spiralEquiangular
Create equiangular spiral antenna
Description
The spiralEquiangular
object is a planar equiangular spiral
antenna on the xy- plane. The equiangular spiral is always center fed
and has two arms. The field characteristics of the antenna are frequency independent. A
realizable spiral has finite limits on the feeding region and the outermost point of any
arm of the spiral. This antenna exhibits a broadband behavior. The outer radius imposes
the low frequency limit and the inner radius imposes the high frequency limit. The arm
radius grows linearly as a function of the winding angle. As a result, outer arms of the
spiral are shaped to minimize reflections.
The equation of the equiangular spiral is:
, where:
r0 is the starting radius
a is the growth rate
ϕ is the winding angle of the spiral
Creation
Description
creates a
planar equiangular spiral in the xy- plane. By default,
the antenna operates over a broadband frequency 4–10 GHz.se
= spiralEquiangular
creates an equiangular spiral antenna, with additional properties specified
by one, or more name-value pair arguments. se
= spiralEquiangular(Name,Value)Name
is the
property name and Value
is the corresponding value. You
can specify several name-value pair arguments in any order as
Name1
, Value1
,
...
, NameN
, ValueN
.
Properties not specified retain their default values.
Properties
Object Functions
show | Display antenna, array structures or shapes |
info | Display information about antenna or array |
axialRatio | Axial ratio of antenna |
beamwidth | Beamwidth of antenna |
charge | Charge distribution on antenna or array surface |
current | Current distribution on antenna or array surface |
design | Design prototype antenna or arrays for resonance around specified frequency |
efficiency | Radiation efficiency of antenna |
EHfields | Electric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays |
impedance | Input impedance of antenna; scan impedance of array |
mesh | Mesh properties of metal, dielectric antenna, or array structure |
meshconfig | Change mesh mode of antenna structure |
optimize | Optimize antenna or array using SADEA optimizer |
pattern | Radiation pattern and phase of antenna or array; Embedded pattern of antenna element in array |
patternAzimuth | Azimuth pattern of antenna or array |
patternElevation | Elevation pattern of antenna or array |
rcs | Calculate and plot radar cross section (RCS) of platform, antenna, or array |
returnLoss | Return loss of antenna; scan return loss of array |
sparameters | Calculate S-parameter for antenna and antenna array objects |
vswr | Voltage standing wave ratio of antenna |
Examples
References
[1] Dyson, J. The equiangular spiral antenna.” IRE Transactions on Antennas and Propagation. Vol.7, Number 2, pp. 181, 187, April 1959.
[2] Nakano, H., K.Kikkawa, N.Kondo, Y.Iitsuka, J.Yamauchi. “Low-Profile Equiangular Spiral Antenna Backed by an EBG Reflector.” IRE Transactions on Antennas and Propagation. Vol. 57, No. 25, May 2009, pp. 1309–1318.
[3] McFadden, M., and Scott, W.R. “Analysis of the Equiangular Spiral Antenna on a Dielectric Substrate.” IEEE Transactions on Antennas and Propagation. Vol. 55, No. 11, Nov. 2007, pp. 3163–3171.
[4] Violakis, John Antenna Engineering Handbook, 4th Ed., McGraw-Hill.
Version History
Introduced in R2015a