For the 3 dB lower marker, you can use the Y axis marker and scroll it down. In the property manager, you can also lock the marker line, and it automatically tells the f2 and f1 for the 3 dB drop.
Dear Dr. Remillard, First of all, I am grateful that you took the time of making these videos and posting them. I am a physics graduate student, and I cannot emphasize enough the values of these videos on my current research. For me, with not having a background in electronic engineering, this is the condensed knowledge I desperately needed. I would be thankful if you post a video about the theoretical calculation of the unloaded Q. I am currently studying a tunable cavity based on this coax resonator, which I will email you more details about it. Thank you again for your generosity, Geev
Thank you Geev for asking about this. Yes, I will make a video on the electromagnetic theory of Q (e.g. geometry factors and such) soon when I get a little time. In case it is also useful to you, here are some links to experimental Q measurement videos: Theory: ua-cam.com/video/TGbzYQlPFM4/v-deo.html Demo with a VNA: ua-cam.com/video/rb6oz3Pi4gA/v-deo.html Demo with only one port: ua-cam.com/video/5DgmH9XsfLA/v-deo.html But, I guess you might have already noticed those. Thank you for the request. Regards
Dear Dr. Remillard, Would that be possible to explain/show how one can measure the filling factor of a small region inside the cavity in hfss? Many thanks,
@@geevnahal7926 I suggest using Slater's theorem. First simulate without the dielectric present to get frequency fo. Then simulate again with the dielectric present and get frequency f. The frequency shift reveals the filling factor (ff). f^2=(fo^2)(1-ff) See Equation 10 in www.jpier.org/PIERB/pierb15/09.09041706.pdf. Be aware that this is perturbative. If the dielectric is a large part of the space, then this is not valid. But in that case, the concept of filling factor isn't so useful anyway.
Dear Dr.Remillard I am so grateful that you took the time of making these videos and posting them.I am a student who use the HFSS ,too. I am doing a cylindrical cavity simulation with HFSS, and its S11 is too low, just abot -0.1dB. Is it wrong for a simulation? The cavity is based on 2.45GHz, and I use probe to loop it. its diameter is 93mm and baout 80mm high.
Sorry I just saw this. Yes, you can do simulation at any value of S11 - even weaker than -0.1 dB. One advantage of resonator simulation is that you can inspect the resonance peak even when it is so weakly coupled that a network analyzer trace would be too noisy.
Thank you so much for the great video! Would you mind making a video on the analytical calculation of the Q_u and the field intensities inside the resonator? I appreciate it!
Amazing video. Can you please spare some time and make more HFSS simulation videos? Combining simulation results with analytical formulas is one of the very rare things and I have not seen it anywhere in the UA-cam video. Please benefit us from your knowledge.
I’m curious if you know of the limitations of HFSS for solving for the fields inside of a cavity in the overmoded case. Is there an expected limit for how overmoded I will be able to simulate?
Filter design and debugging (LC cavity microstrip waveguide bandpass, low-pass, high pass) duplexer design 10 years of experience in HFSS simulation design and engineering, with a design frequency of terahertz. All designs are based on practice and guided by theory. Remote after-sales service is available, and long-term cooperation can provide on-site service!
Dear Dr. Remillard, I have a question, may I know is there a function to slice/half cut the geometrical design, so that Im able to observe the signal propagation inside, I'm simulating a cylindrical cavity resonator ? Thank you in advance.
The short answer is yes. You can plot fields and currents on the Global xy, xz, and yz planes, and you can also define your own planes for observing the fields and currents. You can ask HFSS to animate the fields, which might give the representation of signal propagation that you are looking for. I don't have an active license right now, so I can't take you through doing that, but hopefully the content starting at 26:41 is at least a little bit helpful.
Hi Dr Remillard, i have simulated a cylindrical cavity resonator with a TE 011 mode at 8.5 GHz, when i placed a DR inside, the resonant frequency is increasing to 9 GHz, i am expecting to be lower than 8.5 GHz, do you know what had happened sir ?
You might be expecting the resonant frequency to be lower since it does decrease as dielectric constant increases. But this rule is for resonators of the same size and same field distribution. When the DR is placed in the cavity, the dielectric constant certainly goes up. But the TE011 mode is redefined and its shape is altered. My guess is that your result is because now a lot of the electric field energy is being constrained to a smaller volume (the dielectric), and the resonator configuration is not the same.
For the 3 dB lower marker, you can use the Y axis marker and scroll it down. In the property manager, you can also lock the marker line, and it automatically tells the f2 and f1 for the 3 dB drop.
Thank you Sudharsan Srinivasan for answering this question. Awesome! That takes out a tedious step.
