IWR1843BOOST: Corner Reflector, RCS question

RJimmy

Part Number: IWR1843BOOST

Hi TI,

In the document swra549, two corner reflectors are used to do test, the one for indoor measurement has RCS .86 m^2, and the other for outdoor measurement has RCS .11 m^2.

Q1: Are there any reasons to use small RCS for test?

Q2: What will be the issue that I use 100 m^2 RCS (big corner reflector) to do the similar test? I have one 2DFFT result which is from the indoor test. The radar board to the reflector is about 4.5m. The strongest peak is the reflector, and the noise floor is very noisy. Do you have idea what I did wrong for my test?

Thanks,

over 3 years ago

0 zigang Yang over 3 years ago

TI__Mastermind 32805 points

HI, Jimmy:

In the document you mentioned, we are trying to separate two target placed really close to show the range resolution. A bigger corner reflector has a much bigger size and will not be able to place so close.

Your corner reflector is quite big for a distance at 4.5m. You can only treat the corner reflector as point reflector if it is placed in the far field. You can check your corner reflector size and see what distance you should expect to see it as one clean peak.

https://www.everythingrf.com/rf-calculators/antenna-near-field-distance-calculator

Your figure also shows a reflection at 4.5m and then a lot of multiple reflections at 9m, 13.5m and etc. Which is also normal when you have a very strong reflector.

Best,

Zigang

0 RJimmy over 3 years ago in reply to zigang Yang

Intellectual 535 points

Hi Zigang,

Thanks for getting back to me so fast!!!

I have few more questions:

1) Normally, how do you judge the corner reflector is big or not based on the distance? So in my test situation, my big corner reflector is not a single point reflector for radar any more?

2) What do you mean multiple reflections at 9m, 13.5m and etc.? Does it mean the wave hit the reflector, and come back to the radar board, and reflect back to the corner reflector? And it happens for multiple times.

Looking forward to your answer.

Thanks,

0 zigang Yang over 3 years ago in reply to RJimmy

TI__Mastermind 32805 points

HI, Jimmy:

1) If you click on the link I send you, and input the size of your corner reflector, and RF frequency, it will tell you which distance is considered far field for this corner reflector. Only when the corner reflector is in its far field, can it be considered as point target. I tried a corner reflector of size 0.03m, and using the 77G as frequency, and it give me about 0.5 meters as far field range. That looks right to me.

2) You are right, the multiple reflection can happen, i.e., TX signal hit reflector, and come back to the radar board and reflect back to the corner reflector and etc.

Best,

Zigang