at the millimeter waveband, first a 60GHz substrate integrated waveguide with taper transitions from microstrip lines are designed and fabricated. Although planar ferrite isolators based on SIW have been successfully built, all of them work below 20GHz because the ferromagnetic resonance frequency of the traditional ferrite, Yttrium-Iron-Garnet (YIG) is low. Here, to develop a 60GHz isolator based on SIW, a novel C-axis M type Barium thin film ferrite is used. The experimental results proved that the ferromagnetic resonance frequency of this thin film ferrite is much higher than the traditional ferrite materials. In this way a 60GHz H-plane resonance isolator based on SIW is realized with low insert loss and high isolation in the working waveband. Moreover, by integrating a ferromagnetic thin film with ferroelectric thin film, a tunable 60GHz isolator based on SIW was realized. The working frequency of the isolator can be varied with the voltage bias. This method makes it possible to build voltage controlled ferrite devices at 60GHz, which is important for large bandwidth systems.en60GHzbarium ferriteresonance isolatorsubstrate integrated waveguidetunable deviceThesis or Dissertation