Abstract: A mode S Interrogation Side Lobe Suppression System (ISLS) for an electronically scanned interrogator is described. One aspect introduces the 90° phase offset between the main and control beams thereby enabling the full power capability of the TRU to be effectively utilized and the effective beamwidth in Mode S to be sharply defined. The system allows the transmission of the simultaneous ISLS pulse of a Mode S all-call interrogation to be transmitted using the same array as is used by the main beam.

Abstract: An RF signal to be carried by an optical link is modulated onto two optical beams. The modulators are tuned differently so that the distortion products carried on one beam are relatively larger compared to the fundamental compared with other beam. One of the beams is optically upconverted by the appropriate Brillouin shift frequency and the two beams counter-propagated through an optical waveguide in order to create a Brillouin grating. The grating acts to separate the distortion products from the fundamental so as to provide at an output of the link a signal in which the distortion products are insignificant is not absent.

Abstract: A laser system having an optical ring resonator, a beam splitter that directs a first beam travelling in a first direction around the ring resonator, out of the resonator towards a reflector that reflects the first beam back into the resonator to travel in an opposite direction around the optical ring resonator that is in the same direction as a second beam travelling around the optical ring resonator; and a beam modifier configured and adapted to modify a spatial distribution of phase across an aperture of the first beam such as to cause it to become more similar or substantially match that of a spatial distribution of phase across an aperture of the second beam.

Abstract: An RF signal to be carried by an optical link is modulated onto two optical beams. The modulators are tuned differently so that the distortion products carried on one beam are relatively larger compared to the fundamental compared with other beam. One of the beams is optically upconverted by the appropriate Brillouin shift frequency and the two beams counter-propagated through an optical waveguide in order to create a Brillouin grating. The grating acts to separate the distortion products from the fundamental so as to provide at an output of the link a signal in which the distortion products are insignificant is not absent.

Abstract: There is described a dielectric polariser for a bicone antenna. The polariser can include radiating vanes that are spaced circumferentially around an aperture of the bicone antenna. The vanes are orientated at 45° to the polarised waves propagated from the antenna in order to circularly polarise the linearly polarised waves. The polariser can be configured for manufacture using a 3D printing process. Surfaces of a central hub of the polariser can be metallised to provide the radiating surfaces of the antenna. This removes the need to use separate antenna elements. Alternative arrangements of 3D printed dielectric polariser are disclosed for use with antenna horns.

Abstract: A system and method of down converting microwave (RF) signals into lower frequencies are disclosed, such that associated electronics can more precisely analyse the signals. Exemplary embodiment, can be applied to multiple RF bands by using several optical wavelengths.

Abstract: A technique for making high performance low noise amplifiers, low cost high performance RF, microwave circuits and other devices by using a minimum of costly high performance semiconductors is described. By combining a single discrete portion of an expensive semiconductor with a less expensive GaAs carrier, MMIC devices with improved performance over their discrete counterparts are achieved.

Abstract: Modern military aircraft are prime targets for surface to air and air to air RF guided missiles. Modern missile systems in particular are difficult to counter and have an array of Electronic Protection Measures at their disposal. Expendable Active Decoys provide effective protection for fast jet platforms by creating a realistic false target that seduces the missile away from the protected platform. They can be fitted to almost all military platforms as they are expended from standard chaff and flare dispensers. Simple repeater devices have been produced in the past but they lack the sophistication to defeat modern threats. Digital RF Memory based jammers have the necessary capability but have always been too large due to their complexity. A system architecture, design features and technologies are disclosed to reduce the size of a Digital RF Memory 12 based jammer to fit within a volume 0.5 l.

Abstract: A mode S Interrogation Side Lobe Suppression System (ISLS) for an electronically scanned interrogator is described. One aspect introduces the 90° phase offset between the main and control beams thereby enabling the full power capability of the TRU to be effectively utilized and the effective beamwidth in Mode S to be sharply defined. The system allows the transmission of the simultaneous ISLS pulse of a Mode S all-call interrogation to be transmitted using the same array as is used by the main beam.

Abstract: A system and method of down converting microwave (RF) signals into lower frequencies are disclosed, such that associated electronics can more precisely analyse the signals. Exemplary embodiment, can be applied to multiple RF bands by using several optical wavelengths.

