Monopole Fed by Microstrip in CST

Hi there,

can anyone advise me on how to simulate a simple FM monopole printed on a piece of Mylar fed by a microstip line in C/S/T M/w/s? How should the feed to the microstrip be modelled? Do I have to model a coaxial feed or is there a easier way out of this? Any advise will be very much appreciated.

(Attached Geometry in M/S W/o/r/d/s.doc)

Cheers,
Element7k

From your drawing it is unclear where your microstrip feed goes to?
Where is the microstrip fed from?

What you usually do is add an additional piece of microstrip or coax transmission line in that way that it does not couple to the antenna.
Then add a waveguide port at the end of the feed line and offset the reference plane of the port to be where the feed-line ends.

Hi, Element7k!

Also think it isn't very clear. Please can you attach according MWS file?
Eirp

I am trying to shift the feeding point to a point 150mm into the mylar (using the microstrip as a electromagnetically coupled stripline feed). I still have not worked out the geomentry of the microstrip for a 50 ohm match but here is a quick attachment in CST. The problem is how do I feed this microstrip in CST with the gnd plane at a distance behind the antenna?

Thanx.
Element7k

Someone offered me this solution so I thought I will post it up here.

hello,element7k,
I simulated a quarter wavelength monopole vertically placed on a infinit ground plane using CST 4MWS,opting the discrete port,template was antenna(with ground plane) ,other parameters such as mesh properties as same as the dipole that is given in CST examples,but I were surprised to find the directivity of monopole was 5.3dB on the phi plane,I don't kown where the fault is ,As an CST expert,Can you tell me how to simulate the monopole ?hope your reply!

Hi Beiga,

Reply in your query on monopole simulation on infinte gnd plane. I'm not C/S/T expert but will be glad to help whenever possible. :D

Cheers,
Element7k

hello,element7k,
I simulated a quarter wavelength monopole vertically placed on a infinit ground plane using CST 4MWS,opting the discrete port,template was antenna(with ground plane) ,other parameters such as mesh properties as same as the dipole that is given in CST examples,but I were surprised to find the directivity of monopole was 5.3dB on the phi plane,I don't kown where the fault is ,As an CST expert,Can you tell me how to simulate the monopole ?hope your reply!