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Is phasor used for Electromagnetic waves, transient of RF module?

Posted 24 set 2013, 21:42 GMT-4 RF & Microwave Engineering, Parameters, Variables, & Functions Version 4.3b 2 Replies

Mengkai Liu
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After completing a simulation, I tried plot imag(temw.Ex) and actually got somthing. It seems that even in a transient analysis, the EM waves are still complex, not real. But actually the concept of phase is ill defined for a transient analysis because a wide range of frequencies exist. Also in the help documents, a phasor is said to be used for harmonic field, Electromagnetic waves, frequency domain. So what does a complex field mean in a transient analysis? This also gives rise to another problem. When I specify surface current by Jx=sigma*Ex, should I use real(sigma*temw.Ex) or simply sigma*temw.Ex? Also for a continuous wave source, should I use cos(omega*t) or exp(i*omega*t)?
2 Replies Last Post 1 ott 2013, 16:00 GMT-4
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago 25 set 2013, 08:27 GMT-4
Hi,

also a transient electromagnetic field can be seen as a composition of harmonic signals, each being a complex quantity. So the sum is of course also a complex quantity. It is just more difficult to assign a specific meaning to it.
What you do with the complex components depends on your application. For example in communication technology we use so-called I/Q demodulators to decompose an electronic signal into the real and complex components by multiplying sine and cosine functions to it. This facilitates further signal processing, such as complex FFT.

Cheers
Edgar

--
Edgar J. Kaiser
emPhys Physical Technology
Hi, also a transient electromagnetic field can be seen as a composition of harmonic signals, each being a complex quantity. So the sum is of course also a complex quantity. It is just more difficult to assign a specific meaning to it. What you do with the complex components depends on your application. For example in communication technology we use so-called I/Q demodulators to decompose an electronic signal into the real and complex components by multiplying sine and cosine functions to it. This facilitates further signal processing, such as complex FFT. Cheers Edgar -- Edgar J. Kaiser emPhys Physical Technology
Mengkai Liu
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Posted: 1 decade ago 1 ott 2013, 16:00 GMT-4
Got it. Thank you!
Got it. Thank you!

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