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About tomasbj

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  1. I thought this worked on: Downlink (Satellite to User Terminal): 10.7 GHz to 12.7 GHz Uplink (User Terminal to Satellite): 14.0 GHz to 14.5 GHz Considering that nowadays satellite constellations is a demanded topic, I think now this post is really useful. My questions below: 1) What are these cross patch shapes for? Directivity control, so that more gain? ... Surely the cross shape is for circular polarization achievement/improvement. 2) So... they use slot feeding mechanism?
  2. Awesome collection. Good job.
  3. HI mate. Do you have this model in CST? It is awesome! I would like to try to make it with Circular Pol. Thanks
  4. Two ports are well isolated because two orthogonal modes are being exited with this configuration. Bandwidth at S11 -10dB is reduced.
  5. Very simple and intersting performance. I guess Circular Pol will work well too by using two of these orthogonal oriented and 90º phase shift. I wonder how to make this much smaller. for the same frequency band.
  6. @Ukamurubasu, active S-parameters or F-parameters in CST are useful for phased arrays, or antenna systems in which one would like to quantify the coupling effect between both antennas. This is useful if and only if you use simulataneous excitation. Otherwise there is no sense to look at this active S-parameters. These are measured when the device under test (DUT), such as an antenna, is in an active state, i.e., it is powered and possibly transmitting. In this state, the antenna or network can exhibit different characteristics due to the influence of active elements like amplifiers or transistors. Active S-parameters are crucial for understanding the performance of the device under real-world operating conditions. They can provide insights into parameters like active input and output impedance, gain under active conditions, and the stability of the device when transmitting. This is very important in phased arrays, beamforming. The conventional S-parameters we use to work are called passive S-parameters. You get it! Added to this, calculate the reactive near field at the corresponding working frequency and check their separation distance on your satellite. So that if they are inside of the near field sphere, avoid it!. Because mutual coupling will be there.
  7. Very interesting. Thanks for sharing. Learning a lot in this forum.
  8. I agree. Really interesting, BTW
  9. How is the central part? are X-oriented and Y-oriented antennas touching each other?
  10. I see this antenna is connected to the reflector to the other side of the feeding. Why? and what is the difference between connecting it to ground or not at that end position. Thanks
  11. Could you please explain how the wire ends in this design? Apart, I understand the wire lenght should be lambda/2. Am I right? Do you have a .cst file to check the design? Thanks in advance for your help.
  12. Very interesting, Thanks for sharing! I was working with Rohacell Since it has very low relative permittivity and low tangent loss too.
  13. Very interesting model! Any generic rule for the design? thanks. I mean explanations.
  14. Very interesting Could you please share realized gain vs frequency? S11 too? I see you are exciting two orthogonal modes and breaking simetry with truncated corners and U-slot. What is the benefit of this? increase the bandwidth? Improve the axial ratio?
  15. Hi Guys, Why not one on top each other as gnss antennas. I mean, to make more compact this idea?