SPST switch for 5.7 GHz TMAA

[lazy_frog]

Hi guys, I am currently designing a spst switch using "bar63-02l" PIN diode and am unable to analyze what is wrong with my circuit , the dc blocking capacitor and rf chokes are put so that they allow and deny the RF signal respectively, and a dc bias of 1V and -1V is given (for it to work in ON and OFF state respectively). Need help in improving the circuit and suppressing the rf signal when pin diode is off.

 

[FvM]

10 dBm is 0.7 Vrms respectively 2 Vpp, more into open circuit. Can be hardly switched with only +/- 1 V control signal, neither fully on nor off.

 

[lazy_frog]

10 dBm is 0.7 Vrms respectively 2 Vpp, more into open circuit. Can be hardly switched with only +/- 1 V control signal, neither fully on nor off.

Should I increase the control signal and decrease the rf signal power?

 

[BigBoss]

This PIN Diode has up to 3 GHz Operating Frequency specification. Internal junction capacitance is higher than 0.5pF@5.7GHz (rough estimation).
So, it's not very appropriate choice for 5.7GHz.

 

[vfone]

Place the PIN diode in shunt configuration (cathode to the ground), remove L2 from the circuit and use another 5pF capacitor to go to Port 2. You get better attenuation in this configuration compared to series mode.
Use initially a tunable DC supply to bias the PIN diode, instead of a pulsed signal, to find which is the optimum DC range for the diode vs attenuation.
In this configuration looks like BAR63 works fine even at 5GHz.

 

[lazy_frog]

Hi guys, I am currently designing a spst switch using "bar64-02V" PIN diode and am unable to analyze what is wrong with my circuit , the dc blocking capacitor and rf chokes are put so that they allow and deny the RF signal respectively, and a dc bias of 1V and -1V is given (for it to work in ON and OFF state respectively). Need help in improving the circuit and suppressing the rf signal when pin diode is off.

Also is there anything wrong with the diode selection and feeling stuck at this point.

Also attaching the S11 and S12 plots for BAR64-02V with bias as 1V

And for -1V bias these are S11,S12:

The S11 and S12 are measured using this circuit:

 

[FvM]

Please refer to the suggestions made in your previous posts.

 

[lazy_frog]

Please refer to the suggestions made in your previous posts.

Tried them all and updated the circuit by using a better pin diode and also looked at changing the configuration of pin diode but nothing worked.

 

[vfone]

The circuit attached provides about 0 to 30dB attenuation for V1 from 0 to 2V.