F. Schettino - Academia.edu (original) (raw)

Papers by F. Schettino

2006 IEEE Antennas and Propagation Society International Symposium, 2006

Based on the results of a numerical investigation, the performance of the parasitic-MIMO system c... more Based on the results of a numerical investigation, the performance of the parasitic-MIMO system can be improved with the introduction of simple and cheap parasitic elements. The introduction of the switchable parasitic elements help to modify the channel introducing a sort of "controllable scatterers" in the close proximity of the active elements. The presence of such new scatterers provides benefits

IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010), 1999

ABSTRACT

Electrical Engineering (Archiv fur Elektrotechnik), 2000

Contents New expressions for the per unit length parameters of transmission lines above conduct... more Contents New expressions for the per unit length parameters of transmission lines above conductive ground planes of finite thickness and finite conductivity have been derived. The results are compared with those deriving from both numerical predictions and approximate, analytical formulae available in literature.

IEEE Transactions on Antennas and Propagation, 2015

ABSTRACT The number of spatial degrees of freedom of the field radiated in a two-dimensional sett... more ABSTRACT The number of spatial degrees of freedom of the field radiated in a two-dimensional setting by a time-harmonic, arbitrary square-integrable current density and in the presence of a random distribution of scattering elements is determined. It is shown that the active power associated to the kth singular value of the near field in the presence of scatterers external to the cut presents a heavy tail decay as a function of its index, rather than the usual exponential attenuation occurring beyond a critical index term observed in free space. This near field “information gain” due to scattering was recently anticipated by Janaswamy using a stochastic source model, it is extended here to arbitrary sources, and it is shown to disappear in the limit of large radiating systems. It is also shown that the same information gain and asymptotic cut-off occurs for the singular values of the field radiating in free space. Collectively, these results show that while the presence of scatterers external to the cut can increase the number of channels that can be exploited for communication by the active power in the near field, they do not change the number of channels associated to the field, nor the asymptotic behavior of the number of degrees of freedom.

2008 IEEE Antennas and Propagation Society International Symposium, 2008

In this paper, an experimental evaluation of the performances of a MIMO-UWB system has been descr... more In this paper, an experimental evaluation of the performances of a MIMO-UWB system has been described. The results obtained show that only at short distances MIMO-UWB systems exploit a significant multiplexing gain. This is mainly due to the SNR of UWB communications. Since the bit rate of UWB at short distances is already very high, non-negligible improvements can be obtained

IEEE International Symposium on Electromagnetic Compatibility. Symposium Record (Cat. No.00CH37016), 2000

The analysis of the current distribution on ground planes of printed circuit boards is carried ou... more The analysis of the current distribution on ground planes of printed circuit boards is carried out by means of a very efficient dual approach and compared with numerical results. The current density inside ground planes of finite thickness is also analytically determined and the per unit length parameters evaluated

International Journal of Modern Physics B, 2000

Passive microwave filters based on HTS films are very promising for telecommunication application... more Passive microwave filters based on HTS films are very promising for telecommunication applications. We report on the design, obtained using a commercial 2.5 D software, and the realization of filters, fabricated with double sided YBCO films grown on LaAlO 3 substrates, for both receiving and transmission systems. For the receiving side, planar multi-pole interdigital L-band filters with 75 MHz transmission bandwidths have been fabricated on 2" substrates. Up to 80 K this kind of filter, based on a Tchebischev response, shows an ...

Many boundary-value problems have been formulated as a system of dual integral equations, and the... more Many boundary-value problems have been formulated as a system of dual integral equations, and the mathematical treatment of such equations is well known. This paper presents a procedure for reformulating a static problem involving a thick structure as a system of dual equations, whose solution is evaluated by means of a Neumann series.

ABSTRACT A preliminary analysis of a reconfigurable parasitic patch antenna for MIMO applications... more ABSTRACT A preliminary analysis of a reconfigurable parasitic patch antenna for MIMO applications is presented. The proposed antenna is able to work on two different polarizations, providing a separate control of the antenna pattern of each of the two polarization. A number of numerical results, showing the adaptive capabilities of the antenna, is given.

2006 IEEE Antennas and Propagation Society International Symposium, 2006

ABSTRACT

2008 IEEE Antennas and Propagation Society International Symposium, 2008

ABSTRACT Leakage from slotted waveguides is a well-known phenomenon and has been thoroughly inves... more ABSTRACT Leakage from slotted waveguides is a well-known phenomenon and has been thoroughly investigated during the past decades. The interest in leaky-wave antennas mainly stems from the possibility of scanning the beam with frequency [1]. The analysis of slotted waveguides has been first performed by means of a transverse network representation of the open structure since the milestone paper by Goldstone and Oliner [2]. As a matter of fact, the method is simple but accurate, and can be easily extended to deal with structures more complicated than the standard slitted waveguide addressed in [2], such as groove guides and stub-loaded waveguides [3]-[5]. Unfortunately it is not always possible to find a transverse equivalent network, in which case it is necessary rely on more general, but time-consuming, numerical methods.

