[![enter image description here](https://i.stack.imgur.com/qZnal.png)](https://i.stack.imgur.com/qZnal.png)I'm looking at the datasheet for the analog devices hmc431lp4 voltage controlled oscillator, and I can't tell if its output waveform is a sine wave or square wave. The datasheet doesn't label the oscillator as being harmonic or relaxation. I'm wondering because I am trying to understand a homemade radar system I found online. Do FMCW systems like this project require a sinusoidal RF signal to operate?

Link to [datasheet](https://www.analog.com/media/en/technical-documentation/data-sheets/hmc431.pdf).

Link to [project](http://hforsten.com/homemade-synthetic-aperture-radar.html) I'm looking at.