special purpose antenna

8/4/2019 Special Purpose Antenna

1/64

Folded Dipole

Yagi-Uda

Log-Periodic


2/64

Folded Dipole Antenna


3/64

Dipole Antenna


4/64



5/64

Dipole

Antenna

Folded Dipole

Antenna


6/64

Folded Dipole AntennaDesign

L = 143/f

where:L is in meters

f is in MHz

L = 468/fwhere:

L is in feet

f is in MHz


7/64

Folded Dipole AntennaDesign folded dipole uses a 300 ohm balanced feeder line

elements can be any conductor from simple wires to copper or

aluminum tubing

tips of the antenna are folded back until they almost meet at the

feedpoint, such that the antenna comprises one entire wavelength


8/64


Where:d1 is the conductor diameter for the feed arm of the dipoled2 is the conductor diameter for the non-fed arm of the dipoleS is the distance between the conductorsr is the step up ratio

Design


9/64

Folded Dipole AntennaVoltage and Current


10/64

Folded Dipole AntennaDescriptiona dipole antenna whose outer ends are folded back and

joined together at the center;

the impedance is about 300 ohms, as compared to 70 ohmsfor a single-wire dipole;


11/64

Folded Dipole AntennaApplicationused in the simple FM dipole antennas that can be bought to

use as temporary FM broadcast antennas

used within other larger antennas such as the Yagi.

used to raise the impedance to a suitable value

well matched to 300-Ohm balanced transmission lines

widely used with television and frequency-modulation

receivers.


12/64



13/64

Yagi-Uda Antenna


14/64

Yagi-Uda Antenna


15/64

Yagi-Uda Antenna


16/64

Yagi-Uda AntennaThe Elements of a Yagi

The Driven Element

where feed point is locatedand where the feed line isattached from the transmitterto the Yagi to perform thetransfer of power from thetransmitter to the antenna

resonant when the electricallength is 1/2 of the

wavelength, for the usedfrequency, applied to the feed

point


17/64


Parasitic Elements

- element that is not directlyconnected to the feed line

- elements used for the purpose ofobtaining directional power gain

- reradiate power which they receivefrom the driven element

Directors

Reflectors


18/64


Parasitic Elements

Directors slightly higher in frequency

than the driven element

length is 5% shorterprogressively than thedriven element

used to provide theantenna with directionalpattern and gain


19/64

Yagi-Uda AntennaThe Elements of a Yagi Parasitic Elements

Reflector

protect the antenna againstthe parasitic signalscoming from the rear

resonant frequency is lowerand length is 5% longer

than the driven element the spacing will be between

.1 and .25 wavelength

Prevents antenna fromsending backward


20/64

Yagi-Uda AntennaDesignThere are no simple formulas for designing

Yagi-Uda antennas due to the complexrelationships between physical parameters suchas element length, spacing, and diameter, andperformance characteristics such as gain and

input impedance.Wikipedia

http://en.wikipedia.org/wiki/Yagi-Uda_antenna


21/64

Yagi-Uda AntennaDesign Guidelines

typical spacing between elements vary from about 1/10 to1/4 of a wavelength, depending on the specific design

elements are usually parallel in one plane, supported on asingle crossbar known as a boom.

the elements must be made of some kind of conducting material:

copper, aluminum, coaxial cable are best suited.

with coaxial cable, we can use only the shield or connect the shield

with the inner conductor. the horizontal stick (boom) can be made of anything.

if it is made of conducting material, the elements must be isolated

from the stick.


22/64



23/64









from the stick.


24/64



25/64









from the stick.


26/64



27/64


Driven Element

typically a

/2 dipole or

folded dipole

electrically

connected tothe feedline

Director/s

length is 5% shorter

progressively than the

driven element

the directors should

be roughly 1/4 awavelength apart

Reflector

length is5% longerthan thedrivenelement


28/64

Yagi-Uda AntennaThe Elements


29/64

Yagi-Uda AntennaDesignthese antennas are often empirical designs

using an element of trial and error, oftenstarting with an existing design modified

according to one's hunch. The result might bechecked by direct measurement or by computer

simulation.Wikipedia

http://en.wikipedia.org/wiki/Yagi-Uda_antenna


30/64

Yagi-Uda AntennaDesign

http://www.changpuak.ch

/electronics

/yagi_uda_antenna.php


31/64

Yagi-Uda Antenna**** YAGI UDA ANTENNA ****Design by www.changpuak.ch

---------------------------------------------------

Frequency : 100 MHz

Wavelength : 3000 mm

d/lambda : 0.003 ( min.: 0.001 , max.:

0.04 )D/lambda : 0.007 ( min.: 0.002 , max.:

0.04 )

Boomlength : 1200 mm

Elements : 3

Gain : 7.1 dB (approx.)

---------------------------------------------------

Reflector Length [mm] : 1463

Reflector Position [mm] : 0---------------------------------

Dipole Length [mm] : 1446

Dipole Position [mm] : 600

---------------------------------

Director Length [mm] : 1388

Director Position [mm] : 1200

---------------------------------

Calculations based on NBS TECHNICAL NOTE688

Len th mi ht be sli htl too lon .


32/64

Yagi-Uda Antenna

http://www.k7mem.150m.com/Electronic_Notebook/antennas/yagi_vhf.html#Introduction


33/64

Yagi-Uda AntennaDesign

YagiMAX: Yagi Uda antenna modelling software

YagiMAX Screenshots

http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


34/64

Yagi-Uda AntennaDesign Equal spaced, equal length directors may give higher gain at a

particular frequency, but the bandwidth is more narrow and largersidelobe levels are created.

