A planar reflectarray system provides for bandwidth broadening by employing a tunable (amplitude and phase) feed array. The tunable feed array is adjustable in amplitude and phase to compensate for aberrations by enabling feed re-focusing and field matching. The techniques modestly increase the size of the feed array and use active tuning to effectively correct for de-focusing when operating reflectarrays at frequencies away from the tuned center frequency.

Embodiments of the present invention relate to a chaff electronic countermeasure device. The device comprises an antenna that is in communication with a substrate. An integrated circuit is in electrical communication with the conductive antenna element. The conductive antenna element includes a conductive composition. The conductive composition includes a conductive polymer and graphene sheets. The device is configured to absorb from a radar source a first radio frequency having a first amplitude. The device is configured to absorb from a radar source a first radio frequency having a first amplitude. In response to absorbing the first radio frequency, the device is configured to reradiate at least a portion of a second radio frequency having a second amplitude toward the radar source, which results in an increased radar cross section of the device as perceived by the radar source. The second amplitude is higher than the first amplitude.

There is provided an apparatus and method for disrupting radar systems. The apparatus comprises a chamber (110) for attachment to a vehicle, a radar countermeasure material (130) in the chamber, the radar countermeasure material comprising a plurality of hollow fibres, wherein the inner surface of at least some of the hollow fibres is at least partly coated with a conductive substance, and a release means (140) for dispensing the radar countermeasure material out of the chamber.

A metallic component including a metallic material and having a skin depth of greater than or equal to 1.0 m in a frequency range from 20-40 GHz, as calculated by:

[00001]$=\sqrt{\frac{2.Math.}{\left(2.Math..Math..Math.f\right).Math.\left({}_0.Math.{}_r\right)}}5.Math.0.Math.3.Math.\sqrt{\frac{}{{}_r.Math.f}}.$

In this equation, is skin depth in meters (m); is resistivity in ohm meter (.Math.m); f is frequency of an electromagnetic radiation in hertz (Hz); .sub.0 is permeability; and .sub.r is relative permeability of the metallic material. The metallic component may be a discrete metallic particle or a layer in a multilayer thin film.

A metallic component including NiCr and having a skin depth of greater than or equal to 1.0 m in a frequency range from 20-40 GHz, as calculated by:

[00001]$=\sqrt{\frac{2.Math..Math.}{\left(2.Math..Math..Math..Math.f\right).Math.\left({}_0.Math.{}_r\right)}}503.Math..Math.\sqrt{\frac{}{{}_r.Math.f}}.$

In this equation, is skin depth in meters (m); is resistivity in ohm meter (.Math.m); f is frequency of an electromagnetic radiation in hertz (Hz); .sub.0 is permeability; and .sub.r is relative permeability of the NiCr metallic material. The metallic component may be a discrete metallic particle or a layer in a multilayer thin film.

The invention relates to a device for seeding a cloud cell, comprising a pyrotechnic torch containing an active substance. The invention further relates to a pneumatic projection apparatus for projecting such a device, the apparatus comprising a guide element and a fastener, which fastener is arranged to cooperate with the distal portion of a projection base of the device. The invention also relates to a system for seeding a cloud cell.

A multiple co-frequency microwaves detection antenna includes an oscillation circuit unit, a reference ground and at least two radiation sources. The radiation sources each has a feed point and are arranged spacedly at the reference ground. A radiation gap is formed between each of the radiation sources and the reference ground. The feed point of the radiation source is electrically connected to the oscillating circuit unit.

A method includes transmitting, by a radiofrequency identification (RFID) reader device, a first electromagnetic radiation at a first polarization to a scan area and second electromagnetic radiation at a second polarization to the scan area. Re-radiated first electromagnetic radiation is received from an RFID tag located in the scan area at the first polarization. Re-radiated second electromagnetic radiation is received from the RFID tag at the second polarization. A radar image is generated based on the first and second re-radiated electromagnetic radiation. One or more items of information encoded in one or more microstructure elements located on the RFID tag are decoded based on the generated radar image. An RFID reader device and an RFID system are also disclosed.

A planar reflectarray system provides for bandwidth broadening by employing a tunable (amplitude and phase) feed array. The tunable feed array is adjustable in amplitude and phase to compensate for aberrations by enabling feed re-focusing and field matching. The techniques modestly increase the size of the feed array and use active tuning to effectively correct for de-focusing when operating reflectarrays at frequencies away from the tuned center frequency.

Embodiments of the present invention relate to a chaff electronic countermeasure device for protecting mobile platforms against radio frequency threats. A device comprises an antenna that is in communication with a substrate. An integrated circuit is in electrical communication with the antenna. The device is configured to absorb from a source a first radio frequency having a first amplitude. In response to absorbing the first radio frequency, the device reradiates at least a portion of a second radio frequency having a second amplitude toward the radar source, which results in an increased radar cross section of the device as perceived by the radar source. The second amplitude is higher than the first amplitude.