Send unencoded query parameters in Ember

I'm working with an API that only accepts unencoded query parameters. I notice that when I make a query in Ember like so:

this.store.query('listing', {filter: params});

The uri is encoded when it hits the api:

/v1/listing?filter%5Bcategory%5D=123

What I need is for the query parameters to get to my API unencoded, eg:

/v1/listing?filter[category]=123

Can anybody give me a steer on what is the right way to do this in Ember?