An omnidirectional antenna array comprising a ferrite antenna inductively coupled to one leg of a loop antenna that lies in a plane parallel to the long axis of the ferrite antenna The output signal may be taken from either of the antennas

Compact omnidirectional antenna array

The invention relates to a loop antenna tuned by means of a variable capacitor. The antenna includes, in parallel with the variable capacitor (4), a switchable state variable inductor (11). The invention is particularly applicable to antennas for HF radio links at powers of up to 1 kW.

Tuned band-switching loop antenna

of the Disclosure A phase front homing system airborne antenna array which employs portions of the airframe as two antenna elements and wherein each antenna element includes a coaxial sleeve coupler.

Inconspicuous antenna system employing the airframe as an antenna

Multi-stage reduction of impact forces are disclosed. An example apparatus to reduce impact energy of an aircraft during landing includes a rotatable landing leg having a proximal end near an axis of rotation and a distal end opposite the proximal end, a first flexible portion of the proximal end, where the first flexible portion is to engage a first engaging portion at a first rotation angle of the rotatable landing leg, and a second flexible portion of the distal end, where the second flexible portion is to engage a second engaging portion at a second rotation angle of the rotatable landing leg.

Multi-stage reduction of impact forces

A multiband antenna includes one or more first antennas embedded within a second antenna The one or more first antennas can include a folded dipole, and the second antenna can include a monopole The folded dipole and the monopole may operate at different resonant frequencies Because the folded dipole is embedded in the monopole, rather than being a separate antenna, near-field coupling between the antennas may be reduced, resulting in enhanced radiation patterns by one or both antennas More complex antenna structures can also be constructed having multiple antennas embedded within one or more antennas

Multiband embedded antenna

The struts which are disposed perpendicular to the roll axis of a helicopter for supporting the landing skids thereof are insulated from the helicopter fuselage. One of the struts has an antenna feed at its center, whereby the entire landing gear assembly functions as a folded dipole antenna or a loop antenna, depending on the operating frequency.

Watson P Czerwinski

Papers

Helicopter skid antenna