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What is the equation for radiation pattern of a half wave dipole antenna?
Wiki User
∙ 12y ago
E=sin(Theta);
You need to normalize the equation for the electric field of the half-wavelegnth dipole. recall E=sqrt(ExE*) where E* is the conjugate of the E field.
This is why you only get an eight shaped figure (or infinity symbol) when you plot it. you will get this figure if the dipole is placed in the axis of interest. e.g. if it is in the placed in the x axis, you will get an eighth in the x-y,x-z, but you will get a donut shape in the y-z (no angle to measure)
hope this helps a bit.
Wiki User
∙ 12y ago
Wiki User
∙ 12y agoIn free space it's 492 divided by the frequency in MHz. However, there is no such thing as free space in the real world so the better and more accepted formula is 468 divided by the frequency in MHz.
It's normally a good practice to cut your dipoles a little long and then trim them down to resonance with an SWR bridge. You just keep trimming equal amounts off each side till you get a 1:1 SWR ( or as close as you can get)
Wiki User
∙ 13y agoTry re-submitting the question with more detail on exactly what you want to know !
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What is the difference between yagi antenna and dipole antenna?
I don't think it has. Bandwidth depends on the diameter to length ratio of the antenna. The greater the diameter of the elements the wider the bandwidth. The inductance goes down and the capacitance goes up, giving the antenna a lower Q. the folded dipole has a greater effective diameter (at least double for the same materials). You can increase a normal dipole's bandwidth by increasing the diameter, hence the old time birdcage aerials.
Why dipole antenna not used for high frequency?
Depends on what you mean by high frequency. The rabbit ears antenna used in broadcast TV is a dipole and is used for VHF.
Claculate the length of the dipole antenna at 450 MHz?
245
Why High frequency reduce the size and weight of components?
The concept is, greater the frequency less will be the size of antenna and weight. For example the Mobile Phone uses the half wave dipoles antenna. There is no exact formula for calculating these antennas. The problem is that there are several factors that affect the antenna. Fortunately there is a starting formula for these types of antennas. For center fed, wire dipole antennas, the formula is length of antenna = 468/freq (MHz). Mobile phone in GSM working on the frequencies 900 MHz and 1800 MHz so put the values in the formula you get your answer. If you move further in the frequency band the size will be more small.
Does shape of the antenna effect the magnetic field?
Yes for instance a dipole will have a doughnut shape field and a directional like a yagie will have a long teardrop shape field at the front end and a shorter teardrop field at the rear and some smaler fields sideways and a parabolic disc wil have a very long teardrop shape field
What is the value of radiation resistance of half wavelength dipole antenna?
36 ohm
What is the difference between yagi antenna and dipole antenna?
I don't think it has. Bandwidth depends on the diameter to length ratio of the antenna. The greater the diameter of the elements the wider the bandwidth. The inductance goes down and the capacitance goes up, giving the antenna a lower Q. the folded dipole has a greater effective diameter (at least double for the same materials). You can increase a normal dipole's bandwidth by increasing the diameter, hence the old time birdcage aerials.
Thr radiation pattern in plane perpendicular to Hertizian dipole is.?
It's a torus.
Is folded antenna nothing but the conical antenna?
A folded antenna is a dipole type.
What is the half wave dipole?
effective height of half wave dipole antenna
Why dipole antenna not used for high frequency?
Depends on what you mean by high frequency. The rabbit ears antenna used in broadcast TV is a dipole and is used for VHF.
The type of antenna used for the television broadcasting?
Dipole
How loop antenna and dipole antenna can be used interchangeably?
A full-wave loop antenna can be interchanged with a folded dipole without much difference. The input impedance is similar and the only difference is in the directivity: a full wave loop radiates along the axis of the loop, while a vertical folded dipole is omnidirectional.
Claculate the length of the dipole antenna at 450 MHz?
245
What are the advantage of trap dipole antenna?
A dipole antenna, is a radio antenna that can be made of a simple wire, with a center-fed driven element. It consists of two metal conductors of rod or wire, oriented parallel and collinear with each other (in line with each other), with a small space between them. The radio frequency voltage is applied to the antenna at the center, between the two conductors. These antennas are the simplest practical antennas from a theoretical point of view. They are used alone as antennas, notably in traditional "rabbit ears" television antennas, and as the driven element in many other types of antennas, such as the Yagi. Dipole antennas were invented by German physicist Heinrich Hertz around 1886 in his pioneering experiments with radio waves.
When a vertical dipole antenna is used in conjunction with a loop antenna for direction finding then the field pattern obtained will be?
Loop antenna generate the same field as electrical dipole, but E and H are exchanged (a proof can be obtained this way: you align an electrical dipole with an axis, say z, and a loop antenna with z - you have to define surface orientation - then you apply duality theorem, calculate far field and you got it). For instance, in spherical coordinates (r,phi,theta) you have el. dipole {Etheta,Hphi} loop ant. {Ephi,Htheta} So, you can superpose the two fields and see that you have gained polarization independency (if an electrical dipole is aligned with z-axis and has its gap at z=0, it will receive very well Etheta, not at all Ephi (plane z=0), if you put a loop antenna "around" electrical dipole - like a ring around dipole's gap, lying on z=0 plane - it will receive very well Ephi (plane z=0) ). This is the way to make triaxial sensor, which have to be polarization independent.
What is the Application of Rhombic antenna?
dipole antennas evolved antennas ground anteena
