i am new to dielectric resonator.. how to give excitation and feed for dielectric resoantor filter in hfss ..?
are you designing an antenna and want to excite the dielectric in between the conductors?
The answer is if you have already designed the resonator in HFSS, then you need to put "Ports" on both ends of the resonator in order to excite the resonator and obtain the frequency response in terms of S parameters.
Be it any EM simulator, HFSS, ADS, Momentum - you have to put ports for excitation.
There are two types of Ports in HFSS. Lumped Ports and Wave Ports. For your design, I am guessing Lumped Ports should be sufficient. A Lumped Port is a port that has a direct "wave" termination to the ground plane from the signal plane. By the wave I am referring to the quasi TEM electromagnetic wave which would exist assuming your resonator is microstrip, stripline or CPW.
Lumped Ports give the most accurate solution to the wave equation. You need to use a Wave Port only if your design geometry is complex and there is no direct access to the ground plane from the signal plane.
First you need to decide which mode you want to excite e.g for TM01d mode you can insert a probe in the center of the dielectric cylinder. Also microstrip feed can be used where fields are coupled to the cylinder from the microstrip line lying in close proximity of DR. And aperture coupling can also be used where aperture in the substrate material couples the energy in the DR
Thank you to all for ur valuable comments.. sir how we can determine which mode should exist and pass through the structure in HFSS..? there is any procedure is there pls comment on that topic.. and my another doubt is how to calculate the Q FACTOR in HFSS..
In the HFSS simulator, you can set the number of modes you want to excite (apart from the primary mode, which will be dependent on the geometry and type of port) before you run your simulation. This can be done in one of the tabs on the menu, I don't remember which one.
Remember that secondary and tertiary modes will only increase the simulation time and may not change the accuracy of the results much.
Before you can calculate Q factor, remember to enable Y parameter in HFSS before running the simulation. Then, once you have run the simulation, use the following formula in the plot window. However, remember that this is the "Single Port Unloaded Q", and therefore you will need to terminate the other port with 50 ohms (if you are using lumped port, the default impedance is 50 ohms).
Q = (Im(1/Y11))/(Re(1/Y11))
If you are unable to do this in HFSS, run the simulation, dump the snp file in ADS, and use the ADS plot window.
The only way to find unloaded Q factor is though Eigen mode simulation, In simulation setup you tell the simulator how many modes are you interested in. and also the start frequency of simulation. The simulator then computes the number of modes and tells you the frequencies and Q factors for each mode. But it can not tell you that the mode is TM01 or TE01 or hybrid etc you have to decide it by yourself by looking at the field plots. Therefore you have to be familiar with the field patterns for a specific mode and after visualizing the field you come to know which mode is at what frequency,.
Mr manish did you mean for example if am using microstrip line as a feeding method then i should assign two ports or what please can you elaborate more?
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