12. Design of power divider for ads usage record

12、ADS Use the recorded power divider design

be based on ADS2022

The reference books are Mr. Lu Yifeng's ADS RF circuit design and simulation learning notes

Pre tutorial ：
01、ADS New projects using records
02、ADS Import various simulation models using records
03、ADS Use of records DC Use of simulation controller
04、ADS Use of records S Use of simulation controller & Design of elliptic low-pass filter
05、ADS Use the lumped parameters of the record to match
06、ADS Distributed parameter matching using records
07、ADS Use record matching Q value - Broadband and narrowband
08、ADS Design and optimization of low pass filter using recording
09、ADS Automatic design of filters using records
10、ADS Design high and low impedance filters using recording （ Including layout simulation ）
11、ADS Use of records LNA Design

1、 Design indicators

center frequency ：2.4GHZ

2、 Schematic design

New schematic , Name it SCH1:

Search in the toolbar and find Passive Circuit DG-Microstrip Circuits

Insert sheet control MSUB, Set the sheet to FR4 Parameters of , Sheet thickness 20mil：

Find Wilkinson power divider below and insert ：

Double click the control to set parameters , The set parameters are as follows ：

F： center frequency
DeltaF： bandwidth
Z0： Transmission line impedance
Response Type： Response type （ Optional Chebyshev 、 Generally and so on ）
N： The number of stages of the power divider , If a large bandwidth is required, a multi-level power divider may be required to realize , by 0 Indicates automatic setting （ According to the requirements ）
Rmax： The maximum return loss coefficient at the input , The smaller, the better
Wgap： Width at the isolation resistance of Wilkinson power divider , If you use 0805 The resistance of can be set to 80mil,0603 Can be set to 60mil
Delta Is the trim factor , The performance of the power divider can be fine tuned by adjusting this coefficient

After all parameters are set design guide Find the passive circuit option in （passive circuit）

Select the first passive circuit control window ：

stay design assistant Find design Button and click ：

After the design is completed, go deep into the circuit diagram to check , Get the circuit diagram of the power divider ：


Return to the main schematic , Insert 50 Ohm port ：

Insert S Simulation control , Set the parameters reasonably ：

Click the simulation button , View parameters , First of all to see S11 Parameters , It is found that the center frequency is too high ：

For Wilkinson power divider delta Make changes , Keep checking parameters , Found in Delta=30mil when ,S11 The center frequency of is 2.4Ghz, Most suitable for this design ：

see S21、S31 Equal parameter ,S21、S31 Almost coincident , It indicates that the bisection performance of the system is very good , The output is about -3db, Conform to the bisection theory ：

see S32 Parameters , Although the central frequency is not 2.4Ghz, But in 2.4G The isolation is good ：

At this time, you can also find passive circuit simulation options in the control window of passive circuit design ：

After reasonably setting simulation parameters, click simulation , Pop-up window , The window shows the various performances of the designed device , It is almost consistent with the previous schematic simulation ：

The above schematic diagram only has power divider , We also need to manually add the front and rear connecting lines , New schematic , Put the previous power divider 、S Parameter simulator 、 Copy the plate parameters , And add some before and after ：

Do the simulation again , It still has good performance ：

3、 Layout simulation

Choose layout Click to generate the circuit diagram ：

Find in the layout EM Set and create EM Set up ：


Find sheet options , New sheet FR4：

Set related parameters （ Plate height, etc ）：

Next, set the simulation frequency parameters ：

Set output （ All generated frequencies are output ）：

Set output EMmodel：

The circuit board obtained from the previous layout is shown below ：

Remove the resistor and insert the port ：

go back to EM Set click simulation ：

After the simulation is completed EM Settings Click Symbol Button ：

Click the blue-green icon in the lower right corner ;

Set as follows and click ok ：

Get the layout ：

New schematic , Name it co_simulation, Insert the just generated... From the library symbol：

Set the simulation properties of this diagram ：

Add resistors and ports , Set up S Parameter scanning is consistent with layout simulation ：

Conduct simulation , Observations ：

Next, replace the resistance with the actual 0805 resistance ：

Do the simulation again , It is found that the performance is worse at this time ：