Etienne Girard

EQUIVALENT ELECTRICAL CIRCUIT FOR DESIGNING MEMS-CONTROLLED REFLECTARRAY PHASE SHIFTERS

This article presents an equivalent electrical circuit for designing Radio-Frequency MEMS-controlled planar phase shifter. This kind of phase shifters has recently been incorporated in reconflgurable re∞ectarrays. The proposed equivalent circuit depends on the number, the ON/OFF state and the locations of the switches inside the unit cell. Such equivalent circuit is used for determining, with a little computational efiort, the two important design parameters i.e., the number and the locations of RF-MEMS switches in the phase shifter cell. These two design parameters then allow a designer to design a phase shifter cell having a linear distribution of a given number of phases over 360 - phase range at a single desired frequency.

Phase-Shifting Cell for Dual Linearly Polarized Reflectarrays With Reconfigurable Potentialities

This letter presents a new phase-shifting cell topology for dual linearly polarized reflectarrays. It consists of two orthogonal sets of straight slots etched in a metallic plane and loaded with four capacitances in order to control the phase of the reflected wave. Measurements have demonstrated that the convenient capacitive loading of the central slots permits to provide 331 ° of phase range at 12.5 GHz with linear and parallel dispersions for the different phase states.

A 1.3 m facetted reflectarray in Ku band

Thales Alenia Space and its partners have developed a facetted reflectarray, made of five flat panels arranged along an offset parabolic profile. Faceting the demonstrator is essential for achieving satisfactory RF performances, and especially the largest bandwidth. A 1.3m piecewise reflectarray demonstrator has been designed, manufactured and tested, with a coverage over Canada, US, Puerto Rico and Hawaii. A very good agreement is obtained between the theoretical and measured radiation patterns. Many innovative techniques and processes were developed in order to meet the challenging specifications of a space telecommunication antenna. They are detailed in this article.

Continuous parallel plate waveguide beamformer based on a bifocal constrained lens design

A two-dimensional bifocal constrained lens design is introduced. This is found to be a good starting point for the design of continuous parallel plate waveguide beamformers. The proposed solution has the advantage to provide better scanning performance than the standard pillbox antenna, yet avoiding the complexity of alternative constrained lenses designs. Numerical results are provided to compare the proposed design with existing solutions.

A large imaging array in Ka band with a substrate integrated waveguide Pillbox beamformer

A novel multiple beam antenna is proposed in Ka band. It consists of a dual reflector imaging configuration magnifying a reconfigurable phased array of smaller size, that produce a 2D coverage of multiple spot beams with a quasi-optical beamformer made of Pillbox 1D beamformers.

Imaging system fed by a quasi-optical beam-forming network for Ka-band satellite applications

A quasi-optical system in Substrate Integrated Waveguide (SIW) technology is proposed to feed the primary array of an imaging system for satellite applications in Ka-band. An in-house Physical Optics (PO) tool is used for the complete antenna design reducing the phase aberrations of the imaging system and at the same time improving the Earth coverage by the Satellite. Measurement results validate the overall approach.