2007 IEEE/MTT-S International Microwave Symposium, 2007

ABSTRACT () α , n P is the Jacobi polynomial of order n, α,β > -1 are parameters to be cho... more ABSTRACT () α , n P is the Jacobi polynomial of order n, α,β > -1 are parameters to be chosen so as to factorise the right edge behaviour of the unknown function, 2c is the width of the generic face and ( ) β α ξ , n is a suitable normalization quantity. The Fourier transform of (1) can be analytically evaluated as an hypergeometric function (4) and results in a generalization of the Neumann series, effectively applied in the analysis of conductive structures (2, 5, 6). It can be shown that the elements of the impedance matrix obtained by applying the Galerkin method with functions (1) can be reduced to single integrals. Moreover their computation can be sped up by means of an analytical accelerating procedure (4). Finally, due to the factorization of the correct singularities of the field, only few terms (usually 2 or 3 terms) are needed in order to achieve accurate results, so that very small matrices have to be dealt with. Moreover, the method can be generalized to non-homogeneous dielectrics, only modifying the Green function of the problem, whilst higher modes can be analyzed by means of the same expansion functions. Finally, the accurate, yet fast, analysis of the problem allows for the evaluation of the p.u.l. parameters of the structure as a function of the geometrical parameters. References

2005 IEEE Antennas and Propagation Society International Symposium, 2005

An efficient method for the analysis of the electromagnetic scattering by perfectly conducting tr... more An efficient method for the analysis of the electromagnetic scattering by perfectly conducting triangular section cylinders is presented. The efficiency of the method stems from the factorization of the right edge behavior of the fields obtained by means of a generalization of the Neumann series. The application of the Method of Moments is therefore not cumbersome nor time consuming.

Passive microwave filters based on high temperature superconducting (HTS) films are very promisin... more Passive microwave filters based on high temperature superconducting (HTS) films are very promising for telecommunication applications. Filters based on a dual-mode configuration present the appealing combination of high power handling capability and excellent miniaturization. Here a new kind of dual-mode filter based on cross-slotted square resonators is presented. The novelty of this structure is related to the use of a pair of unequal crossed slots formed on a square patch resonator, so that the size of the device can be significantly reduced. Single stage dual-mode filters are designed with a commercial 2.5D software at frequencies of interest for satellite communications. Prototypes based on a square resonator with 6 mm side operating at 3.7 GHz are fabricated using Nb double-sided films grown on 10 × 10 × 0.5 mm 3 LaAlO 3 substrates. The response is measured at 4.2 K and the nonlinearity is investigated observing the power degradation. The effect of additional cuts, opportunely realized on the conductor surface, is discussed in respect to the size reduction and the maximum circulating power. It is found that the resonant frequency can be reduced from 3.7 to 3.3 GHz without affecting the power handling capability.

2007 IEEE/MTT-S International Microwave Symposium, 2007

ABSTRACT

Detection and monitoring of water losses has assumed a crucial role in water distribution since t... more Detection and monitoring of water losses has assumed a crucial role in water distribution since the earliest systems were built. In fact the reduction of the water leaks from the distribution pipes and, more in general, the appropriate monitoring and maintenance of the distribution networks is of great interest for the system distributors, that can avoid waste of water and

2009 International Conference on Electromagnetics in Advanced Applications, 2009

We explore the degrees of freedom of M × N user wireless X networks, i.e. networks of M transmitt... more We explore the degrees of freedom of M × N user wireless X networks, i.e. networks of M transmitters and N receivers where every transmitter has an independent message for every receiver. We derive a general outerbound on the degrees of freedom region of these networks. When all nodes have a single antenna and all channel coefficients vary in time or frequency, we show that the total number of degrees of freedom of the X network is equal to MN M+N −1 per orthogonal time and frequency dimension. Achievability is proved by constructing interference alignment schemes for X networks that can come arbitrarily close to the outerbound on degrees of freedom. For the case where either M = 2 or N = 2 we find that the degrees of freedom characterization also provides a capacity approximation that is accurate to within O(1). For these cases the outerbound is exactly achievable. While X networks have significant degrees of freedom benefits over interference networks when the number of users is small, our results show that as the number of users increases, this advantage disappears. Thus, for large K, the K × K user wireless X network loses half the degrees of freedom relative to the K × K MIMO outerbound achievable through full cooperation.

