Circuital Analysis of Coaxial Fed Rectangular and U-slot Patch Antenna

In this paper a coaxial fed microstrip rectangular patch antenna resonating at 2.45 GHz having a return loss of -23.05 db is proposed. Then a U-slot is etched into the patch to make it into dual band antenna. The U slot antenna resonates in the frequency band of 2-3 GHz having a return of -11.87 dB and -8.12 dB at 2.70 GHz and 3.81 GHz respectively. Then both antennas are then converted into their parallel RLC equivalent whose insight makes the complex analysis of RF harvesting system comparatively easier. The values of RLC circuit for the coaxial fed antenna are calculated as R = 13.30 ohm, L= 14.06 pH and C= 300 pF. While converting the U-slot antenna into its corresponding RLC, an additional inductor and capacitor are added in series with the original L and C of the RLC circuit. So multiple resonances occur in the circuit which explains that a single coaxial fed antenna is converted into dual band by etching U slot on it.