Sorry for such a late post!
When I think of juxtaposition in Owen’s “Anthem for Doomed Youth,” irony comes to mind. The title itself is a denigration against the war. An anthem is defined as a “song or hymn of praise or gladness” (Merriam-Webster’s Collegiate Dictionary), which counterpoises the tone of the poem. Throughout the poem, the speaker is mourning the soldiers’ deaths (the poem is an elegy). Although the speaker of the poem laments over the soldiers’ deaths, there is a more dreadful idea—the idea of the “Doomed Youth”; as soldiers lose their lives, people lose their sons, fathers, brothers, and uncles ultimately affecting future generations. Juxtaposition can also be seen between the octet and sestet. The octet (first eight lines) makes use of the present tense—in the midst of battle; the sestet uses the future tense—the speaker looks inwards (inner experience). Owen does not only criticizes the war, but he tries to make his audience question their beliefs by showing what happens to men who die in battle: they cannot be properly honored and their families (especially the Youth) suffer.