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Just a guess... It all starts with a SPST? And then you progress in steps until you have DPDT?
So once you put together a mosfet circuit to do SPST, duplicate it to perform symmetrical action (SPDT), and duplicate again so you have DPDT?
It's not readily obvious where the SPST section begins and ends, and what the control signals do. I think the control signal both biases the transistor, and adds DC component to the incoming signal (which is AC coming from the left-hand).
As for the DPDT schematic, there's two overlapped wires in the center, creating a kind of cross-biasing. I suppose the purpose is to turn on the left side which turning off the right (and vice-versa). Perhaps the purpose is also to add a DC component in the signal path.
What is the shape of phase plot do you wish to achieve?
Do you believe the problem is a switching fault?
Or, that L & C values are incorrect?
Can you make a simple circuit that serves to illustrate the behavior you wish to achieve ? And after you make it work properly, use it as a model to pattern the entire project after?
Amount of phase shift is determined by resistance combined with L or C or LC values. It's hard to be sure which resistance plays the chief role in this, whether input resistance or output resistance. Does your simulation have one or the other or both? Are you using a standard value such as 50 ohms at each location? Should it be installed at both input and output?
I don't understand the simulation setup. What's connected to the ports P1 .. P4 in the #3 circuit. The DPDT switch is for X-band signals, I'd expect respective RF signal sources and loads, in case of doubt with 50 ohm matching.
X-band is 8 to 12 GHz. What's the idea of applying 1 MHz to 1 THz signal in the #4 phase plot?
I't seems like you are not understanding the concept of a switched phase shifter. The specified phase numbers are increments, total phase is irrelevant.
Having said this, I don't know if your simulation circuit is working according to specification. But very surely, your simulation setup is unable to check for.