Showing papers by "Luca Perregrini published in 2005"

Efficient calculation of the dispersion diagram of planar electromagnetic band-gap structures by the MoM/BI-RME method

Abstract: The characterization of planar electromagnetic band-gap structures requires the calculation of the dispersion diagram of the modes supported by the periodic structure and the phase of the reflection coefficient under plane-wave illumination. We present a novel method for the calculation of the dispersion diagram. The electromagnetic analysis is based on the method of moments/boundary integral-resonant mode expansion (MoM/BI-RME) method and leads to the formulation of a homogeneous matrix problem. The solution of this problem is performed by an iterative procedure: for a given value of the propagation phase constant, the frequency range is scanned to find the frequencies where the field equation has a nontrivial solution. The search of these frequencies is based on the tracking of the eigenvalues in the complex plane, and proved more efficient than other classical methods (direct search of the determinant zeros, singular value decomposition). The reflection coefficient can be readily determined by using the MoM/BI-RME method, already developed for the analysis of the scattering from frequency selective surfaces. The method is applied to the characterization of the classical uniplanar compact photonic-bandgap structure, and analysis results show the accuracy of the method, its efficiency, and its convergence properties.

Efficient analysis and experimental verification of substrate-integrated slab waveguides for wideband microwave applications

Abstract: This article presents a substrate integrated waveguide, named the substrate-integrated slab waveguide (SISW), which exhibits a wide operation bandwidth. It consists of an integrated rectangular waveguide filled with a periodically perforated dielectric medium. An efficient procedure has been developed for the calculation of the dispersion diagram of SISWs, based on the Floquet theorem, in conjunction with the segmentation technique and the boundary-integral–resonant-mode-expansion (BI-RME) method. Numerical and experimental results confirm the performance of these waveguides and the efficiency of the analysis method. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.

A novel approach for the design of dichroic mirrors for deep space antennas

Abstract: This paper presents a novel approach for the design of inductive dichroic mirrors used in the beam-waveguide feed system of deep-space antennas. The traditional design approach is based on the optimization of the performance of the mirror under single plane-wave illumination at the nominal incidence angle. This methodology does not allow for controlling the radiation pattern transmitted by the feed/dichroic system. A novel design strategy, consisting in optimizing the dichroic mirror also considering the overall feed/dichroic system, permits to overcome the limitation of the traditional approach. A dichroic mirror operating in S/X/Ka band has been designed with the two methodologies and its performance is discussed in the two cases

Design and testing of frequency selective surfaces on thick silicon substrate operating at 600 GHz

Abstract: This paper describes the design and experimental verification of frequency selective surfaces, to be used as quasi-optical filters in the sub-millimeter wave range. They consist of a thin metal layer perforated periodically with rectangular or dogbone-shaped holes, and supported by a thick silicon substrate. A set of filters with pass-band at 600 GHz and stop-band at 750 GHz have been designed and tested. The design procedure based on the MoM/BI-RME method, the manufacturing of prototypes by standard processes available from the semiconductor industries, and their measurement by CW and THz time-domain spectroscopy are reported in this work. This class of filters is mechanically robust, presents low losses (1.4 dB), exhibits good reproducibility, and permits a fine tuning of the stop-band frequency by slightly changing the incidence angle.

S/X/Ka-band dichroic mirrors for deep-space antennas

Abstract: The paper presents two solutions for the design of a 45/spl deg/-incidence S/X/Ka-band dichroic mirror for a European Space Agency ground station supporting deep space missions. The dichroic mirror is required to reflect completely in S band (2.025-2.3 GHz) and X band (7.145-8.5 GHz) and to be transparent in Ka band (31.8-34.7 GHz). The first mirror, consisting of a thick metal screen perforated periodically with rounded rectangular holes, has been fabricated and measured. A second design, based on a metal screen with hexagonal holes, has also been investigated, and it has been proved that this solution provides better overall antenna performance.

