Maria Carolina Vigano

Sunflower Array Antenna with Adjustable Density Taper

A deterministic procedure to design a nonperiodic planar array radiating a rotationally symmetric pencil beam pattern with an adjustable sidelobe level is proposed. The elements positions are derived by modifying the peculiar locations of the sunflower seeds in such a way that the corresponding spatial density fits a Taylor amplitude tapering law which guarantees the pattern requirements in terms of beamwidth and sidelobe level. Different configurations, based on a Voronoi cell spatial tessellation of the radiative aperture, are presented, having as a benchmark the requirements for a typical multibeam satellite antenna.

Null-matching for the design of linear aperiodic arrays

In this paper the design of linear aperiodic arrays is solved imposing that the nulls of the array factor match those of a Dolph-Chebyschev reference array. With respect to a previous work published by Haupt [R.L. Haupt, 1995], the present technique permits to design aperiodic arrays with an arbitrary number of elements. The maximum sidelobe level achievable with an assigned number of array elements is identified.

Projection based methodology for designing non-periodic, planar arrays

An effective procedure for designing non-periodic, planar array antennas is discussed. It amounts to replicating by orthogonal projection two radiation mask tailored, non-periodic, linear arrays. Meeting the design specifications by these linear arrays guarantees their fulfillment in the entire field of view. The advocated methodology is illustrated by tackling a demanding design problem referring to a satellite communication application, requiring a narrow beam and low side-lobes levels.

Sparse Array Antenna for Ku-Band Mobile Terminals Using 1 Bit Phase Controls

This paper presents a new architecture for low-cost mobile terminal antennas suitable for linear-polarized satellite communications systems. It is based on a sparse phased array that uses 1-bit phase controls. In this way it is possible to reduce the array cost by employing simpler and fewer controls. Measurements of a prototype demonstrate the feasibility of the approach.

A Hybrid Deterministic/Metaheuristic Synthesis Technique For Non-Uniformly Spaced Linear Printed Antenna Arrays

A novel hybrid approach to the synthesis of non-uniformly spaced linear arrays of printed antennas is presented and thoroughly discussed in this paper. In order to account for parasitic mutual coupling between array elements, a dedicated optimization procedure in combination with a multiport network approach is adopted. Selected examples are included in order to assess the effectiveness and versatility of the proposed technique for a wide variety of applications.

Analytical synthesis technique for uniform-amplitude linear sparse arrays

Several approaches to the design of sparse arrays have been proposed in the past [1], mainly based on semi-analytical iterative techniques [2], as well as evolutionary optimization algorithms [3]. Unfortunately, the synthesis procedures already available in the scientific literature lack of generality, and are usually very demanding in terms of computational time and resources. To overcome these limitations, a general and efficient antenna placement technique for linear aperiodic arrays is here presented. Such technique, based on the auxiliary array function concept, allows synthesizing any given radiation pattern mask. The proposed method does not involve any optimization and for this reason it gives almost real-time results. In the presented formulation the array factor is treated by assuming that the mutual coupling between antenna elements is negligible.

Phased arrays with reduced number of phase shifter bits for polarization and pointing control

This paper presents two electronically steered phased array approaches allowing to reduce the number of phase shifter bits required to control steering and polarization. The first approach is based on particular combination of the phase shifters arrangement and elements rotation, while the second introduces a different approach with a combination of simplified phasing approach and aperiodic lattice allowing the number of bits to be reduced to one only. Both approaches have been validated through full scale implementation and measurements results are presented in this paper.

Non-periodic direct radiating arrays for multiple beam space telecommunication missions

This work identifies the non-periodic array configurations for a space multibeam communication satellite which minimise the number of active chains while ensuring a proper control of both the sidelobe (SLL) and grating lobe (GL).

Open-ended triangular waveguide antenna

This communication introduces the open-ended (equilateral) triangular waveguide antenna as a possible elementary radiator for phase-array antenna systems. The proposed structure combines the collinear feeding geometry and the specific aperture shape that would allow for closely packed array architectures required for wide-angle scanning applications. The input matching and the radiation properties of the antenna have been investigated by means of numerical simulations. A possible array arrangement and a feeding strategy have been suggested.

Low-profile tunable radiator for small satellite application

A tunable radiator for space application has been developed to meet stringent requirements in terms of electrical and environmental specifications but also low mass, simple manufacturing and low cost. The element is based on the folded planar inverted F-antenna, with size of one quarter of wavelength. It is mechanically tunable to adjust input impedance for any various positions on the satellite body and possible obstacles and protrusions. Results in terms of radiation pattern, S parameters, shock and vibration tests are presented. The antenna operates in ultra-high frequency band (400 MHz) in linear polarization. It has been designed to act as the basic element for miniaturized multi-function antenna systems on board of small satellites that can operate in three different radiating modes and in both left and right hand circular polarizations.