Gallium Nitride Oscillators+ (GANOSC+)

Start date 01/01/2015
End date The project is closed: 31/12/2016
Motivation
High purity signal generation is a key issue in wireless communication systems and radar systems. The voltage controlled oscillator (VCO) is one of the bottle necks in modern systems using advanced modulation formats like higher order QAM or OFDM.

Currently state-of-the art low-phase noise commercial VCOs are designed in InGaP HBT technology, with key properties for low phase noise such as low flicker noise and relatively high breakdown voltage. A technology with significantly higher breakdown voltage is GaN HEMT. Thus, a voltage-controlled oscillator based on a GaN HEMT can potentially reach very low phase noise.

In GHz centre Stage 3 project GANOSC the potential of GaN HEMT oscillators was demonstrated, however some challenges remain in order to fully benefit from GaN HEMTs high breakdown voltage. The most important of these factors is the flicker noise, which limit near carrier phase noise performance. Other factors are varactor integration and finite Q of integrated resonators.

Objectives
The objective is to forward state-of-the-art performance for oscillators and VCOs in terms of phase noise and tuning range. Output power should be sufficient with reasonable variations over the tuning range. The project has two different tracks, one aiming at integrated oscillators with good phase noise and reasonable tuning range. The other track looks for best possible phase noise using a high-Q external resonator that is compatible with an industrial building practice. In all design work there is an underlying objective to be able to backtrack phase noise contributions.
  • Design of integrated VCOs with good phase noise and reasonable tuning range within the frequency range 7.3-12.3GHz
  • Design of ultra-low phase noise oscillators based on external resonators, e.g., MEMs
  • Low-frequency noise measurements of GaN devices based on different material compositions
  • Investigation of switch-mode oscillators
  • Detailed study of the varactor’s contribution to oscillator phase noise
  • Investigation of switch-mode oscillators
Project outcome
  • 4 articles in high impact journals
  • 3 co-authored (industry/academia) scientific articles
  • 1 PhD
  • MEMs-based VCO module with ultra-low phase noise
  • Low-phase noise medium bandwidth X-band GaN MMIC oscillator
Research Partners
Chalmers, Ericsson, Ruag Space
Project Leaders
Dan Kuylenstierna, Deputy Project Leader: Szhau Lai
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Published: Thu 09 Feb 2017.