From RL plot, it can be seen that 7.2% (549 MHz) BW is achieved, which is 5% higher than that of the antenna without
DR loading. Two loops in the impedance locus are formed as shown in smith chart. One full loop and half portion of other
loop are inside the vswr=2 circle. Gain is 5.4dB and directivity is 5.41dBi for this structure. Rad. efficiency is -0.004697dB
means 99.89%, which is 7% higher than that of the antenna without DR loading. Phase center for center freq. 7.7GHz is
shown in Fig. 6. The phase center is the point from which the electromagnetic radiation spreads spherically outward, with
the phase of the signal being equal at any point on the sphere.