What is the best dog door that lets dogs in/out but keeps neighbors cats out?

There are doors that connect with your dog's collar signal. Not really expensive but a few hundreds for the whole system.

I have 4 dogs yorkie, morkie, shih tzu, and a chiu/dash/poodle mix. We need a dog door that isnt real expensive but will allow the dogs axcess in and out but will keep my cat and the neighborhood critters out.

There are an array of new doggie doors to choose from, now, at stores like Home Depot, and other Department stores..There's a new item, that's now selling, that looks like a collar, that you put around your dogs neck and as he approaches the doggie door, an electronic beam opens it. It closes back, after he enters. It's designed to keep critters and other un wanted (s) from being able to follow them inside...unless they have on a collar programmed to open your doggie's door...Good luck.