Abstract: In this paper a novel design approach of a probe feed circular microstrip patch antenna with four tuning arms on the radiation element for the dual-frequency operation is proposed. The cavity model is used for the parameter computation of the antenna. The circular antenna resonates at 4 GHz and 5.8 GHz which enables it to operate in standard C band which is used by communication satellites. TM110 is the dominant mode for this proposed antenna. The designed antenna provides 11 % bandwidth at 5.8 GHz (200 MHz) and the S[1 1] value is -42 dB whereas it provides 5.75 % bandwidth at 4 GHz (700 MHz) and the S[1 1] value is -16 dB. The absolute values of VSWR at 4 GHz is reported as 1.06 and at 5.8 Ghz is 0.08. A further modification is done on the proposed patch and a comparison of the designs are reported.
Keywords: Coaxial feed , circular microstrip patch antenna, C band , tuning arms, satellite communication.