To help you assemble a technical specification for your antenna, a list of key parameters affecting the design of an antenna is provided below. A very brief explanation is provided for each parameter. If you are composing a specification and cannot determine a parameter's appropriate value or type, you may provide a description of the application (focus on desired end result or goals, how it will be used and where it will be used). From your description, we can complete your specification.

For any assistance you may need in creating your antenna specifications, and for any questions regarding your antenna needs, do not hesitate to contact us. We make it our business to solve your antenna problems.

 

Passive Antennas:

  • ANTENNA PATTERN: desired performance of antenna as a function of direction (two dimensions: Azimuth and Elevation)
  • AXIAL RATIO: measure of antenna circularity or quadrature balance on its axis of symmetry (often the zenith). Use for circularly polarized antennas only
  • BANDWIDTH, 3 dB: immediate frequency range where antenna performs at least half as well as it does at its optimum frequency (usually resonance)
  • BANDWIDTH, "x.x" VSWR: immediate frequency range where antenna impedance mismatch equates to a VSWR of "x.x" or lower
  • BEAMWIDTH, 3 dB: angular spread where antenna performs at least half as well as it does in its peak direction
  • DIRECTIVITY: the idealized gain of the antenna at its peak direction
  • DISTANCE TO OTHER OBJECTS AND GROUND: self explanatory
  • DUTY CYCLE: the ratio of time the antenna is fed radio power to the total period. Mainly used for antennas subject to high power pulses, or antennas with built-in limiters or EMP protection.
  • FREQUENCY of OPERATION: desired operating center frequency
  • GAIN: actual gain of the antenna at its peak direction
  • IMPEDANCE, RF: the desired complex ratio of voltage to current at the antenna connector, at the design frequency (typically 50 Ohms, real)
  • IMPEDANCE, DC: the desired ratio of voltage to current at the antenna connector for a Direct Current (can be measured with a simple voltmeter). Typically, this value is either approximately 0 Ohms (short circuit) or very large, depicted as infinite Ohms (open circuit.) A short circuit value is desirable to help protect the transmitter circuitry and the feedline from static energy. If you expect your device to operate in static prone environments, you should request that the DC short circuit impedance have a high ampacity (able to carry a large current), or specify the desired current handling capability in Amperes.
  • POLARIZATION: the orientation of the electric field a great distance from the antenna. Appropriate types are: Linear, Vertical; Linear, Horizontal; Linear, Oblique; Circular, Right Hand (RHCP); Circular, Left Hand (LHCP); Elliptical, Right Hand and Elliptical, Left Hand. Typically, your application will require either one of the three Linear polarizations or one of the Circular polarizations.

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