Antenna for 13.56MHz ISM frequency band
Whatever antenna you make for this frequency with such small dimensions, the gain will be very low, and you will have problems to meet the link budget for given power.
Perheaps the best option is to use a meander monopole in spiral shape.
Thank you for your reply. I tried to use loop antenna with 7 turns and dimesion 80mm x 40mm the S11 parameter is -25dB, but the results are very poor. Attenuation is 80dB on 5m distance. This antenna generate strong magnetic field but very weak electic field. I want to try build one of the monopol antena type. And I can incerase the electrical lenght of antenna with coil. What do you think about it? Will it be better?
Could you describe more detailed what is: "meander monopole in spiral shape", please? I understand what is menader monopol, but i can't imagine what is spiral type.
