Conference Paper

High Q tunable cavity using dielectric less RF-MEMS varactors

CNRS, Univ. de Limoges, Limoges, France
Conference: Microwave Conference, 2009. EuMC 2009. European
Source: IEEE Xplore

ABSTRACT This paper presents first experimental results on high Q MEMS tunable microwave cavity using RF-MEMS switched varactors. MEMS varactors that have been used in this work are based on a dielectric less tunable cantilever actuator, with good reliability and well-established fabrication process. It is shown that one can obtain large Q using type of component, with measured Qu between 550 and 850 for a tuning range of 500 MHz around 5 GHz.

0 Bookmarks
 · 
55 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Innovative concepts are presented for both miniaturized high-selectivity and MEMS-based reconfigurable waveguide filters recently developed. The aim is to reduce size and weight of satellite telecommunication systems without compromising the high unloaded Q required in such applications. A first class of new miniaturized filters is based on ridges arbitrarily located and oriented within a waveguide. The ridges behave as quasi-TEM resonators and allow for pseudo-elliptic filter responses. A second class of very compact waveguide filters employs TM dual-mode cavities as building blocks to generate N th order filters with N transmission zeros. Two new concepts have then been developed for high-Q bandpass filters with tunable central frequency or bandwidth using RF MEMS. Cantilever MEMS switches are suitably arranged in a rectangular waveguide so as to change either the TE101 mode resonant frequency or the coupling between E-plane filter resonators. Both approaches are shown to yield higher unloaded Q (~1000) than previous approaches involving RF MEMS along with ridged or conductor-loaded cavities.
    01/2011;
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents a 14 GHz high-Q (quality factor) tunable resonator using microelectromechanical system (MEMS) varactors. A brass surface mountable cavity has been bonded on a fused silica wafer on which are processed three 1.1 mm long MEMS varactors. Their location has been optimized in order to obtain a wide frequency shift, when the cantilevers are actuated on the substrate. 15% tuning range from 11.9 GHz to 14.2 GHz has been obtained with a continuous shift from 11.9 GHz to 13.6 GHz. Measurements result in an average unloaded quality factor (Qu) of 480 over the operating frequency band.
    IEEE Microwave and Wireless Components Letters 05/2011; 21(5):237-239. · 1.78 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents an innovative concept for the design of MEMS-reconfigurable bandpass filters with very high Q-factor. MEMS switches are arranged at one or both sides of a TE<sub>101</sub> mode cavity so as to provide an equivalent reconfigurable inner waveguide wall. The effective width of the cavity can be changed by activating the MEMS switches, so as to control the cavity resonant frequency. The proposed method yields higher Q-factors with respect to other approaches involving ridged or conductor-loaded cavities. Preliminary measurements of a 10 GHz 4<sup>th</sup> order bandpass filter show a 400 MHz frequency shift with a Q-factor above 900.
    Microwave Conference (EuMC), 2010 European; 10/2010