Abstract: A freestanding frequency selective surface (FSS) is provided which comprises at least one shorted resonance aperture element (12). The shorted resonance aperture element provides a sensitivity to polarization. The shorted resonance aperture element may comprise at least one short, which may enable the FSS to be freestanding. The invention further provides an FSS device comprising at least one array of the freestanding frequency selective surfaces, and a method of forming the freestanding frequency selective surfaces.

Abstract: An integrated circuit (IC) substrate (32) comprising a germanium layer (26), an aluminium oxide layer (22), and an interfacial layer (28) provided on the germanium layer between the germanium layer and the aluminium oxide layer, which interfacial layer provides control of electrical properties at an interface between the germanium layer and the interfacial layer. The electrical properties may comprise charge carrier trap density, and the interfacial layer may provide control of the charge carrier trap density to minimise the trap density. The interfacial layer is used to ensure an intimate, high-quality germanium layer—interfacial layer interface. A method manufacturing an IC substrate is also provided, along with a gallium arsenide circuit integrated in a system-on-chip (SOC) comprising an IC substrate, and a germanium electronic circuit in combination with a gallium arsenide circuit, integrated in a system-on-chip—(SOC), comprising an IC substrate.

Abstract: A freestanding frequency selective surface (FSS) is provided which comprises at least one shorted resonance aperture element (12). The shorted resonance aperture element provides a sensitivity to polarisation. The shorted resonance aperture element may comprise at least one short, which may enable the FSS to be freestanding. The invention further provides an FSS device comprising at least one array of the freestanding frequency selective surfaces, and a method of forming the freestanding frequency selective surfaces.

Abstract: A passive microvalve comprises a substrate having a first aperture. An upper plate is mounted on the substrate and has a second aperture opening into a space defined between the substrate and the upper plate. A closure member is mounted in the space and is movable between a first position in which it allows fluid flow between the first and second apertures and a second position in which it closes the second aperture.