# WS6318 Maximum VSWR and dual-band compensation

**URL:** <https://forum.sierrawireless.com/t/ws6318-maximum-vswr-and-dual-band-compensation/7214>\
**Category:** Legacy AirPrime modules\
**Created:** [May 22, 2014, 7:58am UTC](https://forum.sierrawireless.com/t/ws6318-maximum-vswr-and-dual-band-compensation/7214 "2014-05-22T07:58:47Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![knifter](https://avatars.discourse-cdn.com/v4/letter/k/22d042/32.png) [@knifter](https://forum.sierrawireless.com/u/knifter)\
**Post date:** [May 22, 2014, 7:58am UTC](https://forum.sierrawireless.com/t/ws6318-maximum-vswr-and-dual-band-compensation/7214/1 "2014-05-22T07:58:47Z")

</div>

I’'m having trouble finding the right (and small, patch or fractal) antenna+compensation to use for dual-band usage of the WS6318 module.

The technical specifications of the WS6318 states that the maximum allowed VSWR is 1.5:1. However that is stated for the minimum voltage (of 3.2V) as a side-note.  
I’m using the 6318 because of size constraints. Therefore I would also need a small antenna. However, every antenna I have found so far has a VSWR \< 3. It would need compensation. But I’m using both frequency bands and compensating for both bands on one antenna proves rather difficult. Besides, after opening up various other GSM-based products I’ve found that they hardly use compensation or use a single compensation network for both bands.

- How would I go at this? Design a single compensation network? Or split up the frequency bands through various networks and (possibly) multiple antenna’s?
- What is the actual, full supply-range allowed VSWR?
- How would the module respond if I directly connect a VSWR \< 3 patch antenna? Would the module be damaged?
- How would one compensate for both the 900 and 1800 bands? Multiplex? Single network?

What did you do?

Thank you in advance,  
Tijs