IWR1443: Horn antenna / dielectric lens

Hello,
There is no planned application note on using horn to waveguide or lens for industrial mmWave sensors. The EVM has a > 90deg Field of View
as you have mentioned, this would find other objects like the tank walls. There are absorber/deflector materials that can help with EVM measurements. There are several technologies:

Circulator, Horn antenna - couples 1Tx, and 1Rx to a single Horn aperature
Patch antenna, Lens - couples 1Tx (and 4Rx), where Rx is beam formed, and lens further shapes the beam
There are examples of combinations of patch antenna, Horn antenna, and Lens also.

The array patch antenna, and dielectric lens has advantages of lower cost as long as the material being sensed in the tank and the RF reflected power can be detected with 'X' SNR after the 1st distance FFT. In some cases where lower Radar CrossSection (RCS) material or a larger tank is used, a higher gain RF antenna, may suggest a horn antenna, RF circulator .

If you are trying not to redesign the IWR1443 BOOST EVM, in the user guide, there is an antenna pattern for the patch antenna. The boresight antenna gain is ~9dbi. The non beam formed single Tx RF port output is 12dbm, allowing for 2db of loss, the antenna output would be 19db. You would have a di-electric lens designed (possibly you would design your own lens),
Given that you would use (1) Tx1, and (4) Rx in this manner, the Rx would collimate the radar energy with the Lens, to reduce the Field of View.

Example for 77Ghz radar using a dielectric lens - A High Efficiency Antenna with Horn and Lens
for 77 GHz Automotive Long Range Radar (from Proceedings of the 13th European Radar Conference)

Another approach, a mmwave sensor might have an RF circulator and a horn antenna. A single Tx and Rx RF port is connected to an RF circulator. The RF circulator may have a WR12 waveguide interface to couple to the horn antenna, rflambda.com/.../RW12HORN20C.pdf) The RF circulator provides a connection to a single Tx output, single Rx input port on the IWR1443.

This approach can have an antenna gain tailored to the desired RCS of the fluid or solid, and the distance.
Note: you could design a different style antenna than a patch for higher gain also.

The IWR1443 EVM, could have a custom lens. Here is an example, www.millitech.com/MMW-Antenna-GaussianOptical.htm
Although not for level sensing, there is a dicussion in this paper, cdn.intechweb.org/.../6894.pdf from the Braunschweig University of Technology Germany.

Regards,
Joe Quintal