Microwave Inter-Connections and Switching by means of Carbon Nano-tubes

In this work, carbon nanotube (CNT) based interconnections and switches will be reviewed, discussing the possibility to use nanotubes as potential building blocks for signal routing in microwave networks. In particular, theoretical design of coplanar waveguide (CPW), micro‐strip single‐pole‐single‐throw (SPST) and single‐pole‐double‐throw (SPDT) devices has been performed to predict the electrical performances of CNT‐based RF switching configurations. Actually, by using the semiconductor‐conductor transition obtained by properly biasing the CNTs, an isolation better than 30 dB can be obtained between the ON and OFF states of the switch for very wide bandwidth applications. This happens owing to the shape deformation and consequent change in the band‐gap due to the external pressure caused by the electric field. State‐of‐art for other switching techniques based on CNTs and their use for RF nano‐interconnections is also discussed, together with current issues in measurement techniques

Local characterization of ferromagnetic resonance in bulk and patterned magnetic materials using scanning microwave microscopy

We have demonstrated the capabilities of the scanning microwave microscopy (SMM) technique for measuring ferromagnetic resonance (FMR) spectra in nanometric areas of magnetic samples. The technique is evaluated using three different samples, including a yttrium iron garnet (YIG) polycrystalline bulk sample and a thick YIG film grown by liquid phase epitaxy (LPE). Patterned permalloy (Py) micromagnetic dots have been characterized to assess the performance for imaging applications of the technique, measuring the variation of the magnetic properties of the sample along its surface. The proposed technique may pave the way for the development of high spatially resolved mapping of magnetostatic modes in different nanomagnetic and micromagnetic structures

Micromachined magnetostatic wave resonators

A frequency tunable magnetostatic wave (MSW) straight edge resonator (SER) made by a YIG film has been used as a selective frequency component in a micromachined resonating filter. S-parameters have been measured at different DC magnetic bias fields, with a frequency tunability between 2 GHz and 6 GHz ca.. An improvement of the performances for the SERs excited by micromachined microstrip transducers has been clearly demonstrated. Moreover, the utilization of silicon membranes to support MSW-SERs offers important openings toward the integration of magnetostatic wave devices with micromachined structures

Microwave tunable straight edge resonator on silicon membrane

This work presents the experimental realization and the performances of a magnetostatic microwave straight edge tunable resonator (SER) placed on a silicon membrane. The aim of this approach is to study a miniaturised device, integrable in a planar micromachined microwave circuit. S11 and S21 parameters of this device are presented for different magnetic bias fields, exhibiting frequency tunability between 4.2 GHz and 7.25 GHz. The utilization of silicon membranes to support these devices offers important openings toward the integration of magnetostatic wave devices with micromachined structures

38 GHz Antennas on Micromachined Silicon Substrates.

A new configuration of a double folded double slot CPW feed micromachined antenna array was realized on a 1.5 µm thin three-layer dielectric membrane fabricated on a silicon substrate. The antenna was designed for an operating frequency of 38 GHz, and the double folded configuration was used for minimizing the membrane extension

PHASE SHIFTERS BASED ON RF MEMS COPLANAR SHUNT SWITCHES

This paper presents the experimental results obtained on a digital phase shifter based on RF MEMS coplanar shunt switches for radar, beam forming applications. A new design approach is proposed for the design of a digital distributed MEMS phase shifter, and the image parameter representation of two port networks is used to develop an analytical model for this component. Vector network Analyzer measurements have been performed by recording the scattering (S) parameters of the reflected and transmitted signals, and they have been elaborated to get the signal phase shift around the frequency F = 13.7 GHz used for the design. Actually, good performances of the phase shifter have been obtained with respect to the expected ones

Diffusion capacitance effect on the response of monolithic nonlinear transmission lines

In this paper, the effect of the diffusion capacitance upon the electrical performances of the nonlinear transmission lines (NLTLs) is investigated. A comparison between the results obtained for the second harmonic generation by modeling the NLTL with and without the diffusion capacitance is presented. Numerical simulations, performed by means of the harmonic balance method implemented on the Hewlett Packard Microwave Design System Software Package, show significant differences when the diffusion capacitance is included in the NLTL model in comparison with the standard modeling of the NLTL by neglecting this capacitance