Here is an aire based on a disused municipal campsite. Not sure whether it is open in winter as we called by at New Year several years ago and it was closed. It's on a ring road but is a large grassy area set well back from the road.
Entry in Camping Car Infos
2020 ANTWERPEN/ANVERS (Antwerpen)
Latitude : (Nord) 51.18957° Décimaux ou 51° 11′ 22′′
Longitude : (Est) 4.40064° Décimaux ou 4° 24′ 2′′
Also this campsite which is closed in winter, but we parked in the entrance road at New Year along with a few other vans. From here it is about a mile to the pedestrian tunnel under the Schelde into the heart of the old city.
Correction to my post above - I have somehow copied the same CC-Infos entry twice; both refer to the site on a ring road. Here is the site that is about a mile from the pedestrian tunnel under the Schelde. I notice that there is also a reference to 6 all-year places on an aire.