Terms starting with ‘F’
- Fan-beam Antenna
- A directional antenna which produces a main beam having a narrow beamwidth in one dimension and a wider beamwidth in the other dimension. This pattern will be achieved by a truncated paraboloid reflector or a circular paraboloid reflector. Since the…
- Far-field Radiation Pattern
- A radiation pattern measured at the far field of an antenna or other emitter.
- Far-Field Region
- Generally refers to the distance an antenna is being measured from. These areas are generally determined by the size of the wave. The distance of one wavelength is generally referred to as “near-field” while two wavelengths is generally referred…
- Refers to the components of an antenna which feed the radio waves to the rest of the antenna structure, or in receiving antennas collect the incoming radio waves, convert them to electric currents and transmit them to the receiver.
- Fractal Antenna
- An antenna that uses a fractal, self-similar design to maximize the length, or increase the perimeter (on inside sections or the outer structure), of material that can receive or transmit electromagnetic radiation within a given total surface area…
- The number of cycles per second of a sound wave.
- Frequency Bandwidth
- The range of frequencies within which the performance of the antenna, with respect to some characteristics, conforms to a specified standard. Voltage Standing Wave Ratio (VSWR) of a wireless antenna is the main bandwidth limiting factor. See also:…
- Fresnel Zone
- The area around the visual line-of-sight that radio waves spread out into after they leave the antenna. This area must be clear or else signal strength will weaken. (Pronounced "Fre-nel" with a silent "s".)
- Front-to-back Ratio
- Describes the ratio of power gain between the front and rear of a directional antenna. In other words, the ratio of received-signal strength when the antenna is rotated 180º backwards.