What's the VSWR requirement of antenna

[winglj]

what is vswr antenna

I have a question about designing antenna. For cellular & PCS dual band antenna, what's the VSWR requirement if I use PIFA or L's structure? Is it 2 acceptable without using match network?
BTW: How to design the match network for dual-band? Any refereces or examples are appreciable.

 

[boy]

VSWR = 2 is ok for the receiver about 80% will be received. for TX, it should be abour 1.5. VSWR 1.25 is very good. I think there are many ways to design dual frequency PIFA without any matching network. You might search the forum. I have seen many disscusionds.

 

[flatulent]

You should use the impedance (real and imaginary) to make your decision. Reactive loads reduce the linearity of linear amplifiers. They can usually be corrected with a series or shunt reactance.

Once you know the antenna impedance and the required load at the source or collector of your amplifier transistor, you can design the network between them. It is not necessary to convert to 50 ohms at the midpoint.

 

[vfone]

Theoretically PIFA has 50 ohms port termination, and do not requires any lumped element for matching and thus avoid any losses due to that.

**broken link removed**

The impedance matching of the dual band PIFA is obtained by positioning of the single feed and of the 2nd band cutting slot.

VSWR limit it depends by your system design. For example in CDMA/WCDMA the concept is to renounce to the output isolator. In this case if the VSWR is high, and due to load-pull of the PA, the ACPR test is possible to fail.