What are the differences between even and odd modes of microstrip/coplanar waveguide?

[snkhan]

Hi
Can somebody explain what is difference between even and odd modes of microsrtrip/coplanar waveguide. What are the resonance mode of path antenna and how to determine them for a specific case. Any suggestion for reference or materials

Thanks

 

[flatulent]

coplanar waveguide odd and even mode difference

Even and odd are called common mode and differential mode in lower frequency circuit design.

 

[k.sridhar]

even and odd mode superposition

hi snkhan,

as i could remember even and modes any two parallel conductors or coplanar strips is that the modes when the current in the conductures flow in the same diration and opposite directions , it will be explained with parallel microstrip lines search for that

 

[snkhan]

Re: Even and odd modes

hi snkhan,

as i could remember even and modes any two parallel conductors or coplanar strips is that the modes when the current in the conductures flow in the same diration and opposite directions , it will be explained with parallel microstrip lines search for that

Thanks can u further refer some material in this regard

 

[tyassin]

Re: Even and odd modes

Hi

You can check out these books:

Microwave Engineering by David Pozar
RF & Microwave Coupled line circuits

Regards

 

[mfarhan1]

Re: Even and odd modes

normally even and odd modes are related in parallel line couplers.
If coupled lines are analysed at any instant, the relative polarities of voltages would be either same or opposite. They are named as even mode and odd mode propagation. The superposition of these two modes gives the overall behaviour.
even modes have equal phase in both lines and odd modes have opposite phase in both lines, this will change the EM field,

 

[jallem]

Even and odd modes

I do not think there are even/odd mode in
microstrip unless it is covered or somehow there
is another plane close by.
At difference to coplanar strip which will have both
mode of propagation.

 

[afz23]

Re: Even and odd modes

Even and odd mode are characteristics of parallel coupled transmission lines.

This concept Helps in realizing different coupling coefficients with coupled lines.

If both lines are at same polarity: even mode (Low impedance,Zoe)
If both lines have opposite polarity: odd mode(Higher impedance, Zoo)

Characteristic impedace,Zo=sqrt(ZoeZoo)=50 ohms(approx)
Coupling coeff,K=Zoo-Zoe/(Zoo+Zoe)

 

[snkhan]

Even and odd modes

Actually while discussing some collegue here told me that basides lobe in the radiation pattern also exists due to unequal ground size.

I was wondering unbalanced might possible with coaxial feed but unequal ground size.