Abstract: An antenna (10) suitable for a mobile telephone or other such communication device has a transmission element (21) to transmit and receive an electromagnetic radiation pattern. The transmission element (21) is supported on a layer or layers (25) of dielectric material, control over the orientation of a radiation pattern to be transmitted or received being maintained electronically. The transmission element (21) includes at least one loop and is often in a spiral configuration. Switches (23, 24) in the form of a microelectromechanical switch or a PIN diode, capable of short or open circuiting the element (21), allow the orientation of the radiation pattern to be altered. The dielectric constant of the dielectric material (25) is variable, again affecting the orientation.

Abstract: An integrated high speed driver/modulator assembly includes a driver amplifier assembly having a specified input impedance, such as 50 ohms. The driver/modulator assembly also includes an optical modulator having a modulator transmission line. The impedance of the modulator transmission line is less than the specified input impedance, which results in a reduced V&pgr; for the optical modulator. The reduction in V&pgr; enables the driver/modulator assembly to more effectively support OC-768 and higher data rates of at least 40 Gb/s.

Abstract: An optical modulator electrode structure includes a drive signal electrode having a coplanar section that is coplanar with at least one ground electrode. The drive signal electrode also includes a fin section and a wall section connecting the fin section to the coplanar section. The fin section overlaps at least a portion of a ground electrode and dielectric material is located between the fin section and the underlying ground electrode. The electrode structure transmits electromagnetic energy in two modes: a coplanar waveguide mode and a microstrip mode. The electrodes may be formed on an optical waveguide substrate, such as lithium niobate, or on a dielectric layer overlying the optical waveguide substrate. In a typical optical modulator application, the electrode structure should (or is believed to) exhibit less conductor losses and facilitates better velocity matching.

Abstract: An integrated high speed driver/modulator assembly includes a driver amplifier assembly having a specified input impedance, such as 50 ohms. The driver/modulator assembly also includes an optical modulator having a modulator transmission line. The impedance of the modulator transmission line is less than the specified input impedance, which results in a reduced V&pgr; for the optical modulator. The reduction in V&pgr; enables the driver/modulator assembly to more effectively support OC-768 and higher data rates of at least 40 Gb/s.

Abstract: In a non-destructive method for the detection of surface cracks in metals, an eddy current is induced in the surface region of a workpiece under test, at a frequency sufficiently high to generate an alternating magnetic field solely in the skin region of the workpiece. That alternating surface magnetic field is interrogated by means of a relatively small electro-magnetic induction sensor, having regard to the overall area of the induced magnetic field. The sensor provides a voltage output which is analysed, preferably in real time, to yield an indication sensor. Also described is a probe for performing such a method.