Dear Dr. Remillard,
First of all, I am grateful that you took the time of making these videos and posting them. I am a physics graduate student, and I cannot emphasize enough the values of these videos on my current research. For me, with not having a background in electronic engineering, this is the condensed knowledge I desperately needed. I would be thankful if you post a video about the theoretical calculation of the unloaded Q. I am currently studying a tunable cavity based on this coax resonator, which I will email you more details about it.
Thank you again for your generosity,
Geev
Thank you Geev for asking about this. Yes, I will make a video on the electromagnetic theory of Q (e.g. geometry factors and such) soon when I get a little time.
In case it is also useful to you, here are some links to experimental Q measurement videos:
Theory: ua-cam.com/video/TGbzYQlPFM4/v-deo.html
Demo with a VNA: ua-cam.com/video/rb6oz3Pi4gA/v-deo.html
Demo with only one port: ua-cam.com/video/5DgmH9XsfLA/v-deo.html
But, I guess you might have already noticed those. Thank you for the request.
Regards
Done: ua-cam.com/video/NsKJ4YvzmR0/v-deo.html
@@stephenremillard1 many thanks,
Dear Dr. Remillard,
Would that be possible to explain/show how one can measure the filling factor of a small region inside the cavity in hfss?
Many thanks,
@@geevnahal7926 I suggest using Slater's theorem. First simulate without the dielectric present to get frequency fo. Then simulate again with the dielectric present and get frequency f. The frequency shift reveals the filling factor (ff). f^2=(fo^2)(1-ff)
See Equation 10 in www.jpier.org/PIERB/pierb15/09.09041706.pdf. Be aware that this is perturbative. If the dielectric is a large part of the space, then this is not valid. But in that case, the concept of filling factor isn't so useful anyway.
Fantastic video!
Dear Dr.Remillard
I am so grateful that you took the time of making these videos and posting them.I am a student who use the HFSS ,too. I am doing a cylindrical cavity simulation with HFSS, and its S11 is too low, just abot -0.1dB. Is it wrong for a simulation? The cavity is based on 2.45GHz, and I use probe to loop it. its diameter is 93mm and baout 80mm high.
Sorry I just saw this. Yes, you can do simulation at any value of S11 - even weaker than -0.1 dB. One advantage of resonator simulation is that you can inspect the resonance peak even when it is so weakly coupled that a network analyzer trace would be too noisy.
Thank you so much for the great video! Would you mind making a video on the analytical calculation of the Q_u and the field intensities inside the resonator? I appreciate it!
Yes, certainly. Here it is: ua-cam.com/video/NsKJ4YvzmR0/v-deo.html
Amazing video. Can you please spare some time and make more HFSS simulation videos? Combining simulation results with analytical formulas is one of the very rare things and I have not seen it anywhere in the UA-cam video. Please benefit us from your knowledge.
I’m curious if you know of the limitations of HFSS for solving for the fields inside of a cavity in the overmoded case. Is there an expected limit for how overmoded I will be able to simulate?
Filter design and debugging (LC cavity microstrip waveguide bandpass, low-pass, high pass) duplexer design
10 years of experience in HFSS simulation design and engineering, with a design frequency of terahertz. All designs are based on practice and guided by theory. Remote after-sales service is available, and long-term cooperation can provide on-site service!
Dear Dr. Remillard, I have a question, may I know is there a function to slice/half cut the geometrical design, so that Im able to observe the signal propagation inside, I'm simulating a cylindrical cavity resonator ? Thank you in advance.
The short answer is yes. You can plot fields and currents on the Global xy, xz, and yz planes, and you can also define your own planes for observing the fields and currents. You can ask HFSS to animate the fields, which might give the representation of signal propagation that you are looking for. I don't have an active license right now, so I can't take you through doing that, but hopefully the content starting at 26:41 is at least a little bit helpful.
Thank you sir for the reply, it is helpful. @@stephenremillard1
Hi Dr Remillard, i have simulated a cylindrical cavity resonator with a TE 011 mode at 8.5 GHz, when i placed a DR inside, the resonant frequency is increasing to 9 GHz, i am expecting to be lower than 8.5 GHz, do you know what had happened sir ?
You might be expecting the resonant frequency to be lower since it does decrease as dielectric constant increases. But this rule is for resonators of the same size and same field distribution. When the DR is placed in the cavity, the dielectric constant certainly goes up. But the TE011 mode is redefined and its shape is altered. My guess is that your result is because now a lot of the electric field energy is being constrained to a smaller volume (the dielectric), and the resonator configuration is not the same.
Is it possible to import geometry from SolidWorks to HFSS and use it together?
Yes it is. There are some videos uploaded by others demonstrating this. For example: ua-cam.com/video/ylfWOsuhBz4/v-deo.html