15. Coupler design for ADS use records
Based on ADS2022
The reference book is Mr. Lu Yifeng's ADS RF circuit design and simulation study notes
前置教程：
01、ADS使用记录之新建工程
02、ADS使用记录之导入各类仿真模型导入
03、ADS使用记录之DC仿真控制器的使用
04、ADS使用记录之S仿真控制器的使用&椭圆低通滤波器设计
05、ADS使用记录之集总参数匹配
06、ADS使用记录之分布式参数匹配
07、ADS使用记录之匹配Q值-宽带与窄带
08、ADS使用记录之低通滤波器设计与优化
09、ADS使用记录之滤波器自动设计
10、ADS使用记录之设计高低阻抗滤波器（含版图仿真）
11、ADS使用记录之LNA设计
12、ADS使用记录之功分器设计
13、ADS使用记录之功率合成的失配仿真
14、ADS使用记录之功率放大器设计
0. Source file download
ADS coupler design source files
1. Design indicators
Microstrip branch coupler index:
Center frequency 2.4Ghz
Bandwidth: 100Mhz
2. Microstrip branch coupler schematic design
新建原理图，命名为coupler1：
在原理图左侧工具栏找到以下库：
插入微带线耦合器控件（第二行第一个）与板材参数设置控件：
修改板材参数选项，使其为Rogers4350B板材：
设置耦合器参数，使其符合设计指标：
F：中心频率
DeltaF：带宽
Z0：传输线阻抗
Response Type：响应类型（可选切比雪夫、一般等等）
N：功分器的级数，如果需要较大带宽可能需要多级功分器来实现，为0表示自动设置（根据要求）
Rmax：输入端最大的回波损耗系数，越小性能越好
C：等分系数，3db为2等分
Delta为微调系数，在可通过调整此系数微调器件性能
Add port Term and appropriate S-sweep parameters in the schematic diagram (1-port input, 2-port isolation, 3 and 4 ports are equally divided): after all parameters are set, find the passive circuit option (passive circuit) in the design guide: 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 and get the circuit diagram:
Go back to the main schematic diagram for simulation, and find that the resonance frequency is about 2.5Ghz, which needs to be fine-tuned:
Modify delta, then click Design Passive Circuit here, and then click Simulate, and gradually get the optimal solution after trying again and again:
Finally, it is found that the resonance is around 2.4Ghz when Delta=35mil, which meets the design requirements:
3. Microstrip branch coupler layout design
Click Layout and select the first generated layout:
The generated layout is as follows:
add a small piece of copper foil to all input ports, which is convenient for simulation to identify ports:
insert ports at all boundaries:
perform EM settings, first set the plate RO4350B:
its parameters are 3.66 and 0.0037:
set appropriate sweep parameters and sweep frequency range:
output all generated frequencies:
Model requires output EMmodel:
click to simulate, and the simulation is completed after a period of time. Click the SYMBOL option in the EM settings:
set the generator Source View to layout, and the generation option to Lookalike:
click OK to generate the following model:
4. Microstrip branch coupler layout co-simulation
The new schematic is named co_simulation, and the previously generated symbol is inserted:
Insert the port and set the S-parameter scanning control reasonably:
click the choose view for simulation button on the left side of the simulation button, click the generated layout symbol, and select emmodel: click 
OK to perform the simulation, and find that the frequency center is to the left, but the performance is not bad:
5. Microstrip weak coupler
The second row and second column of the previous passive circuit device column is the microstrip coupler. The design method is the same as above, so I won’t introduce it in detail here:
6. Stripline weak coupler
The stripline weak coupler often has better performance. The first one in the third line of the device column below is the design method as above, so I won’t introduce it in detail here:
