UWB ANTENNA ISSUE - how to measure this test item?

[cyai]

UWB ANTENNA ISSUE

Hi, everybody

The UWB antenna shall be measued S11, radiation patterns and antenna gain. The group delay is also an important test item. And how to measue this test item??

Thank in advance.

 

[biff44]

Re: UWB ANTENNA ISSUE

Seems to me you need to sweep the frequency, and at each frequency point measure angle[S21] Transmitted by your UWB antenna and received by a known standard antenna. Then you can calculate group delay by ΔΦ/ΔF.

The problem is that you are using free space radiation, and there are long cable lengths, a chamber, and the receiving antenna to calibrate out. All "calibrated" standard antennas that I have seen have amplitude, but no phase, calibration data.

I know there is a "3 antenna" method of calibrating amplitude of similar unknown antennas. Maybe (and I am just winging it here) a "3 antenna" calibration could be done for phase. Once you have calibrated out the phase shifts in your test setup, you substitute the UWB antenna in for the final test.

 

[kleinesmurf69]

Re: UWB ANTENNA ISSUE

hello,

does the group delay vary with elevation or azimuth?


thanks

best regards

 

[Lupin]

Re: UWB ANTENNA ISSUE

Can we conlude that the most important parameters in the design of an UWB antenna are:
- Gain; - matching; - polarization purity; - group delay?

What about the phase diagram?

I think it's quite hard to control all the parameters for so wide bands...

What do u think?

Regards

Lupin