Coefficients and harmonics of a PWM signal
The Fourier coefficients are, in every case, just a computation of CORRELATION between the input waveform and the sin/cosine basis functions.
Hint Hint--- &quot;harmonics&quot; are a mathematical contrivance.
Think what new design freedom you have, what bandwidth of circuits (poor correlation), you may acquire if you debate the existence of &quot;harmonics&quot;.
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Example: you have a MCU with 10MHz clock, with 1nanosecond ramp_edges on the clock. That 1nS ramp_edge produces correlation of sin(X)/X energy shaping, with the first null out at 1,000MHz, the 2nd null at 2,000MHz..
Now on that same die with the MCU, implement a radio receiver. Should you pick 310MHz as the carrier (exactly the 31rst integer multiple of the MCU clock) or pick 313MHz (which is 31.3X  MCU clock)?
How do you decide?
Now let me also tell you that the input PI matching, from antenna to Low_Noise Amplifier, has Q of 10 for easy manufacturability given component tolerances.
How do you decide on the Carrier frequency?
Given the Q (bandwidth being 313/10 == 31MHz widh or +-15.5 MHz at the 3dB points), what does matter?