Recent content by Mica

Thanks for the detailed explanation. Does existed a formula or a textbook that explained the limitation of d? What I mean is at some point (dmax) the V will decrease instead of increasing. I would have a formula or a graphic shows this behavior. I saw a paper in MEMs that they varie the...

When you say small, what is the ratio for it? In the last case, d is constant. What kind of material is with a dielectric high as 1000 to 10,000? The material with the highest dielectric constant is 10 that I know. I don't quite understand that the fringe field out in the aire is tiny? What...

I'm thinking of some kind of dipole, but I can not connect the equations together. I don't kown. So, what happens when I decrease the area of the plate? If I have two same parallele plates initially then, I slide one of them to decrease the length. Is it the same explanation as above...

The formula to calculate the capacitance is C = (epsilon*A/d). Let say I have two plates of 1m x 1m, d = 0.03m and epsilon = 3.2 then C = 0.9 nF. If I able to separate the plates (d increase) then my capacitance decreases. Assuming charges conservation, Q0 = V0 * C0 and Q0 = Vf* Cf, then I can...

Sorry, I have long time that I did not solve a differencial equation. Can you give me its form? thanks, Mica

Hi, Can someone give me a hint for solving this equation? V0 - dQ(t)/dt * R(t) - Q(t)/C(t) = 0 Thanks, Mica

Thanks, this is clear. Does exist a software which I can design simple antenna system i.e. changing parameters of the generator, transmission line and see the output of the antenna system? It doesn't need to be in one software, severval softwares will be fine. Right now, I'am using NECWIN95 for...

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

Why I cann't drive my antenna directly from the source? For example, if I have a dipole which it resonne at 1.5 GHz, let's say perfect match, so the frequency of my generator should by 1.5 GHz? The duration of my impluse should by 66 nano second (1/1.5 GHz) ? It doesn't matter the output of the...

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

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...

Maybe I'm missing something. Just a simple calcule, Input let's say , V = 100 volts V = Z*I at resonnance, Zdipole = 73 ohm Idipole = 1.36 A For folded dipole, Zfolded = 300 ohm Ifolded = 0.33 A Output power, P = 1/2 *Z*I*I Dipole P = 1/2 * 73* 1.36 *1.36 = 67.51...

Hi, What is the advantage to have a folded dipole? Well, the radiation pattern, the output power are the same? Except for the radiation resistance, but I don't understant, the resistance is 4 time the dipole so, why the output power is the same? Thanks, Mica

Thanks for all the information. Now, it clarify a little better for me. Thanks for this open forum, it helps me a lot and I can find answer that I don't need to run around and end up with nothing. I need a good book for starter in understanding Antenna. I need a book which has a lot for...

O.K. I explain what I understand in antenna. First, an antenna is a open circuit, right? So, to drive an antenna, you need an input source (voltage)which gives the antenna to radiated. Roughly speaking, the whole system is composed a generator and an antenna, right? The output of the generator...