Evaluation of broadband MMIC oscillators with external tank

Abstract: This thesis evaluates broadband Voltage Controlled Oscillators, VCO´s, using different VCO topologies and external tanks. The work has been done at Sivers IMA AB within the "INTOSC" project in the framework of the VINNEX Centre "GHZ CENTRE". Different VCO topologies are investigated and their performance is compared and evaluated. The active part of the VCO, the core, is implemented in a GaAs HBT MMIC technology. The main emphasis of this work has been on the design of the frequency selective off-chip resonance circuit, the "tank", which consists of varactor diodes and bond wires as capacitors and inductors, respectively. Using only two unique MMIC VCO cores, one fundamental and one harmonic MMIC, a family of VCOs covering a frequency range of 2-27 GHz is designed, (in bands) . Most of these VCO`s demonstrates more than octave (2:1) bandwidth. Besides the design and assembly work, analysis of how the tolerances of the critical components in the tank affects the performance of the VCOs are also done within this work.