Abstract: A phase conjugate circuit is disclosed for deriving phase conjugation information from a main input signal of a given frequency comprising: an input receiving a reference input signal; at least one phase locked loop circuit comprising an oscillator having a main output signal, an input receiving a PLL input signal, an input receiving a feedback signal from the oscillator and at least one phase detecting means, wherein the phase detection means detects any phase difference between the PLL input is signal and the feedback signal and provides a phase control signal to the oscillator. Ion one embodiment, the main input signal is mixed with the main out put signal to provide the feedback signal and the reference signal is the PLL input signal. In an alternative embodiment, the reference signal is mixed with the main output signal to produce the feedback signal and the main input signal is the PLL input signal.

Abstract: A class E power amplifier circuit comprising an active device, a DC blocking element and an oscillating element, wherein the oscillating element is driven by a voltage signal.

Abstract: An antenna comprises a polarizer, a phasing network and a field radiating element such as a horn. The polarizer and phasing network generate a plurality of phase shifted circularly polarised waves which are superimposed to produce multiple antenna field patterns from a single antenna aperture.

Abstract: Method and apparatus for providing an amplified modulated radio frequency signal, the method comprising the steps of providing a radio frequency (RF) oscillatory signal, generating from the RF oscillatory signal and an input signal a pair of phase modulated phase conjugated signals, and summing said pair of signals to provide the desired modulated RF signal output. A form of the invention is applied to digital modulation using in-phase (I) and quadrature (Q) input signals. Each of the I and Q signals is processed in a respective channel, with the channel outputs being summed. The channels share an RF oscillatory signal, which is phase shifted by 90 degrees within the Q channel.

Abstract: A composition suitable for coating fabrics is provided. The composition comprises a halogen-containing copolymer of a C.sub.4 to C.sub.7 isomonoolefin and a para-alkylstyrene; a filler; a processing aid, and a curing agent. A fabric coated with the composition is also provided.