Q: iOS personal hotspot does not let any device connect after a connection from a 5 GHz band

I used my iPhone 5 with latest iOS version. When I connect my iphone to a 5GHz band at home and then ON the Personal Hotspot (PH), my ipad mini retina can't connect to the wifi of the iphone, it said "Unable to connect". I tried it with my laptop and got the same result. But if I disconnect it from the 5GHz and reconnect to a 2.4GHz band (at home too), then turn on PH, it will let other device connect normally.

I know that I can solve the problem by connect to a 2.4GHz and then turn on PH. But the problem is when I go out, every wifi around me is password protected, and I need to share PH to my laptop. it just won't connect. Do a Network reset solve the problem too, but when I come back home and connect to my 5GHz band, the problem still raise, PH will not let any device connect to it until I connect my iphone to a 2.4GHz and then turn on PH again.