I've tried everything and still am unable to join my own wifi network from my iPhone 4s

@musthear

Are you getting any error messages?

Have you tried to "forget" the network?

You can try getting your MAC addresses reset on each device. Contact your Carrier for this.

Can you try connecting to the AirPort Extreme with any other devices apart from the MacBook and iPads?

Last option is to contact Apple.

Saying you tried everything isn't helpful. Perhaps describing in detail what you've done would allow people to better assist you.

If you're ever experiencing strange problems connecting to any wifi point you can always try resetting your network settings on your iPhone itself. This solves the majority of wifi problems.

To do this go to Settings > General > Reset > Reset Network Settings. This will clear all of your saved wifi hotspots and passwords, and hopefully solve your issue.

Please try this and respond with your results.

As I understand, three different versions of iPhones will not connect to your Airpot Extreme. Are these devices able to connect to other wifi routers? If so it seems your Airport is faulty.

Make sure your Airport Extreme is broadcasting 2.4 GHz g/b/n and not just 5 GHz n. Here's a longer list of troubleshooting steps http://support.apple.com/kb/TS1398.

When you're trying to connct are you able to see the Airport in your list of available routers?

Would you describe the error you receive when you try to connect?

Do you have the AirPort Utility on your iPhone?

Have you been able to connect in the past?

Ok so I think it's safe to say you probably don't have a hardware problem.

Have you tried following the steps in the above linked support article?