Design of compact microstrip omnidirectional wideband monopole antenna

The modern microwave communication systems nowadays require wide bandwidth, high gain and small antenna size with the purpose of providing enhance the performance over a wide range of frequencies. This paper has been discussed about a newly proposed microstrip omnidirectional monopole antenna with defected ground plane. The miniaturized antenna dimension and the resonant frequency of the monopole structures are about 18.48 × 21.18 mm and 5.4 GHz respectively. In this proposed microstrip antenna, there are notches sequentially inserting with suitable sizes and position. Very good radiation and impedance characteristics have achieved by inserting the notches on two corners of the quasi-square radiating patch. The parameters frequency of the realized antenna impedance bandwidth has measured from 5.3 to 22.5 GHz for VSWR value is less than 1.5. Due to the use of the microstrip line feeding, increase in the gain 15.18 dB at 19.3 GHz and achieved -21.73 dB, 0.33 GHz return the loss and BW respectively. And also proposed slot antenna gain 4.41 dB, 1.95 dB for 5.4 GHz and 14.9 GHz frequency respectively. The VSWR has been achieved less than 1.5 for both without the slots, with slot and defected ground. We have presented and discussed the improvement process of the radiation properties, the impedance bandwidth and the gain for this proposed microstrip omnidirectional antenna.