Andres Mera

Fix S11 equation in the attenuator block

Use enum to identify the filter implementation

Bugfix: the control never reached QW notch filter

Fix meter suffix issue

Unfortunately, Qucs does not handle complex port impedances. -------- Original Message -------- On 18 Dec 2019, 10:48, El Filali wrote: Can the port impedance be changed from real value 50 ohm to complex value? If yes, please describe how to do that? Thanks Change port impedance to complex value Sent from sourceforge.net because you indicated interest in https://sourceforge.net/p/qucs/discussion/311050/ To unsubscribe from further messages, please visit https://sourceforge.net/auth/subscriptions...

Yes, this is correct. The X-parameters are used to model a nonlinear device and they can be measured with a NVNA [1]. Notice that you don't need X-parameters to design a PA, just a good model of your transistor and a robust HB engine. Give a try to the ADS if you can, it comes with a number of design templates for PA design. You'll learn a lot from them. Good luck! [1] https://www.keysight.com/en/pd-1381958/pna-x-nonlinear-vector-network-analyzer-nvna-options-510-514-518-and-520?nid=-32996.775208&cc=ES&lc=eng...

Notice that [1] includes a two-port matching example (page 573). Using equations 12.40a-12.41d (attached) you will find the reflection coefficients you have to show to your transistor so as to achieve maximum gain. Then, convert these reflection coefficients into impedances and design the input/output matching networks (Z0 to rho_S and rho_L to Z0). Notice that Qucs includes a tool for two-port matching (Tools->Matching Circuit, CTRL+6). You may check your results with that. You may also like to...

Hi, Perhaps Qucs is not suited for the design of real-world PAs since such problem requires more advanced simulation capabilities (a robust HB engine, a reliable simulation model of the RF transistor and a loadpull sweep). The schematic is missing. Please try to paste it into pastebin.com and send us the link. given the load impedance is equal to 50 Ohms, matching the input impedance depends only on S11, and we have to achieve rhoS = S11*. That's only true if the device is unilateral (i.e. S12 =...