bannerView = new BannerView(adUnitId, AdSize.SmartBanner, AdPosition.Bottom);
// Register for ad events.
bannerView.AdLoaded += HandleAdLoaded;
bannerView.AdFailedToLoad += HandleAdFailedToLoad;
bannerView.AdOpened += HandleAdOpened;
bannerView.AdClosing += HandleAdClosing;
bannerView.AdClosed += HandleAdClosed;
bannerView.AdLeftApplication += HandleAdLeftApplication;
// Load a banner ad.
bannerView.LoadAd(createAdRequest());
bannerView.Show();
So I am using SmartBanner and at Bottom.
Same implementation gives correct ads on ipad. (some kind of ads shown, correctly fits on the device whose screen shot was attached)