Dotcast e-field antenna promises improved OTA DTV, HDTV reception
Aug 16, 2004 2:39 PM, RF Update e-newsletter, By Rob Cummings
 Dotcast’s antenna technology combines a simple electric field (e-field) sensing structure coupled to an electronic amplifier that presents a very high impedance across its input terminals. |
This fall, a new antenna design based on Dotcast’s e-field technology will be available at consumer electronics stores.
The antenna will deliver significant improvements in over-the-air digital and high-definition reception and enable DTV off-air reception in neighborhoods and buildings where it currently isn’t feasible.
Dotcast’s antenna technology combines a simple electric field (e-field) sensing structure coupled to an electronic amplifier that presents a very high impedance across its input terminals.
This amplifier transfers any voltage presented across its input to a resistive load across its output. As the amplifier input impedance approaches infinity, the amount of power consumed from the sensing structure approaches zero.
This antenna has an inherently wide bandwidth because the electric-field sensing structure responds only to the integral of the electric field applied along the length of the structure and presents a voltage proportional to the applied field at the sensing terminals. When coupled with the high-impedance amplifier, it benefits from an enormous power gain. Because it is a nonlinear system, achieving a multiple octave bandwidth for required television reception is simple.
An added benefit of the using a simple electric-field sensor as a sensing structure is the ability to design antenna systems with excellent directivity in a compact physical envelope. Dotcast’s first directive model fits in a box that is four by five inches square and 22 inches long, but performs as well as a traditionally styled, five-foot log-periodic already coupled with a low-noise amplifier.
Visit Dotcast to learn more about the new antenna design.
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