This paper proposes a new design methodology of arbitrarily shaped integrated lens antennas (ILAs). First, we describe the design principles and numerical techniques of the optimization iterative loop. The starting lens shape, deduced from a general synthesis method based on geometrical optics principles, is optimized so that the radiation pattern of the ILA complies with an arbitrary amplitude-shaped template. The optimization procedure is local and is based on a multidimensional conjugate gradient method. Then, the capabilities and potentialities of this approach are demonstrated numerically using two examples. In the first one, an ILA radiating a secant-squared beam in one principal plane and a flat-top beam in the orthogonal plane is designed for indoor communications in V-band. In the second example (Gaussian/flat-top beam), we show for the first time that the joint optimization of the feed together with the lens shape is a very promising design methodology. Finally, our design tools are validated experimentally in Q-band through the synthesis and optimization of a peculiar small shaped ILA (28 mm/spl times/28 mm/spl times/15 mm) fed by an aperture-coupled microstrip patch antenna.

A complete procedure for the design and optimization of arbitrarily shaped integrated lens antennas

In this paper, the capability of ultra-wide-band (UWB) sensor arrays for tomographic radar of electrically large objects is presented. The major concern when imaging is extended to real objects is to achieve a correct reconstruction of the object shape and its electric properties. A general framework based on a UWB bifocusing operator (UWB-BF) with good tomographic imaging capabilities is presented. This general approach provides a comprehensive understanding of the basic tradeoffs with regard to sensing geometry and image quality parameters. Through numerical simulations and measurements applied to canonical as well as to complex objects, basic design criteria are assessed and the potential of UWB tomographic radar imaging is presented.

UWB Tomographic Radar Imaging of Penetrable and Impenetrable Objects

In this paper, the capability of ultra-wide-band (UWB) sensor arrays for tomographic radar of electrically large objects is presented. The major concern when imaging is extended to real objects is to achieve a correct reconstruction of the object shape and its electric properties. A general framework based on a UWB bifocusing operator (UWB-BF) with good tomographic imaging capabilities is presented. This general approach provides a comprehensive under- standing of the basic tradeoffs with regard to sensing geometry and image quality parameters. Through numerical simulations and measurements applied to canonical as well as to complex objects, basic design criteria are assessed and the potential of UWB tomographic radar imaging is presented.

UWB Tomographic Radar Imaging of Penetrable and Impenetrable Objects Ultrawide-band tomography, producing images that show slices of objects, is less harmful than x-rays and can provide useful, high resolution images.

An apparatus, system, and method are disclosed for wireless communications. A planar antenna element is disposed on a surface of a substrate. The planar antenna element comprises an electrically conductive material and has a circular polarization. The substrate comprises a dielectric material. The planar antenna element may be arranged in a planar antenna array as a feed for a reflector antenna or as an aperture array. The planar antenna element may comprise a slot patch antenna element with a slot in the electrically conductive material of the planar antenna element circumscribing the planar antenna element. The slot exposes the dielectric material of the substrate. A ground plane may be disposed on the surface of the substrate. The ground plane comprises an electrically conductive material. The slot may be disposed between the ground plane and the patch antenna element.

Planar array feed for satellite communications

The off-axis performances at 77 GHz of multilayered half Maxwell fish-eye (HMFE) lenses fed by an open-ended waveguide is describes. When moving the feed with respect to (w.r.t.) the lens, it is shown that at least 40deg of scanning can be achieved. Several off-axis configurations of the lens antenna are investigated and compared using a full-wave electromagnetic software. The directivity, far field pattern and scan angle of the lens antenna are reported for a rectilinear and angular off-axis displacement of the feed and also for various distances between the feed and the lens. It is also shown that a three-shell lens is good enough to achieve a wide scan angle. Finally, off-axis measurements done with a three-shell 6.15 lambda0-diameter HMFE lens antenna are compared to computed results to validate the simulations

Off-Axis Performances of Half Maxwell Fish-Eye Lens Antennas at 77 GHz

The invention consists of an antenna array, for the reception of two frequency bands, comprising two pairs of radiating elements and an network for excitation of these elements for the reception of one of the bands The radiating elements are positioned so as to free the center of the array to allow colocalized reception of the other band The excitation network comprises hybrid elements so as to introduce a certain phase shift between the radiating elements allowing a dual circular polarization  This network must comply with two constraints:The phase shift introduced between the hybrids must be equal to the phase shift of the hybrid modulo 2kττ, k integer, and the length of the line L1 placed between the first hybrid H1 and the first patch PA1 is such that it introduces a phase shift equal to π modulo 2kττ, k integer

Antenna arrays with dual circular polarization

This work presents a low-cost, multi-beam antenna system, using a dielectric homogeneous lens as a focusing system. First, the design methodology of the antenna system, combining a homogeneous lens and its primary source, is described. Then, aberration phenomena generated by the lens are characterized. Finally, the primary source, used to correct these aberrations, is briefly described and measurement results of the global antenna system are presented.

Cost effective antenna for LEO-satellites communication system using a homogeneous lens

Two dual band K/Ka polarizers have been designed, taking into account dimensions constraints for easiness of manufacturing and low cost production. The short polarizer (1.9/spl lambda/) presents very good performances, S11<-30 dB and axial ratio better than -0.5 dB in Rx and Tx frequency bands, for classical K/Ka frequency. The second dual band polarizer which is also very wide band in each Tx and Rx frequency bands; has good performances over the dual and wide bands (AR better than -1.74 dB). The specifications have still reached after the yield analysis on all dimensions. These polarizers have the particularity to be very short versus the current ones on the market, with still good performances and manufacturability easiness, which made them very attractive for consumer two way systems by satellite. A prototype is on-going in being manufactured to verify the performances.

Design and optimization of dual and wide band polarizer for low cost Ka band applications

This paper describes different measurements schemes for UWB antenna characterization in frequency domain as well as in time domain The antenna measurements are well known in frequency domain, but the UWB technology introduces new requirements, especially in the time domain and then different measurement methods are necessaries The time domain characteristics could be obtained through direct method -in the time domain- or through indirect method with link synthesis ?in the frequency domain The specific schemes applied for the direct and indirect method are exposed The UWB antennas considered are printed dipoles antenna covering the full band of 31 GHz to 106 GHz The simulation and measurement results performed by direct and indirect methods are compared and the antenna behavior is then explained and exposed

Evaluation and Characterization of an UWB Antenna in Time and Frequency Domains

The invention proposes a primary feed providing an asymmetrical illumination compatible with an elliptical reflector and having a small space requirement. The invention uses a short rod to modify the radiation of an open waveguide section. The invention is an antenna comprising a radiating feed made up of a waveguide 1, one end of the waveguide forming a radiating aperture. The end forming the radiating aperture is fitted with a rod made of dielectric material, said rod being partly inserted 2, 3 in the waveguide 1. The rod is extended outside the waveguide over a length L less than twice the guided wavelength and the section of the rod develops outside the waveguide differently in each of the planes.

Philippe Chambelin

Papers

Antenna arrays with dual circular polarization

Cost effective antenna for LEO-satellites communication system using a homogeneous lens

Design and optimization of dual and wide band polarizer for low cost Ka band applications

Evaluation and Characterization of an UWB Antenna in Time and Frequency Domains

Radiating aperture waveguide feed antenna