which microwave oven is the smallest for gas ranges?

So the smallest over-the-range microwave is the slimline ones from Whirlpool and KitchenAid. These are fairly new models made when a consumer is replacing a hood. It hangs much higher and gives more clearance above the stove.

https://www.whirlpool.com/kitchen/cooking/microwaves/over-the-range/p.1.1-cu.-ft.-low-profile-microwave-hood-combination.wml75011hz.html