HFSS, changing port impedance changes convergence
时间：03-30
整理：3721RD
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Hi all,
Newbee, first post, and still learning the rules and etiquette of this place. Be easy, k.
Here's the synopsis: I'm running an HFSS driven terminal solution. The design is a spiral transformer--a single loop primary around a flat archemedean spiral of a few turns.
I've read in various places that specifying port impedance does not effect adaptive analysis, but have much evidence to the contrary. I ran my simulation with 50 Ohm Z_0 and it converged in 5 passes with something like 90,000 tets. Then I tried changing Z_0. I made it some thing like 0.01 - j360 Ohms. This didn't converge after 16 passes and generated 1B tets (billion).
I find this to be a trend in my simulation. The lower I make the output impedance (at least the real part) the more difficult the convergence. Just to add a few notes: the primary loop (where my port is located) is a perfect conductor with a ~10cm radius and the solution freq is ~150MHz. My motivation for selecting the output impedance (specifically to add capacitance) is to get the primary coil to resonate at a specific frequency (related to secondary coil, similar to Tesla coil operation).
Any insight is highly regarded. Let me know if I should provide more info with this query.
Regards,
Herman
Newbee, first post, and still learning the rules and etiquette of this place. Be easy, k.
Here's the synopsis: I'm running an HFSS driven terminal solution. The design is a spiral transformer--a single loop primary around a flat archemedean spiral of a few turns.
I've read in various places that specifying port impedance does not effect adaptive analysis, but have much evidence to the contrary. I ran my simulation with 50 Ohm Z_0 and it converged in 5 passes with something like 90,000 tets. Then I tried changing Z_0. I made it some thing like 0.01 - j360 Ohms. This didn't converge after 16 passes and generated 1B tets (billion).
I find this to be a trend in my simulation. The lower I make the output impedance (at least the real part) the more difficult the convergence. Just to add a few notes: the primary loop (where my port is located) is a perfect conductor with a ~10cm radius and the solution freq is ~150MHz. My motivation for selecting the output impedance (specifically to add capacitance) is to get the primary coil to resonate at a specific frequency (related to secondary coil, similar to Tesla coil operation).
Any insight is highly regarded. Let me know if I should provide more info with this query.
Regards,
Herman
could u attach your design?
thanks, for the interest. I'm having trouble uploading the .hfss file. Let me know if you're having trouble with file dl.
Note: using HFSS 64 bit version on Windows.