AWR1843: Are Tx1 and Tx3 only for planar antennas?

Hi, thanks for your reply.

If you are right, Tx1 and Tx3 of AWR1843 are horizontal (XY axis), and Tx2 is vertical (Z axis).

Therefore, the angular resolution of Tx1 and Tx3 is not related to the angular resolution of Elevation.

That is correct. That is the case on the TI EVM. But you can change that in your design. 

Regards,

Vivek

Thank you for your reply.

As you said, in TI EVM, the Tx antenna seems to have a fixed role for Azimuth and Elevation, but can each transmitter be set for Azimuth and Elevation in our design?

(example)
Tx1 and Tx2: Azimuth
Tx3: Elevation

Also, if you can change each setting, please let me know where you can change the settings.

Hello Hiroyuki,

The usage of the antennas to provide  azimuth or elevation angular resolution is decided by the placement of the antennas on the board. On the EVM you can find teh TX2 is shifted up by half lamda. Hence it provides better resolution in the ellevation plan.

regards,
vivek

Thank you for your detailed explanation.

It doesn't mean that each transmitter is prepared exclusively for Azimuth and Elevation, but that it is divided for Azimuth and Elevation according to the design of the antenna itself.

If you want to see in both Azimuth and Elevation directions like AWR1843Boost, you have to shift up one of the antennas.

Therefore, if you want to identify the results measured by xWR on the xyz axis, you will need to shift up the Z axis and adjust the antenna spacing on the X axis.
(Is there a document published somewhere that the elevation resolution is improved by shifting the antenna up?)

Hello Hiroyuki,

You can refer to the basic FMCW radar training material that would help you understand how the angular resolution depends on the number of antennas:

https://training.ti.com/node/1139153

regards,
vivek

Hi, Thank you for providing the story with the placement of the antenna.

It is written about the difference in angular resolution due to the antenna spacing and FoV, and it is said that it is applied to Azimuth and Elevation, respectively.

The calculation of the angular resolution of Azimuth and Elevation is as follows.

(2/(Tx num)*(Rx num))*(180/π)

Azimuth
Tx num = 2, Rx num = 4

Elevation
Tx num = 2 (because the Z-axis direction of the Tx antenna is not shifted except for Tx2)
Rx num = 1 (since all Rx antennas are at the same height as the Z axis)

Reference material
tedspweb.teldevice.co.jp/.../1378

Thank you for your reply.

The question about angular resolution has been resolved.
I calculated the same value.

By the way, regarding FoV, it is 2*sin-1(λ/2d).
(Antenna spacing is d)

The elevation direction is ±15 deg, but the actual Boost is shifted by 0.5 λ in the z-axis direction. (see URL)
dev.ti.com/.../node

I would like to know why the values are different.

Hello Hiroyuki ,

The FOV formulae you have put above 2*sin-1(λ/2d) , is  related to unambiguous angle range. ie the range of angles where the measurement will not over lap. The FOV mentioned in the dev.ti.com/.../node is related to the antenna gain reduction across angle. As the angle increases, the antenna gain reduces.

regards,
vivek

Thank you for your reply.

Is it correct to understand that FoV is the range that can be measured directly from the antenna gain, not the formula I wrote?

Hi, thanks for your reply.

The FoV of AWR1843Boost is up to the angle where it is 6 dB down.

If you want to expand the range of 6 dB down, you will need to design the antenna.