2006 IEEE Antennas and Propagation Society International Symposium, 2006

Based on the results of a numerical investigation, the performance of the parasitic-MIMO system c... more Based on the results of a numerical investigation, the performance of the parasitic-MIMO system can be improved with the introduction of simple and cheap parasitic elements. The introduction of the switchable parasitic elements help to modify the channel introducing a sort of "controllable scatterers" in the close proximity of the active elements. The presence of such new scatterers provides benefits

IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010), 1999

ABSTRACT

Electrical Engineering (Archiv fur Elektrotechnik), 2000

Contents New expressions for the per unit length parameters of transmission lines above conduct... more Contents New expressions for the per unit length parameters of transmission lines above conductive ground planes of finite thickness and finite conductivity have been derived. The results are compared with those deriving from both numerical predictions and approximate, analytical formulae available in literature.

IEEE Transactions on Antennas and Propagation, 2015

ABSTRACT The number of spatial degrees of freedom of the field radiated in a two-dimensional sett... more ABSTRACT The number of spatial degrees of freedom of the field radiated in a two-dimensional setting by a time-harmonic, arbitrary square-integrable current density and in the presence of a random distribution of scattering elements is determined. It is shown that the active power associated to the kth singular value of the near field in the presence of scatterers external to the cut presents a heavy tail decay as a function of its index, rather than the usual exponential attenuation occurring beyond a critical index term observed in free space. This near field “information gain” due to scattering was recently anticipated by Janaswamy using a stochastic source model, it is extended here to arbitrary sources, and it is shown to disappear in the limit of large radiating systems. It is also shown that the same information gain and asymptotic cut-off occurs for the singular values of the field radiating in free space. Collectively, these results show that while the presence of scatterers external to the cut can increase the number of channels that can be exploited for communication by the active power in the near field, they do not change the number of channels associated to the field, nor the asymptotic behavior of the number of degrees of freedom.

2008 IEEE Antennas and Propagation Society International Symposium, 2008

In this paper, an experimental evaluation of the performances of a MIMO-UWB system has been descr... more In this paper, an experimental evaluation of the performances of a MIMO-UWB system has been described. The results obtained show that only at short distances MIMO-UWB systems exploit a significant multiplexing gain. This is mainly due to the SNR of UWB communications. Since the bit rate of UWB at short distances is already very high, non-negligible improvements can be obtained

IEEE International Symposium on Electromagnetic Compatibility. Symposium Record (Cat. No.00CH37016), 2000

The analysis of the current distribution on ground planes of printed circuit boards is carried ou... more The analysis of the current distribution on ground planes of printed circuit boards is carried out by means of a very efficient dual approach and compared with numerical results. The current density inside ground planes of finite thickness is also analytically determined and the per unit length parameters evaluated

International Journal of Modern Physics B, 2000

Passive microwave filters based on HTS films are very promising for telecommunication application... more Passive microwave filters based on HTS films are very promising for telecommunication applications. We report on the design, obtained using a commercial 2.5 D software, and the realization of filters, fabricated with double sided YBCO films grown on LaAlO 3 substrates, for both receiving and transmission systems. For the receiving side, planar multi-pole interdigital L-band filters with 75 MHz transmission bandwidths have been fabricated on 2" substrates. Up to 80 K this kind of filter, based on a Tchebischev response, shows an ...

Many boundary-value problems have been formulated as a system of dual integral equations, and the... more Many boundary-value problems have been formulated as a system of dual integral equations, and the mathematical treatment of such equations is well known. This paper presents a procedure for reformulating a static problem involving a thick structure as a system of dual equations, whose solution is evaluated by means of a Neumann series.

ABSTRACT A preliminary analysis of a reconfigurable parasitic patch antenna for MIMO applications... more ABSTRACT A preliminary analysis of a reconfigurable parasitic patch antenna for MIMO applications is presented. The proposed antenna is able to work on two different polarizations, providing a separate control of the antenna pattern of each of the two polarization. A number of numerical results, showing the adaptive capabilities of the antenna, is given.

2006 IEEE Antennas and Propagation Society International Symposium, 2006

ABSTRACT

2008 IEEE Antennas and Propagation Society International Symposium, 2008

ABSTRACT Leakage from slotted waveguides is a well-known phenomenon and has been thoroughly inves... more ABSTRACT Leakage from slotted waveguides is a well-known phenomenon and has been thoroughly investigated during the past decades. The interest in leaky-wave antennas mainly stems from the possibility of scanning the beam with frequency [1]. The analysis of slotted waveguides has been first performed by means of a transverse network representation of the open structure since the milestone paper by Goldstone and Oliner [2]. As a matter of fact, the method is simple but accurate, and can be easily extended to deal with structures more complicated than the standard slitted waveguide addressed in [2], such as groove guides and stub-loaded waveguides [3]-[5]. Unfortunately it is not always possible to find a transverse equivalent network, in which case it is necessary rely on more general, but time-consuming, numerical methods.

