How does the champions matchmaking work?

Would be nice to know how the matchmaking works. Today I played my first champs ever, and after getting completely shit on in the first two games I already thought, well this will fun. But after that I went on a 8 games win streak, which was really easy (all opponents quit after the first 2 or 3 goals which was roughly at the 30min mark all the time).

So being 8-2 and having really easy games the last 8 games I thought, maybe I can even get to 11 wins. Well the last 5 games I again was completely destroyed without even the chance of scoring.

So that made me wonder how the matchmaking works. From other games I know that most of the time the games try to match you with the same skill. In champions that would be playing against the same standing (probably +-1) but from the experience today this totally didn't feel like this.