excitation dual mode with 90 degree phase difference using single probe feed for DRA

hi
im exciting dual mode with 90 degree phase difference using single probe feed for DRA, but dont know how make this 90 degree phase difference, could anybody help me?
thanks

If a capacitor is inline, and the waveform is a sine, then you'll get some amount of phase shift.

A coil will likewise introduce some amount of phase shift, depending on configuration, component value and frequency.

To get 90 degrees difference you may need a coil and a cap, or 2 stages with caps, or 2 stages with coils.

hi
i found that s parameter of our structure is a complex number then it has magnetud and phase , then or job is that choose center frequency in place that s parameter of our two modes have 90 degree phase difference