While investigating various wireless routers I became interested in measuring what the power emitted from various devices. I picked out the Cornet ED78S to use as testing as it measures between 100MHz and 8.0GHz. There is a Cornet ED85EXA model which measures 1MHz-8GHz but it requires a special separate antenna, without the antenna its range is 700MHz to 6.0GHz. Please note this is only a single-axis meter so it will depend on where your head/body is in-relation to the phone, in this example I put them side by side. This is for informational purposes only. Any type of measurements should be taken with multiple devices that are calibrated to confirm accuracy and preferably with a tri-axis meters, although those can be quite expensive.
There are other videos on YouTube which show the differences if the meter is directly in front of the iPhone such as this one here, please note he is using mW/m2 in the video below.