Abstract: A system and method for calibrating an imaging system includes a shutter that is moveable in to the optical path of the imaging system to generate an image of the shutter surface, which is flat and uniform. The shutter can be moved in and out of the optical path between first and second positions. The shutter is heated while in the second position and then returned to the first position. Data sets generated at two different temperatures enable the image generated by the imaging system in normal use to be to be adjusted for responsivity and variation in DC offset of the specific pixel array.

Abstract: A camera for polarimetric, multispectral imaging is described. Such cameras are used in photonics, computational imaging and multispectral imaging in which both multispectral and polarimetric sensing modalities are used simultaneously for detection, recognition and identification. The camera enables multiple spectral images to be recorded simultaneously using polarizing beamsplitters and mirrors to divide the image according polarimetric and spectral bands. These multiple, polarized images are recorded on a single focal plane array (FPA) simultaneously. An image processor allows for the resolution of the subsequent image to be improved.

Abstract: A de-icing system for a hemispherical protective housing mounted on an aircraft structure is described. The system can include a series of piezo-electric devices mounted at the boundary of the housing. The piezo-electric devices generate ultrasonic frequencies and resonance of the protective housing is induced. One of the piezo-electric devices senses the frequency generated in the protective housing and acts as part of a feedback loop to maintain structural resonance of the protective housing. The structural resonance of the protective housing prevents the build-up of ice. Additionally, higher power resonances can be generated to remove ice already built up on the protective housing. The system also enables detection of ice build-up on the protective housing by monitoring any change in the frequency required to maintain structural resonance of the protective housing.

Abstract: A wideband digital phase meter and phase detection method are disclosed. The device measures a phase difference between 2 signals and is suitable for integration into a single MMIC. The input signals are compared digitally by using two EXOR gates and integrated over a phase comparison period. The resultant analogue signals are digitised using an Analogue to Digital convertor. Additionally, 2×D-Type registers are used to resolve the (0° to 180°) or (180° to 360°) ambiguity of the EXOR phase detector.

Abstract: A power amplifier is described that includes a balanced amplifier arrangement having an input quadrant coupler and output quadrant coupler and two amplifiers, which may include or consist of single transistors, there between. The power amplifier also can provide a signal to an isolated port of the output coupler in order to provide impedance matching. This arrangement dispenses with the need for transistor matching networks at the output of the two amplifiers, which in turn enables the power amplifier to be operable over a wider frequency range as compared with a Doherty power amplifier.

Abstract: An Infra Red detector system and method is disclosed that implements a digital coordinate generator onto a 2D focal plane array infrared detector. The method used in this form of the invention by the IR detector system, generates X-Y coordinate data for pixels containing detected target data. Advantageously, it reduces subsequent signal post processing required to generate the same data using numerical processing techniques in software and the latency that this introduces.

Abstract: A technique for making high performance low noise amplifiers, low cost high performance RF, microwave circuits and other devices by using a minimum of costly high performance semiconductors is described. By combining a single discrete portion of an expensive semiconductor with a less expensive GaAs carrier, MMIC devices with improved performance over their discrete counterparts are achieved.

Abstract: A tow cable for a decoy on a fast jet aircraft is described. The tow cable has a composite structure with a high friction fibre outer containment braiding, and low friction fibre internal strength members. Additional to these internal fibres may be electrical conductors and optical fibres. The whole composite providing a tow cable with high towing endurance and reliable in-flight performance, for flight profiles including high performance manoeuvres and in-flight refuelling.

Abstract: An infrared detector system is described which includes a detector diode array 3 and a non volatile memory 1. The non volatile memory 1 can use CMOS Silicon Fuse technology which can be polysilicon devices that are programmed using voltage-current-time profiles suitable for the silicon process technology, such that when applied will cause the polysilicon element to heat up rapidly and melt. This results in the fuse element going open circuit, just like blowing a known fuse. The fuse can act as a logic element that has a one time, user programmable and permanent logic state. An array of such memory cells is can be mapped to a sub pixel diode detector array.

Abstract: A large format array is described having a series of smaller arrays daisy chained together to form the larger array. The smaller arrays are mounted on a base plate that may be of a non planar configuration. The daisy chaining together of the smaller arrays enables a smaller number of connections to be made to the external interface via connections.