Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
VSWR voltage standing wave ration, that means the ratio between transmitted signal from source to the reflected signal from the load (antenna), ideal case is VSWR=1, but of course it's not exists in the real life so the good ratio swinging between 1.0 to 1.2, over 1.5 is bad. as signal amplitude (voltage) is a proportion of impedenace (we talk about AC not DC so it's impedeance not resistance)
so VSWR equals to ration between load impedance and transmit media impedance, any differnce will cause high VSWR,
ex: transmission line with impedance 50 ohm (regular coax) should connected to antenna of 50 ohm impedance
i hope that i give you usefull information
thanks
Shafee
VSWR also gives idea how good the load receives the energy from the generator. When VSWR is close to 1 - almost all the energy from the generator is delivered to the load (radiated from the antenna). If VSWR is higher - 3, 4 and more, the most of RF energy will be reflected from the load input, back to the generator (like from mirror). Intereference in the transmission line between incident and reflected waves is VSWR.
Since the power delivered to the load in a transmission line , excited by a source with impedance Z0 is given by \[P_L=P_{AVS}(1-|\Gamma_0|^2)\] ,
so it follows that the magnitude of the load reflection coefficient , \[|\Gamma_0|
\] (which is related to the VSWR), provides a measure of what portion of
\[P_{AVS}\] is delivered to the load .
Now in an antenna \[P_L\] is the power propagated by the antenna , and
\[P_{AVS}\] is the available source power connected to the input port of the antenna.
if you couldn't understand the formulas please notify me.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
