New Design of Circular Microstrip Antenna Loaded by Two Annular Rings

This book is a theoretical study of circular microstrip antenna loaded by two annular rings (CMSAL2AR) and calculation of the contribution of the adjacent modes, studied positively or negatively affected on the antenna's coefficients (Bandwidth and Directive Gain). The proposed antenna is using the principle of equivalence with moment of method formulation of electromagnetic radiation to find the unknown electric current density on the conductor surface , and both unknowns, electric and magnetic density current on the dielectric surface which are responsible for the generation of far fields radiation in the space for the components (Eθ ,Eφ) . From the radiation pattern, it can be calculated with the contribution of the adjacent mode. The directive gain increased to (G= 19.92 dB) and bandwidth has been better (BW%= 19.9%) when this contribution is affected positively at the ratio Rab=5.5 and Rab=6.5 respectively.