I'm wondering if you want to make a real non-alcoholic beer or just something that satisfies like beer but is not beer and not alcoholic. Beer is about the only alcoholic drink i truly enjoy, but what i like about it is the bitterness. Personally, i wouldn't find lemon to be anything near it. Lemon is sour, beer is bitter (well some ales are sourish, but i don't like them much, but that;s personal taste).
There are some roots that are bitter, and other substances that could be used to make a sort of beerish drink. In Italy they make a dark drink that looks like cola but is made of china (pronounced keena) which, i believe, is a very bitter orange. But that's got sugar in it. The resulting soft drink is a very adult taste, bitter-sweet.
The other thing is that beer is not carbonated, and the bubbles are more creamy - they;re very tiny and the result of yeast growing.
Beer is made from barley malt i believe (or occasionally other malts, like wheat malt (correct me if i'm wrong) in "weiss" beer. and rice in some asian beers. Here, again, in Italy there is a drink called "orzo" which is toasted barley, and they use it to make a coffee substitute and a brand called Kneipp is made of toasted malted barley. Malted barley is barley that's been allowed to sprout, i believe. (For sure others more knowledgeable can tell you these things more correctly, but since no one is bothering to answer you I'm trying, but take what i say with a grain of salt!) So theoretically, you could sprout barley, toast it, and grind it and make a sort of coffee, which would be like the malt in beer. But beer contains hops. So then what? And it's fermented.
the father of a friend of mine used to make real rootbeer - which was made of roots, bitter roots, or at least the extracts from those roots, and was actually fermented (he used yeast) and put in bottles then it would foam up on opening. It was not sweet.
I would be curious how they do make alcohol-free beer - i presume it;s fermented but then maybe the alcohol is somehow eliminated, but how? i don;t know.
For a very thirst quenching bitter bubbly drink, try grapefruit. but it won;t resemble beer.