Solution of homogeneous electromagnetic problems via the tracking of the matrix eigenvalues: application to the analysis of NRD components

Abstract: This paper presents a novel technique for the calculation of the proper modes of 2D or 3D non-radiating dielectric (NRD) components for mm-wave applications. The novelty of this technique is the use of an integral equation method, in conjunction with a special algorithm for solving the resulting homogeneous matrix problem. This algorithm consists in the tracking of the matrix eigenvalues in the complex plane, when varying either the frequency or the mode propagation constant, and proved to be faster and more reliable than standard approaches, based on the direct search of the determinant zeros. Its effectiveness is demonstrated through the determination of the dispersion diagram of an NRD guide and the calculation of the resonance frequencies of a dielectric resonator.

A Frequency Selective Surface for Harmonic Suppression in THz-Multipliers

Abstract: A quasi-optical filter for harmonic suppression in THz multipliers with a pass-band at 300 GHz and a stop-band at 450 GHz was developed. The filter consists of a 2-dimensional slot array, and is made from microstructured aluminium on an electrically thick, high-resistivity silicon substrate. The filter therefore have a very good mechanical stability and can be manufactured by using reliable processes available from the semi- conductor industries. The design of the filter was based on the MoM/BI-RME method. The frequency response of the filter was optimized for a plane wave with oblique incidence angle and it was shown that fine-tuning of the stop-band can be accomplished by small changes of that angle. Measurements relying on THz- time-domain spectroscopy as well as CW-measurements show an insertion loss smaller than 1.6 dB at 300 GHz and a stop-band attenuation larger than 20 dB at 450 GHz.

Low-loss quasi-optical filters with thick silicon substrates for sub-mm wave frequency multipliers

Abstract: A new class of quasi-optical filters for harmonic suppression in sub-mm wave frequency multipliers with a pass-band at 300 GHz and a stop-band at 450 GHz was developed. The filters consist of 2-dimensional aperture arrays, and are made from microstructured aluminium on electrically thick, high-resistivity silicon substrates. This leads to a very good mechanical stability, low insertion loss, and permits to manufacture the structure by using standard processes available from the semiconductor industries. Two quasi-optical filters, the former with rectangular slots and the latter with dogbone-shaped holes, have been designed by using the MoM/BI-RME method. Several prototypes have been fabricated, and measured by THz-time-domain spectroscopy and CW-measurements, showing an insertion loss smaller than 1.6 dB at 300 GHz and a stop-band attenuation larger than 20 dB at 450 GHz. High reproducibility of the structures has also been proved. Moreover, it was shown that fine-tuning of the stop-band can be accomplished by small changes of the incidence angle.

Low-loss frequency selective surfaces on silicon substrates for sub-millimeter wave applications

Abstract: A new class of frequency selective surfaces (FSSs), to be used as quasi-optical filters for harmonic suppression in sub-mm wave frequency multipliers, is proposed and experimentally verified. The FSSs consist of two-dimensional aperture arrays, and are made from microstructured aluminium on electrically thick, high-resistivity silicon substrates. This leads to a very good mechanical stability, low insertion loss, and permits the structure to be manufactured using standard processes available from the semiconductor industry. The paper presents the design, fabrication, and testing of two sets of prototypes, the former with a pass-band at 300 GHz and a stop-band at 450 GHz and the latter with a pass-band at 600 GHz and a stop-band at 750 GHz.

Electrical analysis of NRD components by a novel eigenvalue-tracking technique

Abstract: This paper presents a novel technique for the calculation of the proper modes of 2D or 3D nonradiating dielectric (NRD) components for mm-wave applications. The novelty of this technique is the use of an integral equation method, in conjunction with a special algorithm for solving the resulting homogeneous matrix problem. This algorithm consists in the tracking of the matrix eigenvalues in the complex plane, when varying either the frequency or the mode propagation constant, and proved to be faster and more reliable than standard approaches, based on the direct search of the determinant zeros. Its effectiveness is demonstrated through the determination of the dispersion diagram of an NRD guide and the calculation of the resonance frequencies of a dielectric resonator.