180 phase shift with half-wavelength transmission line

[wlcsp]

Dear all

Half-wavelength transmission line gives an 180 degree phase shift.
Suppose I want to model it with T-network consisting 2 equal inductors and 1 capacitor (grounded) in the middle.
How can I define the L and C values, say for 850 MHz.

Many thanks.

 

[biff44]

I would set the ratio of L to C to be: 50 = √(2L/C)

Then I would adjust the values so that the phase shift of S21 was 180 degrees.

 

[tony_lth]

With one stage, the LC should be 71.4nH/1pF/71.4nH, with Return loss -11dB at the input.
maybe you should use multi-stages to simulate it.

 

[wlcsp]

Hi Tony,

Thanks for the reply. How to calculate it?

With one stage, the LC should be 71.4nH/1pF/71.4nH, with Return loss -11dB at the input.
maybe you should use multi-stages to simulate it.

 

[tony_lth]

Build a LCL model in simulation software, and optimize for phase shift & VSWR etc.
You can also build multistages in simulation software to get better results.