If you get a device such as the TP-Link RE200 AC750 WiFi Range Extender, it can act as a WiFi to Ethernet adapter. Then set your dual band router to use different network names (SSID) on the 2.4 GHz and 5 GHz bands. Then you set the RE200 to use the network name that is on the 5 GHz band.
You can connect the Ethernet port of the RE200 to a PC or similar device and you will get 5 GHz WiFi converted to Ethernet to a computer. It will give you only 100 Mbps Ethernet, as that is the maximum speed of the Ethernet port. Other makes and models may support 1000 Mbps Ethernet and faster 5 GHz speeds.
I hope this helps.
You don't connect to 5GHz through ethernet. 5GHz is a WIRELESS band. The ethernet ports on your router would use either 10/100/1000 BASE-T. 1000Base-T is gigabit ethernet and is generally the fastest ethernet currently available on a consumer router. There's also 10GbE which is blazing fast compared to everything else but not yet widely available in the market or still super expensive where it is available.
Essentially to get faster ethernet (if that's what you're trying to do) you'd have to upgrade your ethernet ports which would involve replacing hardware. Don't forget you would need to upgrade all ports in between your computer and router to remove all bottlenecks. If your router has gigabit ethernet and your computer only has a 10BASE-T NIC then you're only going to get 10BASE-T speeds at the max.
You can NOT connect to wifi thru Ethernet! EITHER you connect wirelessly to wifi, OR you connect wired thru the Ethernet.
You can't connect via Ethernet. 5Ghz is a WiFi connection.
You can, however, connect to the router via Ethernet and then use that connection to configure the WiFi. Is that what you mean?
Ethernet is a wired connection. I think you mean "how do I connect to the 5GHz band instead of the 2.4Ghz band on my router". On the router, name your 5Ghz band like a different network (i.e. Mynetwork-5). Connect to that, and you should be fine.
With the ethernet we can't use 5GhZ OR 2 GhZ
a 5Ghz wifi card is backwards compatible with 2.4Ghz wifi signal.
you CANNOT connect at the 5Ghz speed though.
you can only connect at 5Ghz if both the card and the wifi source supports it.