Abstract: A structure which exhibits magnetic properties when it receives electromagnetic radiation is formed from an array of capacitive elements each of which is smaller, and preferably much smaller, than the wavelength of the radiation. Each capacitive element has a low resistance conducting path associated with it and is such that a magnetic component of the received electromagnetic radiation induces an electrical current to flow around the path and through the associated element. The creation of internal magnetic fields generated by the flow of the induced electrical current gives rise to the structure's magnetic properties.

Abstract: The performance of a microwave antenna is improved by incorporating a fine wire dielectric material which has a dielectric constant ∈ of less than unity at microwave frequencies. The effect of the dielectric material is to refract microwaves so that the antenna appears to have a larger aperture than that of its physical size. Furthermore, by selecting the transmission cut off frequency of the dielectric material, two antenna elements which are intended to operate within different frequency bands can be mounted one behind the other.

Abstract: A transistor having a support substrate of semiconductor material and continuous elongate electrodes--a source electrode a drain electrode and a gate electrode. Gain improvement is achieved by dividing the structure into active and passive sites and by providing inductive coupling to supply power feedback to the gate electrode and thereby to sustain and enhance guided wave propagation. At each active site, protrusions extend from the source electrode, and protrusions extend from the drain electrode. The parasitic capacitance at each passive site is thus minimized. The source and drain protrusions are connected by channels in the underlying semiconductor substrate and the conductivity of these channels controlled by gate operation. The drain electrode has a meander configuration to provide inductive coupling to the gate electrode and balance the waves on drain and gate. To reduce resistive losses, the gate electrode is of larger cross-section at passive sites.