Effect of the shorting posts on short circuit microstrip antennas

Abstract

In many antenna applications, the size of the antenna is considered as an important factor in the design process. Therefore, short circuit microstrip antennas are widely used because the short circuit antenna can realize the same resonant frequency, at about half the size of the standard microstrip antenna. The shorted microstrip antenna is constructed by short-circuiting the zero potential plane of an ordinary microstrip antenna excited with a dominant mode. Physically, this short circuit may be complete, by wrapping a copper strip around the edge of the antenna, or it may be simulated by shorting posts. From the manufacturing point of view, construction of shorting posts is much easier than wrapping a copper strip around the edge of the antenna. In the present paper, the effect of such shorting posts on the performance of the microstrip antenna is studied experimentally. However, the effect of the shorting posts depends on different parameters like the number of the posts, the radius of each post and the thickness of the microstrip antenna which determines the length of the posts. The effect of each of these parameters is investigated and presented. >