Pubblicazioni

Antonio Morini, Giuseppe Venanzoni and Tullio Rozzi, “A new adaptive prototype for the design of side-coupled coaxial filters with close correspondence to the physical structure”, IEEE Transactions on Microwave Theory and Techniques, Vol. 54, no. 3, pp. 1146-1153, Mar. 2006

This paper presents a novel kind of circuit prototype suitable for the modeling of coaxial cavity filters, where all cavities are coupled sidewise. Initially, the parameters of the prototype are explicitly derived from those of the classical Cohn’s in-line filter, which is assumed as starting point. The main feature of the proposed adaptive model is its one-to-one correspondence to the physical structure, making a design feasible without additional optimizations or expensive tuning. Another feature lies in that the prototype is adapted to the structure along the way in the synthesis process. A practical example shows the merits and the accuracy of the proposed prototype. The relationships between the proposed method and existing techniques are also discussed.

Antonio Morini, Tullio Rozzi and Giuseppe Venanzoni, “On the Analysis of Slotted Waveguide Arrays”, IEEE Transactions on Antennas and Propagation, vol. 54, no. 7, pp. 2016-2021, Jul. 2006

A strategy for the full-wave analysis of slotted waveguide planar arrays is presented and demonstrated. The core of the method is a suitable segmentation of the antenna into two fundamental regions: an ‘internal’ one, formed by the waveguide circuit, and the ‘external’ one, consisting of the half space above the plate where the radiating slots are located. The internal region is further segmented into several blocks, connected to each other via their Generalized Admittance Matrices (GAMs). The latter are calculated by means of either a commercial or a home made tool. The front plate is considered as a whole and analyzed by the moment method, in terms of modes of the slots. The latter are considered as short sections of waveguide whose length is just the conductor thickness, connecting the internal and external regions. The approach has been applied with success to a number of large planar arrays, both in rectangular and ridge waveguide.

Antonio Morini, Tullio Rozzi, Marco Farina and Giuseppe Venanzoni “A New Look at the Practical Design of Compact Diplexers”, IEEE Transactions on Microwave Theory and Techniques, vol. 54, no. 9, pp. 3515-3520, Sep. 2006.

This paper presents a method for the design of compact diplexers, where the common junction is considered part of the filters, thus reducing the diplexer length by roughly one cavity. Starting from two filter prototypes satisfying the desired specifications, the technique provides the design equations in closed form. Effectiveness and accuracy of the proposed method are demonstrated by means of a practical example.

Antonio Morini, Giuseppe Venanzoni, Marco Farina and Tullio Rozzi “Practical design of a high-power tuning-less W-band triplexer for ground radar surveillance systems”, IET Microwave and Antennas Propagation, Vol. 1, No. 4, pp. 822-826, Aug. 2007.

The design of a rectangular waveguide 95 GHz (W-band) triplexer for ground radar systems is presented. The triplexer comprises three in-line filters with inductive irises as coupling elements and a manifold formed by three T-junctions. In particular, the scheme proposed is aimed at handling large powers and reducing losses. The triplexer was assembled and measured, showing very good agreement with the simulated results.

Antonio Morini, Giuseppe Venanzoni, Marco Farina and Tullio Rozzi “Modified Adaptive Prototype Inclusive of the External Couplings for the Design of Coaxial Filters”, IEEE Transactions on Microwave Theory and Techniques, vol. 55, no. 9, pp. 1905-1911, Sep. 2007.

The filter prototype of side-coupled coaxial filters, which we recently proposed, has been modified to suit an arrangement in which the coupling apertures are placed on the side opposite the coaxial end-gaps. In this situation, the modified prototype fits the physical counterpart better, resulting in a further design simplification. In addition, the feeds have also been modeled and included into the prototype, thus enhancing the correspondence between the prototype and the physical structure. A practical design, concerning a WIMAX application, shows the reliability of this solution.

