Anthony Bellion

Feasibility of indoor spherical near field antenna measurement facility in VHF range

This paper details a study on the feasibility of an indoor antenna spherical near field measurement system in VHF range. Any constraints in terms of manufacturing or building are taken into account. Only electromagnetic and mechanical aspects required for antenna characterization are analyzed in order to appreciate such a measurement facility. After introduction on measurement needs in low VHF range, authors focus on ferrite performances analyses. Then a complete reflectivity analysis is done for each constituting elements of the facility. Finally is provided a global budget error to appreciate the feasibility of the antenna measurement system and prospects axes are discussed.

Wideband dual-polarized magneto-electric miniaturization using capacitive loading

In this paper, an original method to reduce the height of a dual-polarized unidirectional wideband antenna based on two crossed magneto-electric dipoles is proposed. The miniaturization technique consists in adding a capacitive load between vertical plates. The height of the radiating element is reduced to 0.1λ0, where λ0 is the wavelength at the lowest operation frequency for a Standing Wave Ratio (SWR) <2.5, which corresponds to a reduction factor of 37.5%. The measured input impedance bandwidth is 64% from 1.6 GHz to 3.1 GHz with a SWR <2.5.

Frequency reconfigurable wideband compact dual-polarized magneto-electric dipole

In this paper, a novel wideband frequency reconfigurable compact dual-polarized magneto-electric dipole is presented. The antenna has two operation modes and cover an ultra-wideband operation frequency from 1.5 to 2.8 GHz and from 2.5 to 4.6 GHz with a Standing Wave Ratio (SWR) <3. RF PIN diodes are placed on the antenna structure and used as switches to select different operation modes. Moreover, in the lower operation band adding a capacitive loading allows to miniaturize the antenna height to 0.1λ.

Detailed uncertainty analysis of the electrically small antenna efficiency measurement

Radiation efficiency is a key performance indicator for multi-standards frequency agile electrically small antennas (ESA) that are mounted on wireless IoT sensors. One of the techniques to estimate it, consists to integrate, over all the angular directions, the gain measured in the far field condition. The gain-comparison method is usually implemented in the CEA LETI test bench; which requires an accurate knowledge of the standard horn gain. The introduction of a new RF-optical link to remove coaxial cable perturbation on ESA radiation, in our test bench has raised the opportunity to proceed to an error budget analysis. This paper delivers the main results of this study where the impact of several parameters such as the optical fiber movement, the horn positioning, the received power level, and the chamber imperfection have been evaluated. The three antennas method (one Vivaldi and two TEM standard horns) is carried on to estimate the complex transfer function of the three antennas. The overall goal is to estimate the detailed uncertainty analysis of the ESA efficiency measurement over a large frequency band. This work aims to identify the most impacting effects on uncertainty and to initiate the discussion with the AMTA community how to decrease them.

Comparison of antenna measurement results in disturbed environment using a VHF spherical near field system

This paper presents parts of investigations done in a VHF spherical Near-Field system in order to propose appropriate measurement procedure. First is briefly presented the mono-probe near field system and measurement challenges due to low frequencies. Then is presented the Antenna Under Test (AUT), the antenna pattern comparison approach and the measurement configurations. Finally, several measurement results using two scans configurations are compared to reference simulation result in order to find the most appropriate way of measurement suited to the measurement facility for the large wavelength considered.