Optimizing Antenna Efficiency: Matching Frequency and Waveform

AI Thread Summary
Antenna efficiency is influenced by the matching of frequency and waveform, with a dipole antenna typically resonating around 70 ohms. When using a square wave generator with a duration of one microsecond, the fundamental frequency is indeed 1 MHz, accompanied by odd harmonics. The third harmonic is three times the fundamental frequency, while the fifth is five times, each with decreasing amplitude. For optimal radiation from a dipole, the generator's output frequency must align with the dipole's resonant frequency, which can vary based on waveform duration. Ultimately, matching the generator's output to the antenna's resonance is crucial for efficient radiation.
Mica
Messages
32
Reaction score
0
Hi,

I want to clarify some notiona in an antenna. The major components of an antenna are a generator, transmission line and an antenna (dipole). Let's say the whole system has a perfect matche, i.e. the dipole is about 70 ohms as the transmission line. If my generator ,the output voltage, is an impulse which has a duration in a micro second ( let's say 1 micro sec). So, the frequency of this generator is 1 Mhz? If the impluse is a square, the main fundamental frequency is 1 MHz and also , with others harmonics, I means if I do the Fourier Transformation am I right?

Thanks,

Mica
 
Engineering news on Phys.org
A square wave is composed of odd integer harmonics. The third, fifth, seventh, and higher order odd harmonics all have power in them.

- Warren
 
chroot said:
A square wave is composed of odd integer harmonics. The third, fifth, seventh, and higher order odd harmonics all have power in them.

- Warren
How can I determined these odd integer harmonics ? and if is another wave form ? And the calculation of the power of these harmonics ?

Thanks,

Mica
 
Last edited:
http://mathworld.wolfram.com/FourierSeriesSquareWave.html

Look at equation 6.

The third harmonic has a frequency three times that of fundamental, and has an amplitude one-third that of the fundamental. The fifth harmonic has a frequency five times that of the fundamental and an amplitude one-fifth that of the fundamental.

- Warren
 
Thanks for the information. So, for my dipole radited efficiently, I just match the right frequency output of the generator ? I mean like if my dipole resonances at 1 GHz so, my impluse (voltage source) duration will be 1/1 GHz ( 1 nano second) independent of the wave form?

Mica
 
Thread 'Weird near-field phenomenon I get in my EM simulation'
I recently made a basic simulation of wire antennas and I am not sure if the near field in my simulation is modeled correctly. One of the things that worry me is the fact that sometimes I see in my simulation "movements" in the near field that seems to be faster than the speed of wave propagation I defined (the speed of light in the simulation). Specifically I see "nodes" of low amplitude in the E field that are quickly "emitted" from the antenna and then slow down as they approach the far...
Hello dear reader, a brief introduction: Some 4 years ago someone started developing health related issues, apparently due to exposure to RF & ELF related frequencies and/or fields (Magnetic). This is currently becoming known as EHS. (Electromagnetic hypersensitivity is a claimed sensitivity to electromagnetic fields, to which adverse symptoms are attributed.) She experiences a deep burning sensation throughout her entire body, leaving her in pain and exhausted after a pulse has occurred...
Back
Top