Monica Righini

A Multilayer PCB Dual-Polarized Radiating Element for Future SAR Applications

The design, manufacturing, and testing of a slot-coupled multilayer dual-polarized X-band radiating element is presented. The proposed architecture provides an isolation between polarization ports better than 34 dB over a 16% frequency band. The selected technology is particularly suitable for large-scale, low-cost, and high reliable manufacturing. This work has been carried out in the frame of a research program funded by the Italian Space Agency and aimed to the development of enabling technologies exploitable in next-generation spaceborne synthetic aperture radar (SAR) antennas.

Fringe Currents Evaluation on a Perfectly Conducting Wedge Illuminated by an Elementary Dipole

The field generated by an elementary dipole in presence of a perfectly conducting wedge can be expressed analytically through a double infinite series. The series convergence gets critical when the observation point and the source are close to each other. In this letter, an improvement of that analytic solution, attained by extracting Greens function singularity, is presented, speeding up series convergence and allowing efficient computation of fringe currents, which are the corrective terms, taking into account diffraction, to physical optics current.

A dual band circularly polarized square patch for indoor positioning systems

This paper presents the development and characterization of a dual-band left hand circularly polarized square mi-crostrip antenna for WiFi applications (2.45GHz and 5.20 GHz) with a single feed point. The proposed design is achieved via a central slot and four symmetrical T-shaped slits on the patch sides. The antenna is then arranged in a cubic set-up for MIMO applications. Experimental results are presented.

Closed form expressions for the realistic modeling of weakly directive antenna patterns

In this paper a set of analytical expressions useful to model the pattern of printed antennas in a behavioral manner is proposed. Despite their simplicity, the proposed functions are computationally simple and well suited for fitting antenna measurement, hence useful to be implemented when a fast response is required, as in early stage of feasibility study.

Efficient tolerance analysis on a low cost, compact size, wideband multilayer patch antenna

A compact and low cost multilayer patch antenna, with a band of the order of 14%, is presented. An efficient tolerance analysis is proposed to assess expected real world performances from simulated data. A prototype has been manufactured and a comparison of the simulation and measurement results is shown.

A CIRCULARLY POLARIZED ANTENNA FOR DUAL BAND OPERATION AT 2.45 GHZ AND 5.10 GHZ

This paper describes the design and experimental characterization of a circular polarized printed antenna for dual-band WiFi operation at 2.45GHz and 5.10GHz. The patch design is based on a combination of slits loading and gap-coupling applied to a disc patch in order to enhance the radiation performances in terms of polarization purity and bandwidth at the two operation frequencies. Experimental validations confirm a maximum gain around 6.0 dB for both 2.45and 5.10GHz, as well as an axial ratio as low as 0.5 dB and a return loss exceeding 15 dB on the operating frequencies. These characteristics are suitable for operationing in IEEE802.11x networks.

Electromagnetic Scattering of a Dipole Field by a Perfectly Conducting Wedge

The scattering problem of the electromagnetic field generated by an elementary dipole in the presence of a perfectly conducting wedge is here addressed in terms of a Sommerfeld integral which can be expressed by an infinite summation. The analytic solution presented is valid also in the case in which the dipole, the observation point, or both are close to the edge of the wedge. Approximations are also presented, and comparison with the uniform geometrical theory of diffraction (UTD) solution provided.

A Fully Integrated Multilayer Power Distribution Network for SAR Dual-Polarized Linear Arrays

The design, manufacturing and testing of a planar technology, fully integrated, multilayer, dual-polarized power distribution network, feeding a six element X-band linear array is presented. The selected technology, not used yet for space applications, is particularly suitable for large scale, low cost manufacturing. The proposed architecture provides an isolation between the two polarizations better than 40 dB, an input ports return loss better than 25 dB, and a 0.6 dB worst case amplitude unbalancing with a maximum phase shift of about 9 degrees between output ports, within a 16.7% bandwidth.