115 results about "Front-to-back ratio" patented technology

A band clamp for coupling a radome to a distal end of a reflector dish for improving the front to back ratio of a reflector antenna, is provided with an inward projecting proximal lip and an inward projecting distal lip. The distal lip is dimensioned with an inner diameter equal to or less than a reflector aperture of the reflector dish. The proximal lip may be provided with an inward bias dimensioned to engage the reflector dish in an interference fit and / or turnback region dimensioned to engage an outer surface of a signal area of the reflector dish in an interference fit. A variety of different configurations of protruding portions extending from the band clamp may be applied to further improve electrical performance.

An oriented PIFA-type apparatus for reducing hearing aid radio frequency (RF) interference including a directional multi-band and / or single band antenna for use with PWDs such as digital cellphones is disclosed. The apparatus greatly reduces or eliminates the audio noise induced in hearing aids by the PWDs and allows operation of a hearing aid during PWD operation. In operation, the apparatus may be provided on the PWD side away from the user's head. The apparatus may be integrated into the PWB during its manufacture or provided as an after market assembly for a PWD that has a port for connection of an external antenna. The apparatus provides for improved front-to-back ratio as compared to antennas currently in use on PWD's, and therefore also reduces SAR (specific absorption rate), the level of RF energy received into the head by a PWD.

An antenna system with at least one tunable dipole element with a length adjustable conductive member disposed therein that enables the antenna to be used over a wide range of frequencies. The element is made of two longitudinally aligned, hollow support arms made of non-conductive material. Disposed longitudinally inside each element is a length adjustable conductive member electrically connected at one end. In the preferred embodiment, each conductive member is stored on a spool that is selectively rotated to precisely extend the conductive member into the support arm. The support arms, which may be fixed or adjustable in length, are affixed at one end to a rigid housing. During use, the conductive members are adjusted in length to tune the element to a desired frequency. The antenna is especially advantageous when configured as a Yagi-style antenna that can be optimally tuned at a specific frequency for maximum gain, maximum front-to-back ratio, and to provide a desired feed point impedance at the driven element. The antenna can also function as a bi-directional antenna by adjusting the reflector element to function as a director. An electronic control system allows the length of the conductive members to be manually or automatically adjusted to a desired frequency.

An antenna system with at least one tunable dipole element with a length adjustable conductive member disposed therein that enables the antenna to be used over a wide range of frequencies. The element is made of two longitudinally aligned, hollow support arms made of non-conductive material. Disposed longitudinally inside each element is a length adjustable conductive member electrically connected at one end. In the preferred embodiment, each conductive member is stored on a spool that is selectively rotated to precisely extend the conductive member into the support arm. The support arms, which may be fixed or adjustable in length, are affixed at one end to a rigid housing. During use, the conductive members are adjusted in length to tune the element to a desired frequency. The antenna is especially advantageous when configured as a Yagi-style antenna that can be optimally tuned at a specific frequency for maximum gain, maximum front-to-back ratio, and to provide a desired feed point impedance at the driven element. The antenna can also function as a bi-directional antenna by adjusting the reflector element to function as a director. An electronic control system allows the length of the conductive members to be manually or automatically adjusted to a desired frequency.

An antenna system with at least one tunable dipole element with a length adjustable conductive member disposed. The element is made of two longitudinally aligned, hollow support arms made of non-conductive material. Disposed longitudinally inside each element is a length adjustable conductive member electrically connected at one end. Each conductive member is stored on a spool that is selectively rotated to extend the conductive member into the support arm. The support arms are affixed at one end to a rigid housing. During use, the conductive members are adjusted in length to tune the element to a desired frequency. The antenna can be optimally tuned at a specific frequency for maximum gain, maximum front-to-back ratio, as a bi-directional antenna, and to provide a desired feed point impedance. An electronic control system allows the length of the conductive members to be manually or automatically adjusted to a desired frequency.