Each team has a Team Rating

From Team Ratings to Arena Points The Arena System is meant to primarily reward competitiveness and player skill, and this is reflected in the way Team Ratings, Arena Points, and Arena Rewards tie into each other.
Each team has a Team Rating. This rating reflects how well your team is doing in the Arena System; the higher your rating, the better. When you queue up for a fight, the matchmaking system uses your rating to find a suitable match if the average personal rating is a 150 points range of the team rating. Every time your team wins a match, your rating goes up, and every time you lose a match, your rating goes down. The amount by which your rating changes depends on your team's rating compared to the other team's rating – if you win against a higher ranked team, your rating will improve more than if you steamrolled a weaker team. Similarly, losing against a weaker team will hurt your rating more than losing against superior enemies. The exact formulae are a bit more complicated than that, but the basic idea is similar to the Elo ranking system used for professional chess.
At the end of each week, your Team Rating is used to calculate how many Arena Points your team will receive for the week. Your team must have fought a minimum of ten matches per week to be rewarded with Arena Points, and a player must have been in at least 30% of all your matches to be eligible for that week's points. It is important to note that the points you receive in a given week is determined by only one team, and not from a combination of all your teams. Whichever team you are a member of that would receive the most points after accounting for Team Rating and team type becomes the sole source for your points for that week.
The transformation from your Team Rating to Arena Points starts off as a linear function, but once you go beyond a certain rating threshold, the function becomes logistic. This means that you will see a significant payoff increase once your Team Rating goes beyond a certain point, but the high-end spectrum of the ratings will eventually notice a decrease in how much bang they get for their buck. In addition, 2v2 and 3v3 teams are subject to a handicap where they receive less points than a 5v5 team with the same Team Rating.