AWRL1432：AWRL1432：天線設計

Hi,

There is no limitation for the distance between RX and TX section.

But ensure in your simulations that the coupling between RX and TX is not too high. 

Thanks for reply

Another question. The current design uses MIMO mode at the antenna end. Multiple antennas transmit in turns. However, during the test process, SIMO mode was used. In theory, the transmit power of a single TX and multiple TXs should be similar, but After the test, the TX transmit power of SIMO is nearly half dB less than that of MIMO, so I would like to know what is the cause, or if there is anything else that needs attention.

Hi,

This depends on which chirping mode you are using in MIMO. If you are using TDM (Time Division Multiplexing) then only one TX will be chirping at a time and thus you can see the power output of a single TX. If you are using BPM (Binary Phase Modulation) both the TXs will be chirping at the same time, and you can see the combined power of both TX.

Is there any recommended value for the coupling part or what is the coupling on the EVM board?

主要是因為原本如果只設定一隻tx做mimo系統會沒辦法正常運行，所以為了可以正常做動，把tx天線數一樣調成兩支但txenable事實上只開tx1

但這樣做會造成功率下降的問題，所以想確認這樣做是否正確，或是有什麼需要注意的

The RX-TX coupling value is recommended to be less than -35db. In EVM it is less than -45db.

In mmwave Studio you can enable both TXs and select TDM mode of operation where each TX antenna will chirp alternatively or select BPM mode where both TXs would chirp simultaneously.

Hi KS,

But the current situation is that in TDM mode, the number of tx antennas is adjusted to two, but txenable only turns on tx1. In this way, the power of a single Tx1 should be confirmed.
The main reason is to know whether this is correct. Ideally, the power should not be It will go down

Hi bo,

Yes, you are right. In TDM mode only one Tx will be enabled at a time, and you should be able to record the power output of one TX. Are you saying that when you are operating in TDM mode the power output you are seeing is double to that of a single one. 

Thanks,

Sreedeep