S. Ranvier

Measurement setup and associated calibration methodology for 3D radiation pattern of probe-fed millimeter-wave antennas

In this paper, we present a radiation pattern measurement setup for probe-fed millimeter-wave antennas and the associated calibration procedure. Compared to other existing facilities, our setup has one major innovation: it is composed of two rotating arms allowing measuring the radiated field of a probe-fed antenna over the quasi-3D sphere. The calibration challenges and issues encountered at 60 GHz are thoroughly described. We especially detail a dedicated calibration procedure to improve the accuracy of the measurements. To illustrate our methodology, the 3D radiation pattern measurement of a monopole-type antenna etched over a glass substrate is presented. Experimental results are compared versus simulation results.

Poly-SiGe-based MEMS Xylophone Bar Magnetometer

This paper presents the design, fabrication and preliminary characterization of highly sensitive MEMS-based Xylophone Bar Magnetometers (XBMs) realized in imecs poly-SiGe MEMS technology. Key for our Lorentz force driven capacitively sensed resonant sensor are the combination of reasonably high Q-factor and conductivity of imecs poly-SiGe, our optimized multiphysics sensor design targeting the maximization of the Q-factor in a wide temperature range as well as our proprietary monolithic above-CMOS integration and packaging schemes. Prototypes 3-axis devices were fabricated and characterized. We present optical vibrometer and electrical S-parameter measurements of XBMs performed in vacuum with a reference magnet at increasing sensor separation. The optical oscillation amplitude is well correlated with the magnetic field amplitude. The electrical 2-port measurements, 1st port as Lorentz force actuator and 2nd port as capacitive sensor, also reproduces the designed magnetic field dependence. This opens the way towards the on-chip integration of small footprint extremely sensitive magnetometers.

Influence of multiphysics couplings on the performance of a MEMS magnetometer

In this paper, several physical phenomena that are usually not taken into account in MEMS simulations are considered for the simulation of a MEMS xylophone bar magnetometer. These phenomena are the temperature dependency of the material properties, the strong coupling between various fields of physics (thermal, electric and mechanical) and the stress produced by the change of temperature inside the structure. It is shown that the temperature dependency of the material properties has a relatively small influence whereas the pre-stress has a significant one. Because of the pre-stressed state, the deformation of the bar at the fundamental frequency is not a typical first mode vibration but it exhibits additional waves between the linkages, where the bar is stressed, which significantly decrease the amplitude of the deflection.

Instrumentation of the Belgian RAdio Meteor Stations (BRAMS)

BRAMS (Belgian RAdio Meteor Stations) is a network of radio receiving stations using forward scatter techniques to study the meteoroid population. The main goals are to compute meteoroid flux rates and mass indexes, determine individual meteor trajectories and orbital parameters of meteoroids, and to analyse meteor profiles in order to retrieve physical parameters of the meteoroids. For that purpose, a dedicated beacon is used together with 26 single-antenna receiving stations spread over Belgium, one dual antenna station and one interferometer. The instrumentation of this network is described in this paper.

Use of a Langmuir Probe Instrument on Board a Pico-Satellite

The sweeping Langmuir probe instrument is a part of the payload of PICo-satellite for atmospheric and space science observations (PICASSO), an ESA in-orbit demonstrator. It includes four thin cylindrical probes whose electrical potential is swept to measure both plasma density and electron temperature together with the spacecraft (S/C) potential. PICASSO is a triple unit CubeSat of dimensions

BRAMS: The Belgian RAdio Meteor Stations

340.5~\text {mm} \times 100~\text {mm} \times 100

Mutual Coupling Reduction for Patch Antenna Array

mm. The orbit is expected to be a high inclination low-earth orbit. The main issue implied by the use of a pico-satellite platform for a Langmuir probe instrument is the limited conducting area of the S/C, which leads to S/C charging and drift of the instrument’s electrical ground during the measurement. A specific measurement technique that includes the simultaneous measurement of the potential and current of different probes has been developed to retrieve consistent current–voltage characteristics that can be used to estimate the plasma parameters mentioned above.

Calibration methodology for a 3D radiation pattern set‐up of probe‐fed millimeter‐wave antennas

BRAMS (Belgian RAdio Meteor Stations) is a new facility currently developed in Belgium to detect and study meteors with radio forward scattering techniques. The transmitter is a dedicated beacon and 25 receiving stations (including one interferometer) are spread all over Belgium. The characteristics of BRAMS and the scientific goals of the project will be discussed. Preliminary results for the automatic detection and counting of meteor echoes will be presented as well as initial results obtained with the interferometer. The methods planned to calculate meteoroid flux densities and trajectories of individual meteoroids will be discussed.