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In this paper, we describe the design of an electrically large anechoic chamber for usage on millimetre-wave bands. Ansys Savant sotware was used to perform a simulation of the chamber, using physical optics coupled with uniform theory of diffraction (PO/UTD). Moreover, a method based on an open waveguide probe is described in this paper to obtain the electrical properties of the RF absorbers at millimetre-wave frequencies. Two different source antennas were simulated in this work and the corresponding quiet zones predicted. The largest quiet zone was 30 &times, 30 &times, 50 m m , for a chamber size of 1 . 2 &times, 0 . 6 &times, 0 . 6 m .

The authors present the design of a tunable 433 MHz antenna that is tailored for wearable wireless sensor applications. This study first presents a detailed analysis of the measured impedance characteristics of a chosen antenna under test (AUT) in varying proximity to a human test subject. Instead of limiting the analysis to the head and hand only, this analysis measures the AUT impedance at varying distances from 11 different body positions. A novel antenna equivalent circuit model is then developed that enables both the free-space and total on-body AUT impedance variation to be rapidly computed using a circuit simulator instead of the requirement for computationally intensive finite-element methods for example. The design and characterisation of a tunable matching network that enables AUT impedance matching for 11 different positions on the human body is then outlined. Finally, a fully-autonomous 433 MHz tunable antenna is demonstrated. The antenna occupies a small printed circuit board area of 51 × 28 mm and is printed on standard FR-4 material with the tuner completely integrated into the antenna itself. Prototype measurements show an improvement of 3.9 dB in power delivery to the antenna for a load voltage standing wave ratio of 17:1, with a maximum matching loss of 0.84 dB and S 11 (−10 dB) ≥ 18 MHz for all load conditions.

International audience; In this paper, a 5G MIMO mobile phone prototype including four antennas working in the 10-13.2 GHz band is designed. The objective of the study is to evaluate the negative impact due to the user's hand in frequencies higher than 10 GHz. A 3D spherical near-field scanner with fixed Antenna Under Test (AUT) is leveraged in order to measure a 3D radiation pattern with a real human hand impact. S-parameters, radiation pattern and efficiency are presented. First results show that radiation pattern and efficiency are strongly impacted by the hand. This effect has to be carefully considered for millimeter Wave handheld terminal design.

International audience; We describe the design, fabrication and measurements of an axisymmetric dielectric lens, featuring a sectorial radiation pattern at 77 GHz. It will be used as the primary feed of a lens-based compact antenna test range (CATR). Due to symmetry of revolution, the sectorial lens profile can be designed in one dimension by using phase only control. The phase variation is echoed on the lens depth. The resulting stepped lens is simulated using France Telecom Orange Labs SRSRD software (¿in-house¿ software developed for dielectric axisymmetric radiating structures) and measured in an anechoic chamber at 77 GHz. Two lenses were fabricated with different materials: PVC and polyurethane, respectively. Good agreements were obtained between simulations and measurements. Less than 0.2 dB ripple in the central beam are obtained for the polyurethane lens although relatively high secondary lobes occur at 11°. Comparisons between the near field of a CATR illuminated by a small horn providing a uniform amplitude taper and the sectorial lens are conducted using numerical simulations. Results show that on-axis oscillations are reduced from 6 to 1 dB with the sectorial lens.

International audience; A designed microstrip grid array antenna at 94 GHz in a low-temperature co-fired ceramic (LTCC) technology was fabricated and measured. The designed and measured results are in good agreement. They show a 10-dB impedance bandwidth of 5.12 GHz from 90 GHz to 95.12 GHz (or 5.45% at 94 GHz), a maximal peak realized of 17.1 dBi with a 3-dB gain bandwidth of 5.5 GHz from 92.0 GHz to 97.5 GHz (or 5.85% at 94 GHz). These good performances make the microstrip grid array antenna a suitable candidate for 94-GHz applications.

A wideband, wide-scan prototype phased array of connected dipoles has been manufactured and tested from 3 to 5 GHz. The array comprises 7 × 7 elements, each fed by a loop-shaped transformer to avoid common-mode resonances. Such resonances typically affect this type of arrays, with consequent degradation of the polarization performance. The common-mode rejection implemented by the loop transformers allows to maintain the cross-polarization levels to values lower than -10 dBs over a 30% relative bandwidth, for elevation angle up to 45° in all azimuth planes. The array exhibits a measured voltage standing-wave ratio (VSWR) lower than 2.5 from 3 to 5 GHz for broadside radiation. © 2012 IEEE.

TOPICA (Torino Polytechnic Ion Cyclotron Antenna) code is an innovative tool for the 3D/1D simulation of Ion Cyclotron Radio Frequency (ICRF) antennas, i.e. accounting for realistic 3D antenna geometries and for accurate 1D plasma models. The tool calculates the antenna input parameters at the feeding ports given the exact port excitation. Moreover, it calculates the current distribution and electric field maps wherever specified. The recent upgraded parallelized version of TOPICA permits the analysis of large and complex antenna structures in a reasonable simulation time (less than one day). A detailed analysis of the performances of two ITER ICRF antenna geometries has been carried out, underlining the strong dependence and the asymmetries of the antenna input parameters due to plasma conditions. An optimization of the antenna dimensions has also been accomplished. Electric current distribution on conductors in the vacuum region and electric field distribution in the vacuum region and at the interface with plasma edge have been calculated as well. The analysis shows the strong capabilities of the parallelized TOPICA code as a predictive tool and its usefulness to ICRF antennas final design.

The design of a multifrequency integrated probe performing phaseless near-field measurements is presented. Two X-band rectangular waveguides directly connected to a microstrip circuit are used for making the near-field scanning which provides the necessary amplitude information. An interferometric algorithm is applied in conjunction with a minimization procedure to obtain the unknown near-field phase. A prototype of the probe has been realized and successfully tested on a standard X-band pyramidal horn.

A simple and effective method to avoid the truncation error in antenna near-field measurements is presented. The method can be applied to planar or cylindrical near-field setups, whenever it is possible to vary the distance between the antenna under test and the probe during the scanning procedure.

A number of interferometric methods applied to array diagnosis are investigated. Numerical and experimental results show that interferometric algorithms which are not affected by spectrum overlapping problems allow a more accurate evaluation of the excitation coefficients.

An integrated probe performing phaseless near-field measurements on a polar surface is presented. The unknown near-field phase is computed by an interferometric technique used in conjunction with the minimisation of a suitable functional. A microstrip patch antenna for synthetic aperture radar (SAR) applications is considered to validate the method.

The quiet-zone field test results of a submillimetre-wave compact antenna test range (CATR) based on a 60 cm diameter hologram are presented. The instrumentation setup based on a dedicated millimetre-wave vector network analyser is also briefly described. The presented test results at 310 GHz show the potential of the hologram CATR for submillimetre-wave antenna testing.

The circular disc monopole (CDM) antenna has been reported to yield wide-impedance bandwidth. Experiments have been carried out on a CDM that has twice the diameter of the reported disc with similar results. New configurations are proposed such as elliptical (with different ellipticity ratios), square, rectangular, and hexagonal disc monopole antennas. A simple formula is proposed to predict the frequency corresponding to the lower edge of the bandwidth for each of these configurations. The elliptical disc monopole (EDM) with ellipticity ratio of 1.1 yields the maximum bandwidth from 1.21 GHz to more than 13 GHz for voltage standing wave ratio (VSWR), IEEE