van R Robert Dijk

Millimeter-wave antenna measurement

A novel approach is presented to accurately measure the scattering parameters as well as the radiation pattern of planar antennas that operate in the millimeter-wave frequency band. To avoid interconnection problems, RF probes have been used to connect to the antenna. These RF probes are normally used for the characterisation of devices on a semiconductor wafer. Here, they are used to characterise antennas that can be realised in any planar manufacturing technology. A completely planar transition is designed to transform the coplanar waveguide transmission line that is required by the RF probe to a microstrip line. It is shown that this transition can be de-embedded from the measurements. Moreover, a measurement setup has been built for the measurement of the far-field radiation pattern of millimeter-wave antennas and antenna arrays. This setup allows to connect the antenna under test with an RF probe and can measure the radiation pattern in the whole upper hemisphere.

Photonic chip for steering a four element phased array antenna

A polarization independent photonic integrated circuit for phase steering of a four element phased array antenna has been fabricated on InP. The chip is extremely small and suitable for packaging.

Modelling and design of a travelling-wave electro-optic modulator on InP

Based on a rigorous vectorial analysis, a fast travelling-wave Mach–Zehnder modulator is modelled and designed. The cross-section of the semiconductor layer stack and the lossy electrodes are carefully modelled using the method of lines in order to investigate propagation characteristics, velocity and losses. This yields an accurate microwave and optical field distribution to explain the behaviour of the component. In order to enhance the modulation efficiency, design curves are derived and the cross-sectional dimensions for minimum microwave loss are determined. The loss of the optimized modulator agrees very well with small-signal measurements up to 40 GHz and HFSS simulations. The layerstack of the fabricated device is suitable for integration with InP multi-wavelength lasers.