Single-Ended and Differential S-Parameters
Differential circuits have been important incommunication systems for many years. In the past,differential communication circuits operated at lowfrequencies, where they could be designed andanalyzed using lumped-element models andtechniques. With the frequency of operationincreasing beyond 1GHz, and above 1Gbps fordigital communications, this lumped-elementapproach is no longer valid, because the physicalsize of the circuit approaches the size of awavelength.Distributed models and analysis techniques are nowused instead of lumped-element techniques.Scattering parameters, or S-parameters, have beendeveloped for this purpose [1]. These S-parametersare defined for single-ended networks. S-parameterscan be used to describe differential networks, but astrict definition was not developed until Bockelmanand others addressed this issue [2]. Bockelman’swork also included a study on how to adapt single-ended S-parameters for use with differential circuits[2]. This adaptation, called “mixed-mode S-parameters,” addresses differential and common-mode operation, as well as the conversion betweenthe two modes of operation.This application note will explain the use of single-ended and mixed-mode S-parameters, and the basicconcepts of microwave measurement calibration.
使用pso求最小化一函數
matlab程式碼,寫的非常簡潔(不到100行),且還包括了2維的圖形展示,和大家分享參考!!!
一起學習matlab和各種optimize methods
最小化:(x-15)^2+(y-20)^2
The swarm matrix is
swarm(index, [location, velocity, best position, best value], [x, y components or the value component])
Author: Wesam ELSHAMY (wesamelshamy@yahoo.com) MSc Student, Electrical Enginering Dept., Faculty of Engineering Cairo University, Egypt