Tullio Rozzi , Antonio Morini, Giuseppe Venanzoni, Marco Farina, “Full-Wave Analysis of N-way Power Dividers by Eigenvalue Decomposition”, IEEE Transactions on Microwave Theory and Techniques, Vol. 57, no. 5, pp. 1156-1162, May 2009

An (N+1)-port junction endowed with complete rotational symmetry with respect to the first N ports is analyzed by a partial spectral decomposition of its S-matrix. This approach produces N/2 one-port boundary value problems as well as a single two port problem, which can be easily solved by means of standard full-wave simulators. The practical example of a coaxially fed 36-way power divider was easily analyzed by this method, and the results were nearly indistinguishable from those obtained by analyzing the device as a whole.

Antonio Morini, Tullio Rozzi, Giuseppe Venanzoni, Simona Chiarandini, “On the use of Gegenbauer Polynomials in the Synthesis of Arrays”, IEEE Antenna and Propagation Society International Symposium, 2003, vol. 1, pp. 776-779, 22-27 Jun. 2003

This paper reconsiders the application of the Gegenbauer polynomials to the design of directive linear/planar arrays. The shape of the resulting radiation pattern fits typical specifications better than classical choices, as Gegenbauer profile allows to satisfy the specifications on the sidelobe levels for two distinct angles. In the intermediate region the sidelobe levels decrease, as often required in practice. Therefore, by a suitable choice of the degree and order of the polynomials, it is possible to shape precisely the radiation pattern.

Antonio Morini, Giuseppe Venanzoni, Nickolay Iliev, Tullio Rozzi, Giuseppe Cereda, Barbara Gabbrielli, “A circuit prototype for the design of side and in-line coupled cavity filters in waveguide”, 33rd European Microwave Conference, vol. 3, pp. 1373-1376, 7-9 Oct. 2003, Munich, Germany

This paper presents a new circuit prototype suitable for modelling filters of the topology shown on fig.1, where cavities are coupled to each other either by in-line or side elements. The parameters of the new prototype are explicitly derived from those of a standard in-line filter, which is assumed as reference. The new configuration maintains same response, while the correspondence between circuit parameters and physical structure is one-to-one and of immediate interpretation. A practical example shows the usefulness and accuracy of the proposed prototype.

Antonio Morini, Nickolay Iliev, Giuseppe Venanzoni, Giuseppe Cereda, Barbara Gabrielli, “An effective strategy for the use of commercial full-wave simulators in the design of waveguide filters and diplexers”, 33rd European Microwave Conference, vol. 1, pp. 211-213, 7-9 Oct. 2003, Munich, Germany

The paper presents a strategy for the design of waveguide filters and diplexers, with the help of commercially available 3-D full-wave simulators. The problem in hand is subdivided into an appropriate number of well defined steps, starting from the choice of the circuit prototype to the final full-wave e.m. simulation. The computational effort is adequate and, often, the overall design time for the complete design is reduced to less than1 day. One example, concerning a WR12 filter, employing non standard coupling elements is discussed.

T. Rozzi, A. Di Donato, M. Farina, G. Venanzoni, A. Massaro, "On the use of generalized telegrapher's equations", in Proceedings of SPIE, Conference on Integrated Optics and Photonic Integrated Circuits, April 2004, Strasbourg, France

This paper considers the application of the Generalized Telegrapher’s Equations (GTE) to the electromagnetic modelling and designing of integrated electro-optical devices. This approach allows to eliminate the restrictions introduced by others models, as: weakly guiding condition and isotropic unperturbed medium and to value the modulator time response for a generic modulating signal. The presence of small dielectric perturbations and the large difference between the optical and modulating signal frequencies are the hypotheses considered in deriving the model. The analysis has been applied to a GaAs phase modulator in order to validate the equations and to evidence the effects of the induced anisotropy on the time-domain response. The model can be extended to the analysis of multimode dielectric waveguides, such as independent polarization and directional coupler modulator.

