[SOLVED] How to opt the shell parameters?

[tony_lth]

Hi, Gurus,
In one TI 77G desgins, it used the following as antennas: 3 TX , 4 RX.
And I simulated the 3 TX antenna's spec as the attachments.
The problem is the TX beamwidth is too samll.
I need to design a shell over all the antennas, the problem is I can opt the shell height over the board and shell thickness for the TX antenna.
Then I can opt the shell height over the board and shell thickness for the RX antenna.
The problem is that the two opt results will be different.
So how should I do? Tradeoff or some other ideas?
Best,
Tony Liu

 

[vfone]

Theoretically, the shell should be very thin and made from a material with low dielectric, to get minimum influence on the radar array pattern. Usually, the RX array may be more affected by the shell because is doing direction of arrival (DoA), when the TX antennas transmit boresight.
If the distance between antennas and the shell is greater than 2λ, there will be less influence on the array antennas (about 8mm at 77GHz).
Sometimes the radar module manufacturers provide the modules with shells in place.