2007 IEEE/MTT-S International Microwave Symposium, 2007

ABSTRACT () α , n P is the Jacobi polynomial of order n, α,β > -1 are parameters to be cho... more ABSTRACT () α , n P is the Jacobi polynomial of order n, α,β > -1 are parameters to be chosen so as to factorise the right edge behaviour of the unknown function, 2c is the width of the generic face and ( ) β α ξ , n is a suitable normalization quantity. The Fourier transform of (1) can be analytically evaluated as an hypergeometric function (4) and results in a generalization of the Neumann series, effectively applied in the analysis of conductive structures (2, 5, 6). It can be shown that the elements of the impedance matrix obtained by applying the Galerkin method with functions (1) can be reduced to single integrals. Moreover their computation can be sped up by means of an analytical accelerating procedure (4). Finally, due to the factorization of the correct singularities of the field, only few terms (usually 2 or 3 terms) are needed in order to achieve accurate results, so that very small matrices have to be dealt with. Moreover, the method can be generalized to non-homogeneous dielectrics, only modifying the Green function of the problem, whilst higher modes can be analyzed by means of the same expansion functions. Finally, the accurate, yet fast, analysis of the problem allows for the evaluation of the p.u.l. parameters of the structure as a function of the geometrical parameters. References

2005 IEEE Antennas and Propagation Society International Symposium, 2005

An efficient method for the analysis of the electromagnetic scattering by perfectly conducting tr... more An efficient method for the analysis of the electromagnetic scattering by perfectly conducting triangular section cylinders is presented. The efficiency of the method stems from the factorization of the right edge behavior of the fields obtained by means of a generalization of the Neumann series. The application of the Method of Moments is therefore not cumbersome nor time consuming.

Passive microwave filters based on high temperature superconducting (HTS) films are very promisin... more Passive microwave filters based on high temperature superconducting (HTS) films are very promising for telecommunication applications. Filters based on a dual-mode configuration present the appealing combination of high power handling capability and excellent miniaturization. Here a new kind of dual-mode filter based on cross-slotted square resonators is presented. The novelty of this structure is related to the use of a pair of unequal crossed slots formed on a square patch resonator, so that the size of the device can be significantly reduced. Single stage dual-mode filters are designed with a commercial 2.5D software at frequencies of interest for satellite communications. Prototypes based on a square resonator with 6 mm side operating at 3.7 GHz are fabricated using Nb double-sided films grown on 10 × 10 × 0.5 mm 3 LaAlO 3 substrates. The response is measured at 4.2 K and the nonlinearity is investigated observing the power degradation. The effect of additional cuts, opportunely realized on the conductor surface, is discussed in respect to the size reduction and the maximum circulating power. It is found that the resonant frequency can be reduced from 3.7 to 3.3 GHz without affecting the power handling capability.

2007 IEEE/MTT-S International Microwave Symposium, 2007

ABSTRACT

Detection and monitoring of water losses has assumed a crucial role in water distribution since t... more Detection and monitoring of water losses has assumed a crucial role in water distribution since the earliest systems were built. In fact the reduction of the water leaks from the distribution pipes and, more in general, the appropriate monitoring and maintenance of the distribution networks is of great interest for the system distributors, that can avoid waste of water and

2009 International Conference on Electromagnetics in Advanced Applications, 2009

We explore the degrees of freedom of M × N user wireless X networks, i.e. networks of M transmitt... more We explore the degrees of freedom of M × N user wireless X networks, i.e. networks of M transmitters and N receivers where every transmitter has an independent message for every receiver. We derive a general outerbound on the degrees of freedom region of these networks. When all nodes have a single antenna and all channel coefficients vary in time or frequency, we show that the total number of degrees of freedom of the X network is equal to MN M+N −1 per orthogonal time and frequency dimension. Achievability is proved by constructing interference alignment schemes for X networks that can come arbitrarily close to the outerbound on degrees of freedom. For the case where either M = 2 or N = 2 we find that the degrees of freedom characterization also provides a capacity approximation that is accurate to within O(1). For these cases the outerbound is exactly achievable. While X networks have significant degrees of freedom benefits over interference networks when the number of users is small, our results show that as the number of users increases, this advantage disappears. Thus, for large K, the K × K user wireless X network loses half the degrees of freedom relative to the K × K MIMO outerbound achievable through full cooperation.