On Thu, Sep 1, 2022 at 08:59 AM, Brian Howie GM4DIJ wrote:
The dielectric constant you chose might differ from the real one depending on
the material.
Many microwave materials publish TWO dielectric constant values; one which is used in standardized QC tests, and another one, the "design" value, which should be used for simluation. Be certain that you are using the correct one, the simulation tool will happily spit out beautiful, inaccurate plots.
Also, how are you decoupling the antenna from the measurement instruments? Do they change as you move you hand along the feedline? If so, the feedline is not adequately decoupled.
How big is your ground plane, if any is used? Is it adequate? An antenna's environment can mage a big difference.
73, Don N2VGU
Donald S Brant Jr