Welcome to MagiMaji! (Magic Matching) This is a powerful online touchstone file viewer and simulator. Through any media such as windows PC, Linux, Apple MAC, Android, IOS and even higher-end VNA, as long as your media support the Internet and Dynamic HTML, you can quickly upload your S1P (or SNP if you have more port data) file and easily find out what is your result looks like. In addition, if you are intending to optimize the matching circuit network between the RF load and source. This tool has already equipped common passive components library and been ready for you to select and simulate the most possibly performance with the matching circuits fitted. Before you spend a lot of time to hand solder the components, why not just check the result here and save your time to do something more important...
1. Electrical Delay
Before upload the touchstone file (SnP). Make sure the file contains the correct electrical delay information. VNA are usually calibrated to the end of cable. However, in the real world measurement, for example, to measure the return loss of antenna, it is not likely I will be able to swirl the SMA connector of RF cable from VNA to the antenna feed. The most common approach is to utilize another intermediate such as coaxial cable or IPEX flexible cable to join the feed and its ground. The extra electrical length brought by intermediate cable will introduce a phase shift effect on simulated result. Technically, the extra electrical length changes the phase of signal while mean time keeps the same magnitude unless a very lossy intermediate is used to measure the result. The difference could be trivial in the dB/Frequency graph. However, if Smith Chart, simulating or optimizing matching circuit are preferable for the inspection during the testing, then the electrical delay is a critical parameter you cannot ignore.
How do I know if my electrical delay in the SnP file is correct? A simple way to find it out is that I can remove all of the components from the matching circuits. Once I did it and check the Smith Chart on my VNA then I should see a open which correspond to the Smith Chart should be a dot at the right edge of circle. So what I see on my VNA should be same as the right image below, if not I might need to adjust the electrical delay to fit it.
Wrong electrical delay
Correct electrical delay
2. Save and Upload
Once the electrical delay had been correctly set up, 0ohm resistors need to be put at the all series joints in the matching circuit to complete trace path, so that the VNA will be able to measure the DUT performance. Then save the S1P (Touchstone) file and upload it at the front page of MagiMaji. However, before rushing into playing the simulation and optimization, check if the Smith Chart on the browser looks identical as it is on the VNA. If not, this is because VNA such as several HP models only save electrical delay if the file was saved when the VNA were showing the result in Smith Chart format. And even some VNA such as Agilent E5071 doesn't save the electrical delay into S1P file, in such case it is necessary to manually apply the electrical delay after the file has uploaded.
After applying the correct electrical delay, simply select the component or input the keyword of the component preferable to use then simulate the performance of return loss with the matching circuit. Magimaji has already loaded several real common components data in advance. The result simulated should be similar to what it will measure on the VNA. But sometimes it won't fit the true result, this could be that the transmission on the PCB of the device is not 50 ohm or some other reasons.
After setting up the targeted bands, selecting the topology of matching circuits which are more preferable to fit it into the device. This optimization is a convenient function that help people to quickly find the values of components which could potentially be the optimal values for the device. It drastically saves the time from trying fitting components. Also, the simulated performance generated from the optimization could be an indication that the maximum potential performance, which could be used to decide if more try and error is necessary or just a waste of time.Try & Practice on sample file!
MagiMajji is currently using Murata GRM155 series for capacitor and LQG155 series for inductor. If you need the specific part number, please contact the developer through the email.