The electromagnetic wave can send an image, which is directly recognized in the brain, not through the eyes. However, its image is not visualized clearly, which is more like a vague shape recognized with a verbal information supportedly sent in the brain. It means there is a limitation at the imaginary resolution, which is more visualized with a support of the memory.
When you see a scenery, you do not see a scene just in front of you. The world is filled with the light, whose optical wavelength is received by the eyes, and then it is transformed into the electric signal. This signal is recognized as a vision with a support from the memory as well.
When we find out a methodology to convert a light to the electric signal in the same way as the retina does, and if we can find out a way to send it to the brain directly, we recognize the same image just in the brain sent by the electromagnetic wave as the eyes see the world. It is nearly the same as sending an information digitally, and if we achieve that technology, the brain manipulation is enhanced to the next level.
However, we are not yet to that level, as it is impossibly difficult. The retina has many cells, each of which is directly linked to the visual area of the brain. The electric signal is sent as a pulse rather than frequency, hence if you would like to recreate this function, you need to send an information by a similar pulse, which is apparently more than current technology based on the very-low frequency and chemical reaction.
Having said that, this electromagnetic wave can deliver and create an image, mixed up with other information in the brain. It means the vision is not necessarily dependent on the eyesight. This visualization occurs in the visual cortex, which is directly affected by the radiowave, hence you can visualize a vague image from the wave, which becomes more concrete with other information, such as verbal.
When you close your eyes, you can visualize the image inside your mind. It might be beautiful, but you cannot image it in the same resolution as the eyesight can do. This is pretty much the same as the image sent by the electromagnetic wave. If you would like to increase its resolution, you need to upgrade it with a lot of help from the memory.
This is another bottleneck of the electromagnetic wave manipulation that the memory address is so individually unique that you cannot control it by the wave. It is more difficult than to control the visual. Although, the verbal can be used as a supplement to retrieve the memory. I mentioned many times this is verbal, but it does not have a sound, actually. It is enough with a thought arising in the brain accompanied by a vague image, which is mixed up to visualize a more concrete figure.
In this way, the radiowave can make you see something, but it is still vague. The only time I had a clear view is when I was drugged by the intelligence agents. Under this circumstance, your vision becomes clearer, which is, of course, the same as a hallucination. However, there is one critical issue that I cannot differentiate its image coming from the electromagnetic wave or created by the hallucination.
Furthermore, it is too dangerous to drug someone unnoticeably.