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Recent content by buding

  1. buding

    industrial length for the microstrip transmission line

    Well, the only advantages of FR-4 is that it is cheap and it is good enpugh for RF circuits. Disadvantages are changing RF properties depending on vendor. Problem is that every vendor prepare the whole material itself. Compared with for example ROGERS materials, which are very stable despite...
  2. buding

    industrial length for the microstrip transmission line

    It is OK to manufacutre such a width. The only think you have to consider before you will order your PCB is what type of software did you use for optimization. If it wasn't any real 3D or at least 2.5D simulator so You have to expect that measured results compared with simulations will be more...
  3. buding

    Simulations on digital modulation

    ADS or Microwave Office should handle this.
  4. buding

    simple E/M question

    Well, You're right. There is nothing like B=uH+J. I was wrong. As I said it was long time ago. Current density is present in maxwell eqn.: rotH=dD/dt + J which says that variable electric field will cause magnetic field. B=uH is material eqn. and it can be written as: B=uH + M where M i...
  5. buding

    simple E/M question

    Hi! B=uH is just a simplified Maxwell eqn. In real, it should be written as B=J+uH (isn't it??? ). J is ommited in some discussions because it's not present or its influence is so small that it can be ommited to make calculation easier. If we additionally assume that B, H and J are all vectors...
  6. buding

    dielectric antenna

    The efficiency of your antenna will be very dependant on dielectric material. As You probably know most of dielectric materials are much more lossy then air. Also they are trying to keep electric field inside. So, if You want minimize the size of antenna with dielectric load, be carefull. You...
  7. buding

    S-Parameter Measurement with Network Analyzer

    Hi! Using 0Ohm as "thru" and "short" and 50Ohm as "load" will not help You with solving this problem. If You would like to do like this You would have to modify standard definitions in Your network analyzer. There is posibility to introduced "user kit&quot...
  8. buding

    Human body model, sw frequency range

    Hi! Try one more time. In the meny on the left side go to "our products" and then open "broshures". You can open the first one ( mws4.zip) : CST Microwave Studio. Ther You will find just a short note about the model in the middle of document. But trust me, I was on...
  9. buding

    RF ground planes layout

    Hi! It strongly depends on the design. Sometimes, when the board is very big, ground plane on top side is used to make the whole board more rigid. In this case groung vias are necessary and placing them is also very important. Buding.
  10. buding

    Day/evening coverage

    Hi! I would like to add one more point of view. Antenna used i such a device is always pointed, in some way, towards the ground. And, as everybody knows, it gathers the thermal noise from the ground. During the night situation is much better. To avoid such a problems You have to make good...
  11. buding

    Human body model, sw frequency range

    Hi! I'm not sure if this is what You want, but I saw such a model of human body for high frequencies simulations in CST microwave studio. It allows to analyze the impact of em waves on human body. Check : www.cst.de. Good luck. Buding.
  12. buding

    Calcul/measurement of coax impedance ?

    Hi! The most of cables nowdays are 50ohm or 75ohm. Just check the matching. Buding.
  13. buding

    Sonnet Suite: HF Electromagnetic Software...

    Hi! I had opportunity to work with SONNET few times. Very easy to learn, and userfriendly. Good procedures to make analysis faster and easier. Good accuracy. Possibility to place many metal layers ( i.e. MOMENTUM has only two metal layers ) Possibility to improve thick metal layers. many more...
  14. buding

    90 degree hybrid

    splits the signal, and output signals are shifted in phase with 90 degrees. Buding
  15. buding

    How to increase bandwidth in dual-band antenna??

    What kind of feed system do You use? Maybe it is possible to improve bandwidth by making better feed circuit.

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