How to reduce the I and Q mismatch?

there is a amplitude mismatch of about 100mV.

the output is at 2.4 Ghz

how to reduce this amplitude mismatch

what is the reason once the circuit is symetical

I/Q Amplitude mismatch appear if:
- Unbalance in the RF splitter used to divide the incoming RF signal equally between the I and Q paths which may introduce gain differences.
- The quadrature 90° phase-splitter used to generate the I and Q Local-Oscillator (LO) signals that drive the I and Q channel mixers may not be exactly 90°. Furthermore, there might be differences in conversion losses between the output ports of the I and Q channel mixers.
- Amplitude mismatch appear also if the filters and ADCs in the I and Q paths are not perfectly matched.

Use 1% tolerant components in Both I and Q paths. If you dont have 1% components measure each component and put equal value components in both paths.

regards
GV

What kind of effects will result when I and Q are mismatch ?

HI,

mainly EVM degradation

If I and Q are mismatch, the image rejection will be reduce.
When amplitude mismatch increase 0.5dB the image rejection will reduce 5~10dB.

Hi,

please review the following paper!

David

"Unbalance in the RF splitter used to divide the incoming RF signal equally between the I and Q paths"
How does the RF splitter divide I and Q?

Hi,
For the RF splitter to split the data into I and Q channels, a clock should be used as one of the inputs to the RF splitter.
bye
Bhanumurthy.

Bhanu,
could you pls provide more details (datasheet) of this special RF splitter which splits into I and Q

Regards
GV

GVVIN,
The details abt the special RF splitter can be found in the text book"Principles of Communications-Fundamentals through Advanced" by Wayne Tomasi.
bye
Bhanumurthy