public float GetPixelToPointFactor()
    {
        BannerView banner = new BannerView(BannerId, AdSize.Banner, AdPosition.TopLeft);

        return AdSize.Banner.Width / banner.GetWidthInPixels();
    }

    public float GetScaleFactor()
    {
        float scaleFactor = 0;
        if (scaleFactor == 0) scaleFactor = GetPixelToPointFactor();
        return scaleFactor;
    }

    public void RequestBanner()
    {
        AdSize adSize = new AdSize(300, 250);


        int w;
        int h;
        if (Screen.dpi < 250)
        {
            w = 280;
            h = 200;
        }
        else
        {
            w = 75;
            h = 50;
        }

        int xLocation = (int)(((float)Screen.width * 0.3125f) * GetScaleFactor());
        int yLocation = (int)(((float)Screen.height / 2f) * GetScaleFactor());
        if (xLocation < 0) xLocation = 0;

        int adX = xLocation - (w / 2);
        int adY = yLocation - (h / 2);

        bannerView = new BannerView(BannerId, AdSize.MediumRectangle, adX, adY);

        AdRequest request = new AdRequest.Builder().Build();


        bannerView.LoadAd(request);
    }