Return loss

Discussion in 'The Projects Forum' started by rakeshm55, May 12, 2011.

  1. rakeshm55

    Thread Starter Member

    Oct 19, 2010
    In one of my application I need to determine an appropriate RF cable Assembly.
    My frequency of operation is 2.4Ghz.Characteristics impedance is 50Ohms.
    Cable length is 6 inch.

    I was suggested to use a cable set of frequency 0-3Ghz.
    Its characteristics impedence is 50 ohms .
    Max Operating Frequency:3 GHz
    Assembly Typ. Insertion Loss:0.55 dB (at 20°C, at 3 GHz))
    Assembly Typ. Return Loss:15 dB (at 3 GHz)

    Can i use this cable for my application??
    I am under the notion that 3db point corresponds to 3Ghz maximum operating frequency so there will be an amplitude reduction of 70%. Pls help
  2. SgtWookie


    Jul 17, 2007
    Basically, the lower the insertion loss, the better it is, and the higher the return loss, the better it is.

    The insertion loss is basically how much the signal is attenuated through the cable.
    The return loss is how much energy is reflected back from attempting to put a signal through the cable.

    A theoretically ideal cable would have 0.0 dB insertion loss, and > 100 dB return loss.

    The specifications that you have posted for the cable only show the 3GHz point, however, losses are generally higher at the high end of the frequency spectrum due to increased parasitics. It would likely work OK for your 2.4GHz application.