Antonio Morini, Giuseppe Venanzoni, Nickolay Iliev, "A prototype for the design of planar waveguide filters, also containing transmission zeros, with close correspondence to the physical structure", IEEE MTT-S International Microwave Symposium Digest, vol. 2, pp. 467-470, 6-11 Jun. 2004, Fort Worth, TX.

This paper presents a circuit prototype suitable for modeling of planar waveguide filters, where cavities are coupled to each other either by in-line or side elements. In addition, the cross couplings between cavities can be easily included in the model to produce transmission zeros. The parameters of the new prototype are explicitly derived from those of a standard in-line filter, which is assumed as reference. The correspondence between circuit prototypes and physical structures is one-to-one and of immediate interpretation. Some practical examples show the usefulness and accuracy of the proposed prototypes.

Antonio Morini, Tullio Rozzi, Giuseppe Venanzoni, "On the design of slotted waveguide planar arrays", IEEE Antenna and Propagation Society International Symposium, 2004, vol. 3, pp. 3261-3264, 20-25 Jun. 2004, Monterey, CA.

A strategy for the analysis and design of slotted waveguide planar arrays is presented. The core of the method is a suitable segmentation of the antenna into two fundamental parts: one 'internal', formed by the waveguide circuit, and the other 'external', consisting of the half space above the plate containing the radiating slots. The internal part is further segmented into several blocks, connected to each other via their GSM's, while the front plate is analyzed as a whole, in terms of modes of the slots. The two parts are then connected via the modes of the slots, which are considered as pieces of waveguides (whose length is just the conductor thickness). It is then convenient to build a data base containing such GSM's for discrete sets of geometrical parameters. The design reduces to the minimization of a suitable functional, obtained by interpolation of the stored data.
The approach is quite general as the data base can be generated by a commercial tool or/and the internal blocks may consist of waveguides of different shapes (e.g ridge waveguides).

Antonio Morini, Tullio Rozzi, Giuseppe Venanzoni, "Analytical formulas for the design of orthomode transducers", 34th European Microwave Conference, vol. 1, pp. 273-276, 11-15 Oct. 2004, Amsterdam, The Netherlands.

This paper gives analytical formulas for the design OrthoMode Transducers (OMT) providing an accurate synthesis over a band centered at an arbitrary frequency. The method is based on the symmetry properties of six-port junctions, as those used for such components. Although the bandwidth of the device depends mainly on the characteristics of the junction and tapers employed, nonetheless, the method also gives a good starting point for the design of wideband devices. A X-band OMT is finally shown, as an example of application of the above theory.

Antonio Morini, Nickolay Iliev, Giuseppe Venanzoni, "A hybrid method for the construction of the GSM of an arbitrary discontinuity, with respect to pre-selected modes", 34th European Microwave Conference, vol. 3, pp. 1245-1248, 11-15 Oct. 2004, Amsterdam, The Netherlands.

The paper presents a technique, which allows the construction of the GSM of an arbitrary discontinuity with respect to certain pre-selected relevant modes. The discontinuity is embedded between two simple steps, placed either in the E- or H- plane, ensuring that the first N lowest order modes of the new configuration are the ones of interest to the original structure. The new structure is further analyzed by a commercial 3-D EM tool, and the GSM of the embedded discontinuity is recovered by applying a suitable de-embedding procedure. The GSM of the 2 steps are obtained by a modal technique. The procedure described circumvents a number of limitations posed by the direct utilization of 3D EM solvers, which in certain cases may even be not possible.

Antonio Morini, Tullio Rozzi, Giuseppe Venanzoni, "On the Analysis of Waveguide Shunt Slot Arrays", 28th ESA Antenna Workshop on Space Antenna System and Technologies, June 2005, ESA/ESTEC Noordwijk, The Netherlands.

