hello everyone
quite new in this field so please have some patience with me
i have to design a dual band dipole antenna resonating at 13.5 MHz and 866 MHz with port impedance 13-13.5 (real) and 120-130(imaginary) parts with dimensions not greater than 40 by 40 mm2
i have designed some antennas in CST so familiar with the software.My big dilemma is how do i start this?Am i just choosing a random shape and work on it?or there is other way of planning it before implementing in CST?
As for the 13.5 MHz antenna, it's simply impossible. A antenna with the given size, either loop or dipole, will have a radiation resistance in the low milliohm range.
Are you actually designing a 13.5 MHz antenna? Or an inductive near-field coupler?
For 13.56 MHz, an inductive coupler (e.g. a printed coil with 5 or 10 windings) is the only reasonable way to implement the tag "antenna". For 886 MHz, a shortened dipole is feasible.