Unemployment insurance consists of two parts. One of these parts is voluntary, income-related insurance which provides compensation based on your previous income. Compensation from this insurance is paid out to those who are members of an unemployment insurance fund.
The other, which is the basic insurance, means that only a basic amount is paid out to those who are not members of an unemployment insurance fund or who have not been members for a sufficiently long time to be entitled to income-related compensation.
You find more information at the Swedish Public Employment Service's website (Arbetsförmedlingen): Financial support for jobseekers