EFFECT OF PLACING PARASITIC DIRECTORS IN MICROSTRIP PATCH ANTENNA FOR IMPROVED BANDWIDTH AND DIRECTIVITY

摘要

A planar Microstrip Yagi array antenna is proposed that can achieve a Ultra Wide bandwidth for various wireless applications. The proposed antenna array is designed at the frequency of 4.8 GHz. Ultra Wide bandwidth is obtained by resonating the patch, C-shaped reflector and directors at the closest valu. The significance of this proposed antenna is placing reflectors and directors in the design of Microstrip antenna in order to achieve cost effective, miniaturized Microstrip Yagi array antenna structure. The length of the director element is always less than A/2. A parametric analysis is provided to find the appropriate position of driven elements from the radiating patch. This is accomplished by varying the spacing between them. Henee the directivity of the proposed antenna is considerably increased. Through the simulation the reflection coeficient is obtained for the proposed antenna design s -30.28 . An impedance bandwidth of 22% can be achieved at the resonance frequencies. In simulation the directivity is obtained as lOdBi and VSWR is obtained as 1.04. In the fabricated model the size reduction is achieved as 12%.Performance comparison table for various parameters is provided for different antenna designs. Measured results are found to be in agreement with simulated results.