FPD'17

D1P7 - TRP - Widely-tunable MEMS LC tank for Wideband Oscillators - Fondazione Bruno Kessler (IT), RF uTECH (IT)

14 Feb 2017, 16:20

40m

Newton 1 & 2 (ESA/ESTEC)

Speaker

Mr Benno Margesin (Fondazione Bruno Kessler (IT))

Description

The scope of the activity was to demonstrate that the Micro-electro-mechanical (MEMS) system technology is able to provide resonators that combine a good phase noise control with wideband tunability, i.e. resonators with a high quality factor. The main target performance were: - Centre frequency 9 GHz 4.5 GHz - Phase noise @ 100 kHz <-105 dBc/Hz <-111 dBc/Hz - Phase noise @ 1 MHz <-130 dBc/Hz <-136 dBc/Hz - Tuning range >15 % >15 % - Output RL <-10 dBm <-10 dBm - Output level +10 dBm +10 dBm In the first phase two different resonator concepts, a planar concept based on the FBK RF MEMS technology and concept based on 3D metal cavities combined with MEMS varactors in planar technology were investigated. For both concepts, prototype resonators were designed, fabricated and measured. The resonator in planar technology resulted to be the best approach. In parallel a preliminary design of the wideband VCO was studied. The most promising approach was a Clapp architecture for which an experimental mock-up was made. The tests validated the design und simulation procedure for the oscillator. In phase two an optimized version of the LC tank design was realized together with 2 variants of a new design that made use of spiral inductors suspended in air. In order to further reduce the losses and guarantee high Q-values the devices were partially suspended on 50 µm thick silicon membranes obtained by integrating in the fabrication process a DRIE process module. Probe measurements of the MEMS resonators showed that the most promising design is the compact LC tank based on spiral inductors and a capacitive dual gap varactor. The final oscillator is based on commercially available electronic components mounted on dedicated circuitry boards on which the MEMS resonator is directly mounted and wire bonded. The functional tests included a full characterization of the phase noise, the frequency tuning range and the assessment of the thermal stability of the devices. The best results obtained are: - Oscillation frequency 2.6 GHz - Phase noise @ 100 kHz -104.5 dBc/Hz - Phase noise @ 1 MHz -120.4 dBc/Hz - Tuning range >20% ![enter image description here][1] ![enter image description here][2] [1]: https://indico.esa.int:443/indico/event/170/picture/1.jpg [2]: https://indico.esa.int:443/indico/event/170/picture/2.jpg

Short Speaker Information

Benno Margesin: Expert in MEMS and microfabrication technologies. Responsible for the RF MEMS process development and for the fabrication of the prototypes. He was the coordinator of the project.