2007-03-25 22:47:48 · 6 answers · asked by e r 1 in Science & Mathematics ➔ Engineering
You guys just made those answers up. .
it is not the length at all
It has to do with impedance
the voltage and amperage that a wave generates as it hits the antennae, and the carrying capacity of the transmit ion lines leading into your cir cuts
Antenna matching: The process of adjusting impedance so that the input impedance of an antenna equals or approximates the characteristic impedance of its transmission line over a specified range of frequencies. Note: The impedance of either the transmission line, or the antenna, or both, may be adjusted to effect the match.
2007-03-25 23:08:53 · answer #1 · answered by Anonymous · 0⤊ 1⤋
For maximum power transfer impedance has to match. The lower the frequency of signal then the longer the wave length. The antenna does have to be at least half the wave length to receive a good signal.
2007-03-26 00:55:30 · answer #2 · answered by mad_jim 3 · 0⤊ 0⤋
Do a search on "maximum power transfer theorem".
For maximum power transfer to a load, the impedance of the load (in this case the antenna) must match ("be the same as") the impedance of the power source.
The impedance of an antenna can vary enormously, depending on physical size, frequency in use, and so forth.
In a practical set up, it is convenient to have some matching device, which is effectively a radio frequency transformer, in order to get as much as possible of the power generated by a transmitter radiated from the antenna.
This also applies to reception. In this case you want as much of the received signal power as possible delivered to the receiver's input.
2007-03-25 23:18:08 · answer #3 · answered by lunchtime_browser 7 · 0⤊ 0⤋
you match the impedance and the length
the transmitter sends out a wave, if the antenna is wrong it wont match the signal say the waveform is a meter long. you need a meter long antenna or a fraction of it like half meter quarter meter. etc. the impedance needs to match to or you wil reach the end of the antenna and bounce the signal back through the line to the transmitter burning it out
2007-03-25 22:55:24 · answer #4 · answered by Justin H 4 · 0⤊ 0⤋
it's the process of determining the optimum length of the transmission line between the antenna and the transmitter/receiver. as well as the presence of series or parallel stubs. to ensure the optimum transfer of the power from transmitter to antenna or from antenna to receiver. where the smith chart is widely used in this purpose.
2007-03-26 00:10:49 · answer #5 · answered by Hamdi 2007 2 · 0⤊ 0⤋
The antennae "length" must be proportional to the frequency WAVE LENGTH to be more efficient.
If you transmit (receive) on 1m wave-length, your antennae must be 1m long (or a fraction such as 1/2, 1/4, 1/8, or a multiple such as 2m, 4m etc...)
That is "matching".
2007-03-25 22:54:32 · answer #6 · answered by just "JR" 7 · 0⤊ 0⤋