Antenna Definition and 418 Threads

Hi let's suppore that an antenna creates two signals... The two signal are received from an other antenna but with a main difference. The one of the two signal is reflected in a surface which means that it will travel bigger distance... The two signals are received with a difference in the...

Antenna array consists of two infinite plane parallel sheets in the xy plane spaced half a wavelength apart and having current densities. Wave is propagating in vacuum. J_{s1} = J_{so}cos(\omega t) \vec{i} z = 0 J_{s2} = J_{so}sin(\omega t) \vec{i} z = \frac{\lambda}{2} The...

hi all, can any one help me to solve a wire of antenna by method of moment by using pocklington integral equation and MATLAB or fortern code in need the code please help me because this is my graduation project thanxxxxxxxxxx sad rose

What affects the size of the amplitude of a wave sent by an antenna?

I have a weird question I think... I'de like to know how low a frequency and how high a current can a wireless device transmit. eg, radio frequency is over 1000s of Hz, can it be much lower than that?When you receive a radio signal to an antenna, a small current is generated which is...

Can pigtail cable be substitute with coaxial cable?

Because of its direct link to self-fields such as described in the EM self-field theory, I want to talk about how antennas can be designed to emit zero nett radiation. Although antennas were shown by Hertz in 1888 to 'always' emit radiation he used only one antenna, a wire halfwave dipole with...

I have been looking for info on the physical basis for this antenna equation : Gain = 4 * Pi * (Effective Area ) / Wavelength^2 I have found some tutorials that say it is based on reciprocity, and more specifically, on thermodynamic balance between a resistive load connected to an antenna...

I have a satellite antenna in my backyard (the big antenna, not the small one from Direct TV) and I don't know how to use it. I did some research and I think it's called the C-band antenna and I do have to pay around $30 for service/month just like we have to pay for cable TV. I have a receiver...

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...

Hi, If my input voltage the wave form is a sin or a triangle in a dipole antenna, what is the difference between these two wave forms? Thanks, Mica

Hello all, I have this weird idea for a cell phone booster antenna and I thought i would run it past you all here to see if it could work. Where I live, we get really bad reception inside our house so I commonly have to step outside and use my cell phone in the driveway to get a decent...

I am aware of the apperent presence of electrons on the [flat, top] base of an antenna such as one on a radio. I took the time to obtain a magnet with moderate strength. I placed the magnet about a centimeter away from the [flat] base of the antenna and found it vibrated. As I decreased the...

Just wondering if anyone happens to have an electromagnetic diagram of how a four antenna array would look. Provided that all four antennas’ form a square and edges are one wavelength in distance? Thanks Philip

what makes antenna to radiate,the basic principle... :smile:

If light is just an EM phenomena like radio waves (with more energy) would it be possible to build a transmitter that transmits in the light range? If you were to do this, would you see light that just seems to propagating from the antenna?

Lets take a unidirectional antenna. The waves you acquire are transformed into light that you can see. You designate the freq. into specific colours and what would you see?

OK here is what I am trying to figure out there is a large factory by my house which towers about 4 stories above the surrounding community. on the roof there is an array of 802.11b anttenas (im assuming its B and not A cause B has larger range) there are 10 large anttenas, 5 on one side of...