Phase matched Antennas
I have two antennas and I want to measure the phase difference between them.
I know that the best theoretical way to do this is at an antenna range by measuring the phase of S21, but since this is not very practical to me I would like to do this by measuring the pase of S11 of the antenna when it faces the sky.
Is this a good Idea? can anyone think of a better way to do the measurement?
10x,
Sag
So many other factors enter in that your most accurate way is to put them into the environment they will be used in and measure the difference to a receiving antenna. This includes the same type and length of transmission line.
that will not help me because it is as difficult as doing this in an antenna range.
I need a simple way to do this...
As you have everyting under control: create a signal, point both antenna's to is and feed the antenna and signal also to a mixer: the dc component is a measure for the phase difference, if you clip both inputs to the mixer, it is even exact.
Or, feed both signals from the antenna to a mixer and measure the dc component.
I assume you would like 0 degrees difference and have a means of correcting it.
Square two sin waves and see what happens if you shift one phase compared to the other: Max in phase, max dc; neg out of phase result is max negative and 0 dc component meanse exactly 180 degrees phase difference. To get the dc component you have to integrate the product of the signal: put in a condensor which is a low impedance at the freq of interrest. OK?