madbilly
Casual Member
Hi everyone,
Another question that I'm trying to work out the answer to: when comparing antenna specs/datasheets, can I consider that 2x2 MIMO gain is effectively twice the SISO gain, if the MIMO antennas are linearly aligned/polarised? Similarly would 4x4 MIMO be 4x SISO gain? (I know that dB is log-scale so 2x6dB is 9dB, I think?)
How about if the MIMO antenna is cross-polarised? Does the max gain of two 6dB cross-polarised antenna that are 90 perpendicular to one another equal 6dB x cos(45) (4.5dB for one antenna) + 3dB (doubling by adding the second antenna) = 7.5dB? That's if the wave is between the two, oriented 45 degrees to each antenna; if the wave is aligned with one antenna and therefore not at all aligned with the other then the max gain would be 6dB.
So, potentially a linearly-aligned MIMO antenna can give much more gain, but only if it's well aligned. A X-Pol MIMO antenna has a lower potential max gain but can more reliably pick up a signal in any orientation?
This finally leads me to ask - do datasheets for MIMO antennas show the max gain of all antenna combined or of each antenna?
Cheers
Another question that I'm trying to work out the answer to: when comparing antenna specs/datasheets, can I consider that 2x2 MIMO gain is effectively twice the SISO gain, if the MIMO antennas are linearly aligned/polarised? Similarly would 4x4 MIMO be 4x SISO gain? (I know that dB is log-scale so 2x6dB is 9dB, I think?)
How about if the MIMO antenna is cross-polarised? Does the max gain of two 6dB cross-polarised antenna that are 90 perpendicular to one another equal 6dB x cos(45) (4.5dB for one antenna) + 3dB (doubling by adding the second antenna) = 7.5dB? That's if the wave is between the two, oriented 45 degrees to each antenna; if the wave is aligned with one antenna and therefore not at all aligned with the other then the max gain would be 6dB.
So, potentially a linearly-aligned MIMO antenna can give much more gain, but only if it's well aligned. A X-Pol MIMO antenna has a lower potential max gain but can more reliably pick up a signal in any orientation?
This finally leads me to ask - do datasheets for MIMO antennas show the max gain of all antenna combined or of each antenna?
Cheers























