Type: Posts; User: vfone

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  1. Closed: Re: Please what is the maximum speed of a user at which 1. GSM can perform and 2.CDMA

    I think there is a confusion between speed (velocity) of a mobile phone (affected by the Doppler phenomenon) and speed of data (throughput).
    Those two things have totally different meanings..
  2. Replies

    Closed: Re: The difference between IIP3 and P1dB

    Theoretically, in a real life, P1dB is more important than IP3, because IP3 value is an imaginary point (never reached) that indicates when the amplitude of the 3rd order products equals the input...
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    Closed: Re: 750 MHz Band Attenuation Filter

    Any lumped component Band Pass Filter with central frequency greater than about 500MHz would be very sensitive to component tolerances, to PCB layout, and especially to temperature variations.
  4. Closed: Re: Please what is the maximum speed of a user at which 1. GSM can perform and 2.CDMA

    Both, GSM and WCDMA should support speeds up to 250 km/h.
  5. Closed: Re: Difference of Incident field>>scattered field>>total field
  6. Closed: Re: what is 'Phi' and 'Theta' angle in far field

    Spherical coordinate system used to plot radiation patterns
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    Closed: Re: MAR8 prior to AD8307

    This one is 20 bucks, it has a digital display, and is working unbelievable well:
  8. Replies

    Closed: Re: Wireless rectenna on flexible board

    On this Johanson webpage is a lot of information how to tune this kind of antenna:

    You have to re-design the PCB and get space for 3 matching components (Pi...
  9. Replies

    Closed: Re: Wireless rectenna on flexible board

    Your calculation of the new 50 ohms transmission line is good (from FR4 to Polyimide).
    The only thing that I see is that you don't have any impedance matching components for the Johanson antenna....
  10. Replies

    Closed: Re: Simple 50R I/O RF attenuator (1-30MHz)

    I didn't say that you have to include 50 ohms shunt resistors.
    The attenuators should have 50 ohms input/output impedance (Zo).
    Here you can find few options how to design these attenuators, and...
  11. Replies

    Closed: Re: Simple 50R I/O RF attenuator (1-30MHz)

    volker, no problem. I was sure that was a misunderstanding.

    neazoi, your circuit in post #6 will not do the job, because the overall input and output return loss of the group is not very good....
  12. Replies

    Closed: Re: Simple 50R I/O RF attenuator (1-30MHz)

    Your idea it will work somehow, and the explanation is this:
    A 10dB attenuator will have the input return loss (S11) better than -20dB whatever the output terminated impedance is (anywhere between...
  13. Replies

    Closed: Re: AD9851 what is the output level?

    Yes, the output level of the AD9851 is just below 0dBm with few dB. You need an amplifier which will provide also the necessary output impedance.
  14. Closed: Re: Is needed impedance matching for mixer diodes?

    Matching, if is well done and tuned, will decrease the insertion loss of the mixer.
    If is not designed well the mixer may have higher insertion loss compared with no matching at all.
    The matching...
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    Closed: Re: Functionl Generator 600 MHz

    The AWG presented in the link below, perhaps is the only device on the market that goes up to 600MHz. Usually the AWG generators sold by the big manufacturers goes only up to 120MHz.
    In the link is...
  16. Closed: Re: Power handling capacity of mobile phones,small satellite subsytem andwind profier

    <50W if the Radar receiver do not use continually rotating antenna (mechanical).
  17. Closed: Re: Trying to understand mismatched antenna behaviour above 20GHz without equipment.

    For sure is about the response of a transmission mentioned, you don't have lengths greater than 10cm.
    Sometime a simple impedance matching at TL ends (using distributed elements) would...
  18. Closed: Re: Regarding 5G antenna types & design guideline if any!

    Mobile device 5G antenna specification? There is no clear antenna specification not even for 4G, 3G or 2G mobile phones.
    Sometime is mentioned the OTA test (over the air) that have to pass,...
  19. Closed: Re: Doubts regarding MMIC LNA design usingKeysight Technolo Advanced Design System (

    At some universities this learning is a two year master degree process..
    During centuries there is a long list of self-taught scientists (da Vinci, Edison, Tesla, Heaviside, etc.) but is very hard...
  20. Replies

    Closed: Re: Basic question on cassegrain antenna

    I am not an expert on this domain but from what I heard, gold plated aluminum is the choice for high frequency Cassegrain reflector antennas.
    Most manufacturers don't specify this, they mention just...
  21. Closed: Re: Can you plot loadpull contour plots from impedance values ?

    I think you can plot the SWR circle, and not the return loss.
  22. Closed: Re: Deviation between simulation and measurement of matching circuits

    You just answered yourself to your initial question...
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    Closed: Re: Dual frequency matching

    The impedance matching network could be either single-band or wide-band.
    The antenna could be designed to get good VSWR for single-band, for dual-band (or multiple bands), or for wideband.

    If you...
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    [SOLVED]Closed: Re: Ingress in coaxial at FM frequency

    I think your definition "ingress effect" can be given by the "shielding effectiveness" which is a characteristic mentioned in most of the (good) coax cables data sheets.
    For example the double...
  25. Closed: Re: NFC System with antenna which can provide from 1 A/m to 7.5 A/m signal strength

    The transmitter output power of the S4100 module is 200mW. To get more signal strength you need to use an external power amplifier. I assume couple of watts (maybe less) will provide your desired...
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