How to implement AdMob in Phonegap

I have a phonegap application and am trying to implement Admob.

I use the telephone version 1.4.1 and I use this site as a link: http://iphone.keyvisuals.com/iphonedev/implementing-admob-ads-in-a-phonegap-project-for-ios-no-plugins -required /

My code is as follows:

(void)webViewDidFinishLoad:(UIWebView *)theWebView
{

bannerView_ = [[GADBannerView alloc]init];
[bannerView_ setDelegate:self];
[bannerView_ setFrame:CGRectMake(0, 0, 320, 50)];

// Specify the ad "unit identifier." This is your AdMob Publisher ID.
bannerView_.adUnitID = MY_BANNER_UNIT_ID;

// Let the runtime know which UIViewController to restore after taking
// the user wherever the ad goes and add it to the view hierarchy.
bannerView_.rootViewController = self.viewController;
[self.viewController.view addSubview:bannerView_];

// Initiate a generic request to load it with an ad.
[bannerView_ loadRequest:[GADRequest request]];

// only valid if AdGap.plist specifies a protocol to handle
if(self.invokeString)
{
    // this is passed before the deviceready event is fired, so you can access it in js when you receive deviceready
    NSString* jsString = [NSString stringWithFormat:@"var invokeString = \"%@\";", self.invokeString];
    [theWebView stringByEvaluatingJavaScriptFromString:jsString];
}
return [ super webViewDidFinishLoad:theWebView ];
}

Everything is fine, but when I launch the application, the ads do not appear.