During the last twenty
years, the Microwave Microsystem Technology Group of
CNR has matured an expertise in the following areas of the microwave and
millimeter wave devices and sub-systems:
The usual goal of a Research Project led in our Group is the realization
of breadboards for the feasibility release of microwave device configurations:
Recently, the feasibility of microwave and millimeter wave devices has
been released on a number of passive and active configurations. Further to the
activity on devices, the research performed on materials and their processing
for the realization of microwave magnetic and semiconductor integrated
structures is also active.
The Group past and current experience is focused in the following
topics:
Liquid Phase Epitaxy (LPE) and R.F. Sputtering
(RFS) growth of magnetic garnets.
The LPE technique has been optimized to grow thick (> 100 µm), high
magnetic quality pure YIG and subsituted garnet films
for magnetostatic wave (MSW) applications.
The RFS growth has been studied for thin (< 1 µm) films production
and for BiGdAlGa-substituted garnets growth for magnetooptical purposes. Amorphous thin films and multilayers have been also studied from a magnetic,
electrical and optical point of view.
Design and characterization of magnetostatic
wave (MSW) devices.
MSW straight edge resonators (SER) have been designed and characterized
for wideband and narrowband applications, with high unloaded quality factors (Qu » 4000 at 10 GHz). Moreover, dispersive and nondispersive delay lines and coupled resonating structures
have been exploited.
Nonlinear effects at microwave frequencies.
The excitation of solitons and the onset of
instabilities in cw regime as well as in
pulsed regime have been studied for applications in tunable microwave devices.
Frequency multiplication, pulse narrowing, interaction between solitons have been measured and modeled. Nonlinear effects
in periodic structures have been also considered for switching applications.
One more item stressed for millimeter wave applications is the theory
and design of non-linear transmission lines (NLTL) to get pulse compression and
harmonic generation beyond 200 GHz.
Micromachining of Si and GaAs wafers.
Following the increasing market potentialities for micromachined
electromechanical systems (MEMS), the chemical etching of Si and GaAs wafers has been calibrated to obtain configurations
useful for sensors and microwave signal processing. Micro-waveguides and
coplanar waveguides characterized by very low losses and non-dispersive
response at frequencies up to 100 GHz have been obtained.
A general information about the magnetostatic
wave (MSW) technology traditionally performed in this Group and its potential
features for space and ground applications is given in Annex
1.
Results obtained on the micromachining of silicon and GaAs wafers by means of chemical etching techniques to
obtain microwave devices on membranes are presented in Annex
2.
RF MEMS switches and configurations
Intensive studies have been performed in the past decade for assessing
the reliability of the single switch as a building block for configurations
like SPDT for redundancy logic, matrices for signal routing, phase shifters and
TTDL for RADAR applications, reconfigurable filters and antennas
Metamaterial Microwave
Devices
Following the general trend in exploiting the metamaterial
devices for several applications like wideband performances and
miniaturization, we studied antennas, directional couplers, filters an phase
shifters based on the meta-concepts. Interesting results have been obtained
especially for the band-width enlargement, dispersion control, and down-sizing
of antennas and filters in coplanar configurations. Current interests are also
in the non-linear high frequency processing using CRLH structures and
re-configuration solutions.
The facilities available in the Group and the general background on
microwave devices allow an involvement in all the possible ways of cooperation
with an industrial partner:
Design as well as realization and test of breadbords
match our goals. Software Design and Technological Processes can be both
considered part of the every day practice in our
Laboratories.