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ratio @ 2.45GHz
Return Loss (low band antenna) Coupling f om high band to low band antenna
0
-10
-20
I -30
O -40 « EBG
-50'i ^ No EBG
-60
2 3 4 5 6
Frequency [GHz]

Figure 5. Simulated return loss (RL) and coupling (Q of the dual-band CP antenna with and without
EBG structure. Simulated gain (G) and axial ratio (AR) of the dual-band CP antenna at 2.45 GHz with and
without EBG structure.

Radiation properties of the low band antenna at 2.45 GHz with and without EBG are also shown in
Figure 5. As expected, EBG lattice does not affect the gain or axial ratio of the studied antenna in the de-
sired operating frequency band. Similar results were found for the high band antenna.

CONCLUSIONS
A dual-band CP rectenna operating at 2.45 GHz and 5.8 GHz has been designed and evaluated. Success-
ful operation at both frequency bands was verified with measurements while rotating the rectenna relative
to the transmitter. A method for improving the harmonic rejection of the antenna was also studied. The
proposed EBG structure was found to be simple and effective solution that also resulted in decreased cou-
pling between the high band and low band antenna without affecting their radiation properties in the
operating frequency band.

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