I need a reference circuit for 4_wire the impedance measurement using AD5934, range 50 to 250 ohm.

You may use this post as a starting point:

4 wire Impedance measurement

In the link, it is mentioned that setting Rcal = 20 can set the impedance range from 1 to 60. Can you please explain this, I did not get this. How can Rcal resistor set the range. 

https://ez.analog.com/dds/f/q-a/28201/ad5933-4-electrode-configuration-for-human-body-thoracic-impedance-measurement-0-60-ohm

I have another question,

Do I need any sort of filtering in the receiver end, before any amplification. 

Not sure if it is needed, does your application require galvanic decoupling of the impedance to be measured form the electronics?

It really depends on a particular use case - filtering is always tricky as it is not really known what to filter for unless the circuit is tested in real-life application and particular sources of interference are identified. The circuit itself in this 4-wire arrangement is reasonably resistant to environmental interference thanks to common-mode rejection. The high-frequency interference is likely to be sufficiently suppressed by relatively slow INAMP (250 KHz) and the AD5933 built-in 100 KHz low-pass filter.
What is the excitation frequency range you are planning to use? For impedance under test with capacitive response there might be a case for using an additional low-pass filter on the excitation side to filter out high-frequency spikes between the DAC steps in the synthesized voltage sine wave.

I got the desire signal. This is the signal I got on RFB resistor end. I will adjust amplifier gain to get the desire signal amplitude for AD5934's ADC.

Looks good, congrats!
Peak-to-peak voltage on this pin with PGA gain of 1x should  not exceed Vdd - 0.2V, and when PGA gain is set at 5x, (Vdd - 0.2V) / 5. This is likely to occur at the higher limit of your impedance under test. The little steps along the sine wave trace are the DAC steps from the frequency synthesizer I mentioned earlier.
The oscilloscope indicates signal frequency at  ~ 2.68 KHz, what is the clock frequency coming to the AD5934? Signal frequency might be potentially too low for the "DFT" to give accurate readings.

Snorlax said:

Looks good, congrats!

Thanks, your help was the main factor.

I will keep peak-to-peak voltage under the rated value.

Frequency is making troubles. Should I post my questions related to frequency and impedance measurement here or should I open a new issue?

I would just keep discussing it in this thread - forum moderators usually move questions to different groups/threads as they see fit, so the questions endup in the right place anyways.  

Ok, sounds great.

I follow the CN0349 design in which 1Mhz crystal is used. But now I noticed that, I can get around 7800Hz frequency (maximum) using 1Mhz crystal. Though, I can get higher frequency using sweep() function, but that one is also limited, I think max is 15KHz. For this part I already order 16Mhz crystal, so I will change the crystal. 

As you said.

"The oscilloscope indicates signal frequency at  ~ 2.68 KHz, what is the clock frequency coming to the AD5934? Signal frequency might be potentially too low for the "DFT" to give accurate readings".

I did calibrate my system with 100 Ohm resistor, with 100 Ohm resistor Vin was almost 1.09 V peak-to-peak. But when I measure 120 Ohm resistor I get impedance value 91. I check Vin for 120 Ohm, which was almost 1.2 V peak-to-peak.

Below is the print values for measuring 120 Ohm resistor.

Red 120 Ohm mean the actual value. 

My question is,

Is this because of low frequency or there can be some other issue?

Before getting into the weeds with the frequency, when you say Vin voltage, do you mean RFB voltage? From the screenshot we know the raw Re and Im  values, but what were  the raw Re and Im values when you connected the calibration resistor of 100 Ohms? Also, is the software that calculates the impedance something you wrote?  

Let me add the pictures of the waveform.

100Ohm 

120 ohm

AD9534 frequency is 5khz and sweep increment I set to 4 Hz. The acquired signal amplitude does changes but I get 91 Ohm when I place 120 Ohm resistor after calibration.  

After calibration with 100 ohm, when I do measure 100 ohm I get 100 ohm.

Let me add the pictures of the waveform.

100Ohm 

120 ohm

AD9534 frequency is 5khz and sweep increment I set to 4 Hz. The acquired signal amplitude does changes but I get 91 Ohm when I place 120 Ohm resistor after calibration.  

After calibration with 100 ohm, when I do measure 100 ohm I get 100 ohm.