Wide spacing will increase the bandwidth, but the sidelobes becomelarge.

By varying both the spacing and director lengths the pattern andthe pattern bandwidth may be more controlled.

More directors within a given boom length won't increase the gainby any great amount, but will give better control of the antenna'spattern over a wider range of frequencies in the band of design.

If the length of each succeeding director is reduced by a set factor(%), and increase the spacing of each succeeding director byanother factor, a very clean pattern with good pattern bandwidthcan be obtained. The trade off will be a small loss in the optimumforward gain (10% to 15%).

http://www.hamuniverse.com/yagibasics.html
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


35/64

Yagi-Uda AntennaDescriptiona directional antenna designed to maximize

reception over long distances

familiar as the commonest kind of terrestrial TVantenna to be found on the rooftops of houses

used at frequencies between about 30MHz and3GHz, or a wavelength range of 10 meters to 10cm

the typical directivity is between 7dB and 9dB

named after two Japanese scientists whoinvented it
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


36/64

Yagi-Uda AntennaApplication

used for amateur radio used during World War II for airborne radar sets

used for local television reception
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


37/64

Log Periodic Antenna


38/64

Log-Periodic Antenna


39/64

Log-Periodic Antenna


40/64

Log-Periodic AntennaDesign

Typically,

Typically,
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


41/64

Log-Periodic AntennaDesign Bandwidth:

Number of Dipoles:
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


42/64

Log-Periodic AntennaDesign the length and spacing of the elements of a log-

periodic antenna increase logarithmically fromone end to the other

diminish in size from the back towards the front element at the back of the array is a half

wavelength at the lowest frequency of operation

element spacing decrease towards the front ofthe array

the feed phase is reversed from one element tothe next to ensure that the phasing of thedifferent elements is correct

the direction of maximum radiation is towardsthe feed point
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


43/64

Log-Periodic AntennaDescription the antenna input

impedance variesrepetitively when

plotted as a function offrequency andperiodically whenplotted against the logof the frequency

able to provide

directivity and gainwhile being able tooperate over a widebandwidth
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


44/64

Log-Periodic AntennaDescription the radiation pattern of this RF antenna design stays broadly the

same over the whole of the operating band as do parameters likethe radiation resistance and the standing wave ratio

it offers less gain for its size than does the more conventional Yagi


45/64

Log-Periodic AntennaApplication used where a wide range of frequencies is needed while still having

moderate gain and directionality

used on the HF portion of the spectrum where operation is required ona number of frequencies to enable communication to be maintained

used at VHF and UHF for a variety of applications, including some usesas a television antenna
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


46/64

Turnstile Antenna


47/64

Turnstile Antenna


48/64

Turnstile AntennaDesign consists of two horizontal half-

wave antennas mounted atright angles to each other in

the same horizontal plane


49/64

Turnstile AntennaDesignRadiation Pattern

The radiation pattern shown is the sum of radiation patterns from the

two dipoles, which produces a nearly omnidirectional pattern
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


50/64

Turnstile AntennaDescription a set of two dipole antennas aligned at right angles to each other and

fed 90 degrees out-of-phase

When mounted horizontally the antenna is nearly omnidirectional onthe horizontal plane.

When mounted vertically the antenna is directional to a right angle toits plane and is circularly polarized.


51/64

Turnstile AntennaApplication developed primarily for omnidirectional vhf communications

often used for communication satellites because, being circularlypolarized, the polarization of the signal doesn't rotate when thesatellite rotates


52/64

Helical Antenna


53/64

Helical Antenna


54/64

Helical AntennaDesign The dimensions of the helix are determined

by the wavelength of the radio wavesused, which depends on the frequency.

In axial-mode operation, the spacingbetween the coils should be approximatelyone-quarter of the wavelength (/4), andthe diameter of the coils should beapproximately the wavelength divided by pi(/)

The length of the coil determines

how directional the antenna will be as wellas its gain; longer antennas will be moresensitive in the direction in which they point.

a ground plane at the driven end makes theradiation unidirectional from the far (open)end
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


55/64

Helical AntennaDesign


56/64

Helical AntennaDesign

Where:

is the radius of the helix is the pitch angle

S is the spacing between turns

L is the length of one turn

is the tangential unit vectordescribing the contour of the helix

Zo is the starting height of the helix
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


57/64

Helical AntennaDesignpitch angle :

where:

s is the spacing from turn to turn

is the radius of the helix


58/64

Helical AntennaDesign The helical countour can be described by

The x and y coordinates are given by


59/64

Helical AntennaDesign the spacing b/w turns can be written as

z coordinate is given by

Combining the above relationships give

which describes any point on helix
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


60/64

Helical AntennaDesign can be written in cylindrical coordinates by

using

and

giving


61/64

Helical AntennaDesign the two equations are used in the development

of the electric field integral

equation for the helix


62/64

Helical AntennaDesign The ground plane diameter is typically

0.94 in diameter at the centerfrequency

the radiating element is a helix ofwire, driven at one end and radiatingalong the axis of the helix
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


63/64

Helical AntennaDescription An antenna that has the form of a helix
http://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.htmlhttp://please.name.my/70/yagimax-great-yagi-uda-antenna-modelling-software.html


64/64

Helical AntennaApplication typically used for applications where reduced size is a critical

operational factor

most suitable for Mobile and Portable High-frequency (HF) communications in the

1 MHz to 30 MHz operating range

used extensively for 27 MHz CB radio

special purpose antenna

Documents