Relation between EM frequency/Intensity and voltage/current in a Circuit
In an EM wave, there are actually 3 characteristics (actually there's even more, but they aren't as important here): frequency, electric field strength and magnetic field strength. The "electric" and "magnetic" components of the wave is why it's called an EM ("electromagnetic") wave. the E component can be thought of as related to voltage in a transmission line, and the M component related to the current flowing in that transmission line. The E and M components are related by the characteristic impedence of the medium through which they are travelling. (Interestingly, even a vacuum has a characteristic impedence for RF/MW.) Like electricity flowing in a wire, the power in the wave is proportional to the product of the electric and magnetic field strengths.

So, to get back to your question, in an RF wave, frequency does not correspond to voltage, in general. And both the voltage (electric field) and current (magnetic field) have corresponding intensities.

Just to confuse things and (almost) completely change the topic, there is a fundamental physical relationship known as Planck's equation, and is expressed by the equation E = hν. Here, "ν" is the Greek letter "nu" (not the English "vee", even though in this website's font it looks the same), and represents frequency. "h" is known as Planck's constant, and E is energy. So here it seems like the energy is proportional to frequency. But this relation only holds on an atomic scale for a single "photon" of energy, which is a much, much smaller quanta of energy than anything we measure in electric circuits or communications. So although Planck's equation might look like it's related to your question, and may even be the origin of your "frequency corresponds to voltage" statement, the scale of Planck's phenomenon is far too small for consideration in normal RF and MW applications.