The antennas proposed in this study have two different versions, where the first one possesses better omnidirectionality and axial ratio
performances but narrow frequency bandwidth, and the second one has wider bandwidth but lower omnidirectional and axial ratio
The antenna axial ratio
in the most cases is less than 3dB, but precisely because of the higher requirements of Omni-directional, in the high-frequency pattern the axial ratio
appears between 4-5 dB additionally, this antenna's back coaxial impedance matching SMA connectors take a longer length, increasing the size of the antenna.
16 illustrates the axial ratio
of array for the -3 dB beamwidth in two planes at the center frequency.
Figure 9 shows the comparison of the axial ratio
of Antenna-2 at lower band and upper band with different side length of square notches of the outer slot and inner slot, respectively.
Figure 21 shows the simulated and measure axial ratios
for the circular polarization operations.
In fact, abandoning the constraint on the inhibition of surface waves , the proposed antenna can easily obtain with the characteristics of a 3 dB axial ratio
at lower elevation and a radiation pattern roll-off from zenith to horizon higher than 10 dB.
These wafer-thin galaxies have axial ratios
ranging from 9:1 to 20:1 and consist of gasrich late-type spirals (Sc, Sd, or Sm) that lack a discernible bulge or organized dust lane.
The very good axial ratio
found on the model W 131 identifies the drawings as representing crystals of wurtzite.
Iqbal, "Design of circularly polarized omnidirectional bifilar helix antennas with optimum wide axial ratio
beamwidth," Progress In Electromagnetics Research C, Vol.
However, the axial ratio
(AR) bandwidth is very narrow.
If the axial ratio
is less than 3 dB over any frequency band, then the antennas are said to be circularly polarized in that frequency band.
Simple instructions for installation and use are provided in the hardcopy book, and the CD also includes a Mineral ID Calculator that can perform all suggested calculations based on observations in the manual, including specific gravity, symmetry, axial ratio
, position in series based on density or refractive index, and optic axial angle (2V).