12. Design of power splitter for ADS use record
Based on ADS2022
The reference book is Mr. Lu Yifeng's ADS RF circuit design and simulation study notes
Pre-tutorials:
01. New project of ADS use records
02. Import of ADS use records Import of various simulation models
03. Use of DC simulation controllers of ADS use records 04.
Use of S simulation controllers of ADS use records & elliptic low-pass filter design 05. Lumped parameter matching of ADS use records 06. Distributed parameter matching of ADS use records 07. Matching
Q value of ADS use records-broadband and narrowband 08. Low-pass filter design and optimization of ADS use records 09. Filter of ADS use records Automatic design 10. Design high and low impedance filters with ADS usage records (including layout simulation) 11. LNA design with ADS usage records
0. Design resources (ADS engineering)
Design of ADS Wilkinson power divider
1. Design indicators
Center frequency: 2.4GHZ
2. Schematic design
Create a new schematic diagram and name it SCH1:
Search in the toolbar and find Passive Circuit DG-Microstrip Circuits
to insert the board control MSUB, set the board as FR4 parameters, and the board thickness is 20mil:
Find the Wilkinson power divider below and insert:
Double-click the control to set the parameters, the set parameters are as follows:
F: Center frequency
DeltaF: Bandwidth
Z0: Transmission line impedance
Response Type: Response type (Chebyshev, general, etc. can be selected) N
: The number of power dividers, if you need a larger bandwidth, you may need a multi-level power divider to achieve, 0 means automatic setting (according to requirements) Rmax: The maximum return loss coefficient of the input terminal, the smaller the better the performance Wgap: The width of the Wilkinson power divider isolation resistance, if you use 0805 resistance, you can set it to 80mil, 0603 can be set to 60mil Delta as the fine-tuning coefficient, and the performance of the power divider can be fine-tuned by
adjusting
this
coefficient
After setting all the parameters, find the passive circuit option (passive circuit) in the design guide and
select the first passive circuit control window:
Find the design button in the design assistant and click:
After the design is completed, go deep into the circuit diagram to get the circuit diagram of the power splitter: Go back
to the main schematic diagram, insert the 50 ohm port: insert
the S simulation control, and set the parameters reasonably:
Click the simulation button to view the parameters, first check the S11 parameters, and find that the center frequency is too large: modify the delta of the
Wilkinson power divider, and keep checking Parameters, it is found that when Delta=30mil, the center frequency of S11 is 2.4Ghz, which is most suitable for this design:
查看S21、S31等参数，S21、S31几乎重合，表示系统的等分性能很好，输出约为-3db，符合等分理论：
查看S32参数，虽然中心频率不在2.4Ghz，但是在2.4G时隔离度较好：
此时也可以在无源电路设计的控制窗口找到无源电路仿真选项：
合理设置仿真参数后点击仿真，弹出窗口，窗口显示了设计的器件的各种性能，与之前原理图仿真的几乎一致：
上面的原理图只有功分器，我们还要手动添加前后一段的连接线，新建原理图，将之前的功分器、S参数仿真器、板材参数复制进去，并在前后添加一些：
再次进行仿真，依旧具有较好的性能：
3. Layout simulation
Select the layout and click to generate the circuit diagram:
Find the EM setting in the layout and create a new EM setting:
Find the plate option and create a new plate FR4:
Set related parameters (plate height, etc.):
Set the simulation frequency parameters below:
Set output (all generated frequencies are output):
Set output EMmodel:
The circuit board obtained by generating the layout before is as follows:
Delete the resistor and insert the port:
Go back to the EM setting and click the simulation:
After the simulation is completed, click the Symbol button in the EM setting:
Click the blue-green icon in the lower right corner;
set it as follows and click OK:
Get layout:
Create a new schematic diagram, name it co_simulation, insert the symbol just generated from the library:
Set the simulation properties of this diagram:
Add resistors and ports, and set the S parameter scanning to be consistent with layout simulation:
Perform simulation and observe the results:
Next, replace the resistors with actual 0805 resistors:
Run the simulation again, and find that the performance is even worse at this time:
