The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl Simulators >> RF Simulators >> Simulating load-pull and plotting output reflection at the same time https://designers-guide.org/forum/YaBB.pl?num=1263989873 Message started by DoYouLinux on Jan 20th, 2010, 4:17am |
Title: Simulating load-pull and plotting output reflection at the same time Post by DoYouLinux on Jan 20th, 2010, 4:17am Hi all, I am wondering about simulating a class A power amplifier in Cadence. In a documentation of doing load-pull test, it suggested that we can use a PortAdapter to plot constant power contours (in Gamma_L plane) and at the same time, we can plot input reflection coefficient (seen by input port) on this Gamma_L plane. By doing this we can compromise between max output power and input matching quality. However, what about output reflection seen by the 50-ohm load ??? From what I tried, after I designed an impedance transformation network to transform 50-ohm load to ZL,opt for maximum output power suggested by a load-pull test. After testing S22, its magnitude becomes high and the K factor is less than one around the operating frequency (S22 is about -3 dB). Is it possible to plot constant output power contours and at the same time, plotting output reflection seen by load, so that we can compromise between max. output power and matching quality at the load side ???? Thank you very much again, DYL |
Title: Re: Simulating load-pull and plotting output reflection at the same time Post by pancho_hideboo on Jan 20th, 2010, 4:59am I can't find out any design issue in your post. Your questions are no more than usage of very specific vendor's tool. Please post to Simulator's Board not Design's Board. DoYouLinux wrote on Jan 20th, 2010, 4:17am:
Is there truely a description of "By doing this we can compromise between max output power and input matching quality" in documentation ? DoYouLinux wrote on Jan 20th, 2010, 4:17am:
Here "PortAdapter" is not lossless. But if you use other tools such as Agilent ADSsim or GoldenGate, you can easily do. If you want to judge stability by K-factor under large signal operation, do LSSP or small signal S-parameter analysis subjected to master large signal steady state analysis with sweeping complex value impedance of ports. Again see http://www.designers-guide.org/Forum/YaBB.pl?num=1239997125 As another method, use interstage impedance probe with small signal analysis subjected to master large signal steady state analysis. This mehod can be applicable even in Cadence Spectre and "PortAdapter". http://www.designers-guide.org/Forum/YaBB.pl?num=1049348496 http://www.designers-guide.org/Forum/YaBB.pl?num=1218635777/5#5 http://www.designers-guide.org/Forum/YaBB.pl?num=1240334878/10#10 If your concenrs are stability in linear operation, SP-analysis or PSS/PSP analysis with Ocean function, lsb() might be useful for your purpose. Here "lsb()" is a function for Load Stability Circle. Note : Even if you use PSS/PSP, you can't consider nonlinear effects caused by complex load impedance, because steady state operation point is determined for fixed resistance value of port, e.g. 50Ohm. |
Title: Re: Simulating load-pull and plotting output reflection at the same time Post by DoYouLinux on Jan 23rd, 2010, 11:46pm Hi Pancho Hideboo, Thank you very much for your explanation. However, DoYouLinux wrote on Jan 20th, 2010, 4:17am:
Why is this not the "input reflection coefficient" of the PA ?? Thank you very much again, DYL |
Title: Re: Simulating load-pull and plotting output reflection at the same time Post by pancho_hideboo on Jan 24th, 2010, 3:04am DoYouLinux wrote on Jan 23rd, 2010, 11:46pm:
If you can understand "PortAdapter" correctly, answer is self evident. |
The Designer's Guide Community Forum » Powered by YaBB 2.2.2! YaBB © 2000-2008. All Rights Reserved. |