Abstract: This invention relates to reducing the complexity and cost of antenna arrays and is more specifically concerned with reducing the complexity of an antenna apparatus (10). It provides an antenna array (62) made up of a vertical stack of horizontal linear structures (74) each having several groups of neighboring array antenna elements (78), the groups (74) having variable numbers of the antenna elements (78) each connected to a transmit/receive module (66). The advantage of this configuration is that less communication modules (66), such as transmit/receive modules, are required to operate the antenna array (62), reducing the weight, power consumption and cost of an antenna apparatus (10) incorporating such an antenna array (62) without significantly limiting the capability and/or performance of a system compared to a conventional solution.

Abstract: Described herein is a method and apparatus for improving high range resolution of a radar system. The method comprises phase shifting a radar pulse to be transmitted at substantially the radar transmission frequency and phase shifting the received radar pulse at substantially the radar transmission frequency. The phase shifting is implemented using a monolithic microwave integrated circuit (MMIC) (42) driven by a digital circuit (44) to provide a phase profile which is applied to radar pulse (52) produced by a radar pulse generator (54) and which is also applied to a received radar pulse (60). A master clock and synchronizer (72) provides clock signals for an analogue to digital converter (ADC) (68), the generator (54) and the digital circuit (44) so that the MMIC (42) is clocked at a frequency which is directly harmonically related to the ADC (68). This avoids spurious beat frequencies which could interfere with a wanted radar signal.

Abstract: A method and apparatus are provided for determining whether a signal received the main channel (2) of an antenna (1) was incident on the antenna (1) in a direction corresponding to a high gain main lobe. A sidelobe suppression signal is generated from signals received from a other channels at least some of which are derived from elements where output generates the main channel, the signal being categorized as originating from a direction corresponding to the high gain main lobe of the main channel by comparing the value of the signal received on the main channel with that of sidelobe suppression signal.

Abstract: Electrical apparatus comprises a number of modules (4) supplied with eletrical power by ducts (6) which convey cooling fluid between adjacent modules (4).