A strategy for the analysis of slotted waveguide planar arrays is presented and demonstrated. The peculiarity of the present approach is that it takes as privileged direction that normal to the radiating slots. In this perspective, a segmentation of the structure is naturally effected at the planes ideally separating the layers forming the antenna. The internal region is further segmented into several blocks, connected to each other via their Generalized Scattering Matrices (GSMs). The latter are calculated by means of either a commercial or a home made tool. It is then convenient to build a data base containing such GSM's for discrete sets of geometrical parameters. The front plate is considered as a whole and analyzed by the Method of Moments (MoM), in terms of modes of the slots. The latter are considered as short sections of waveguide whose length is just the conductor thickness, which constitute the connection between internal and external regions. The approach is quite general as the data base can be generated by a commercial tool and the internal blocks may consist of waveguides of different shapes (e.g. ridge waveguides).

Antonio Morini, Giuseppe Venanzoni, Tullio Rozzi, Marco Villa, "A new prototype for the design of side-coupled coaxial filters with close correspondence to the physical structure", 35th European Microwave Conference, pp. 413-416, 3-7 Oct. 2005, Paris, France.

This paper presents a new mixed lumped-distributed prototype for the design of coaxial filters, in which the cavities are coupled via their side-walls. The element values are explicitly given in terms of the well-known Cohn's direct coupled cavity prototype. The main feature of the proposed model is its one-to-one correspondence to the physical structure, making a design feasible without additional optimizations or expensive tuning. The circuit has been employed in the design of several diplexers, obtaining excellent results.

Antonio Morini, Marco Farina, Tullio Rozzi, and Giuseppe Venanzoni, "An effective strategy for the optimization of the phase distribution of large arrays based on a full-wave model", IEEE Antenna and Propagation Society International Symposium, pp. 4205-4208, 2006, July 2006, Albuquerque, New Mexico.

A practicable strategy for the optimization of large slotted waveguide traveling-wave arrays is discussed. The technique acts directly on the full-wave model of the antenna, recently proposed by ourselves [1]-[3], thus considering all the actual effects such as mutual couplings, thickness and truncation. This is possible owing to the efficiency of the full-wave approach. Optimization is performed on the phases of the feeders -row by row- which the modal voltages across the slots, modeled as section of nearly rectangular waveguides, depend on.

Antonio Morini, Marco Farina, Cristian Cellini, Tullio Rozzi and Giuseppe Venanzoni, "Design of Low-Cost non-radiative SMA-SIW Launchers", 36th European Microwave Conference, pp. 526-529, 10-15 Sept. 2006, Manchester, UK.

This paper presents an effective transition between coaxial and substrate integrated waveguides (SIWs), providing also a method for its design. The transition is not affected by energy leakage, due to unwanted radiation, and it features an adequate bandwidth for many significant applications, e.g. antennas and filters. In addition, the solution is low-cost and the use of Full-Wave methods is reduced to the minimum, with no need of electromagnetic optimization. The design approach can be extended to other structures.

G. Venanzoni, F. Piancatelli, M. Fiorini, C. Cellini, N. Iliev, T. Rozzi,A. Morini, M.Farina, F. Serrano, G. Giunta, M. Montacchiesi, "Un metodo ‘full-wave’ di analisi e progetto dischiere di slot in guida d’onda", XV Riunione Nazionale di Elettromagnetismo, September 2004, Cagliari, Italy.

Con il metodo proposto, l’analisi di array planari di slot in guida d’onda avviene segmentando l’antenna in due parti. Quella ‘interna’, è composta da M giunzioni a N+2 porte, tante quante sono le righe. Ciascuna giunzione è poi formata da una guida d’onda alla cui parete laterale sono connesse N guide della medesima sezione trasversale di ciascuna slot. La parte ‘esterna’ è formata da N X M guide d’onda, ciascuna corrispondente ad una slot, che irradiano su un piano di massa. La parte interna, inoltre, è ulteriormente segmentata in blocchi elementari, uno per ogni slot, interconnessi attraverso la rispettiva GSM. E’ possibile costruire un database che contiene le GSM dei singoli blocchi interni, per un numero discreto di parametri geometrici (distanza dalla mezzeria, lunghezza e larghezza della slot), interpolando il quale si ottiene la GSM per un blocco interno arbitrario, senza ripetere l’analisi full-wave. Il data-base può essere ottenuto anche impiegando un tool commerciale di analisi 3-D. Ciò rende la metodologia valida anche quando le guide impiegate siano di tipo diverso.

