Particle rotate around center

I am trying to create a power range indicator and have icons rotate around the power structure to show that power radius when building selected…

Only I have not been able to successfully been able to get this this work…

my current particle effect the orbit rotate of the four particle wobbles up and down and is rather random, how can I fix it to just rotate orbiting from center axis and set offset of spawn particles to be even from that center in all directions?