Wireless performance degradation when using same U.FL connector for both 2.4GHz and 5GHz antennas

[dilation]

There are some routers use the same U.FL connector for both 2.4GHz and 5GHz antennas (especially those with external antennas), whereas, some routers use separate U.FL connectors for 2.4GHz and 5GHz antennas.

Would the former design in any way negatively affect the router's wireless performance when both frequencies are used?

 

[sfx2000]

There are some routers use the same U.FL connector for both 2.4GHz and 5GHz antennas (especially those with external antennas), whereas, some routers use separate U.FL connectors for 2.4GHz and 5GHz antennas.

Would the former design in any way negatively affect the router's wireless performance when both frequencies are used?

Antenna design - different impedance matches - good RF engineer knows how to make this work...

(hence the risks of non-matched antennas)

 

[pete y testing]

Would the former design in any way negatively affect the router's wireless performance when both frequencies are used?

any situation where you merge 2 bands into one you sacrifice tuning of one frequency to accommodate the other , the connector would however play no part in this as its just a pure connection

if the 2.4 gig and 5 gig antennas are separate the antennas will be specifically tuned to the frequency band

the reason to have dual band routers was so you didnt have an antenna farm jutting out from the router , however looking at the asus rt-ac5300 ascetics dont seem to count anymore

 

[stevech]

There are some routers use the same U.FL connector for both 2.4GHz and 5GHz antennas (especially those with external antennas), whereas, some routers use separate U.FL connectors for 2.4GHz and 5GHz antennas.

Would the former design in any way negatively affect the router's wireless performance when both frequencies are used?

Connector per band lets you use band-specific antennas and that can get you a few dB over a dual-band antenna. But small benefit compared to path loss in typical WiFi use. need 10's of dB to make a real difference.

 

[sfx2000]

if the 2.4 gig and 5 gig antennas are separate the antennas will be specifically tuned to the frequency band

the reason to have dual band routers was so you didnt have an antenna farm jutting out from the router , however looking at the asus rt-ac5300 ascetics dont seem to count anymore

Two common ways - first is the Dipole antenna that folks see on Router/AP's - you know, those little plastic things...

A dual band antenna is typically two - a long wire for one band, and a helical for the other, like this...

"==========/=/=/=/=/"

The "=" is the lower band, and the "/" is a helical wrap - they both have different impedance characteristics, so one can play with resistors/capacitors/inductors to match the different radios to the radiated elements...

Note - many of the "high gain" external antennas found on eBay/Amazon - they're not matched, and many are actually very poorly designed and rarely perform as well as the OEM antennas - despite vendors promises..​

Internal Antennas - most common these days are PIFA's - where again, we play with lengths of metal - even circuit traces, and feed the output/inputs of the radio on different lengths - this is especially helpful with multiple bands like we see on Mobile Phones - where we have to cover frequencies from 700MHz, to 800MHz, to 850Mhz, to 1800Mhz, 1900MHz, and 2100MHz, and a couple in-between - prevents the "porcupine" impact when trying to have a really nice looking industrial design for smart phones...

 

[sfx2000]

however looking at the asus rt-ac5300 ascetics dont seem to count anymore

That's intentional on Asus part - it's part of the design and the intended market they're going after with that device...

Look at their Republic of Gamers Laptops - pretty much the same thing...

 

[stevech]

spending bux on costly WiFi router won't fix poor coverage.