Giuseppe Venanzoni, Antonio Morini, Marco Farina, Tullio Rozzi, Cristian Cellini, Marco Villa, "Practical Formulas for the Design of Side Coupled Coaxial Cavity Filters", XVI Riunione Nazionale di Elettromagnetismo, September 2006, Genova, Italy.

This paper presents some practical formulas for the design of combline and side-coupled coaxial cavity filters. Starting from the well known Cohn’s prototype for inline filters, a new prototype with a one to one correspondence to the physical structure is derived using the formulas provided. The latter have been used to derive some prototypes with different bandwidths showing their effectiveness. An example of filter has been designed and simulated by using Ansoft HFSS.

Marco Villa, Giuseppe Venanzoni, "Sviluppo di filtri a fase lineare per applicazioni radar", XIII Giornata di Studio sull'Ingegneria delle Microonde "Progettazione e sviluppo di moderni sistemi di antenna" 14-15 Maggio 2007, Fisciano (Salerno), Italy.

L’articolo presenta lo sviluppo di un filtro a microonde a fase lineare per applicazioni ad elevata potenza. La topologia utilizzata è quella di un filtro a cavità coassiali con le aperture tra le cavità poste sul lato opposto rispetto ai gaps. Nell’articolo vengono discusse le motivazioni della scelta della risposta in frequenza di tipo Bessel e viene illustrata la procedura di sintesi per filtri della topologia scelta. Il dispositivo è stato realizzato e le misure confermano la correttezza della procedura adottata per la sintesi.

Antonio Morini, Marco Farina, Tullio Rozzi, Giuseppe Venanzoni, "Progettazione di array di slot basata su ottimizzazione operante su un modello full-wave", XIII Giornata di Studio sull'Ingegneria delle Microonde "Progettazione e sviluppo di moderni sistemi di antenna" 14-15 Maggio 2007, Fisciano (Salerno), Italy.

L’analisi di array planari di slot in guida d’onda avviene segmentando l’antenna in due parti. Quella ‘interna’, è composta da M giunzioni a N+2 porte, tante quante sono le righe. Ciascuna giunzione è poi formata da una guida d’onda alla cui parete laterale sono connesse N guide della medesima sezione trasversale di ciascuna slot. La parte ‘esterna’ è formata da N X M guide d’onda, ciascuna corrispondente ad una slot, che irradiano su un piano di massa. La parte interna, inoltre, è ulteriormente segmentata in blocchi elementari, uno per ogni slot, interconnessi attraverso la rispettiva GAM (generalized admittance matrix). E’ possibile costruire un database che contiene le GAM dei singoli blocchi interni, per un numero discreto di parametri geometrici (distanza dalla mezzeria, lunghezza e larghezza della slot), interpolando il quale si ottiene la GAM per un blocco interno arbitrario, senza ripetere l’analisi full-wave. La sintesi si riconduce quindi alla minimizzazione di un funzionale, che rappresenta la distanza fra la distribuzione di corrente ideale e quella effettiva, rispetto ai parametri geometrici dell’antenna. La soluzione è molto accurata, in quanto il modello tiene conto di tutte le interazioni che hanno luogo sia nella parte interna che in aria. Inoltre, il metodo è così efficiente che anche il progetto di antenne composte da centinaia di elementi richiede solo qualche ora, su un PC portatile. E’ da notare che il data-base può essere ottenuto anche impiegando un tool commerciale di analisi 3-D. Ciò rende la metodologia valida anche quando le guide impiegate siano di tipo diverso.