Research And Design Of Compact Circularly Polarized Microstrip Antenna

With the rapid development of wireless communication technology, antenna has been used widely, which is an indispensable component to the wireless communication device. Antenna technology has a significant progress in the last decade. In order to adapt to the miniaturization requirement of the modern communication system, it becomes more and more important to reduce the related antennas.Some miniaturization techniques have been proposed by scholars in recent years, such as cutting slots on the patch, using high permittivity substrate and so on. To some extent, these methods will deteriorate the performance of antennas.Firstly, a compact antenna is proposed, which improves the performance of circular polarization to overcome the deficiency of cutting slots on the patch. The size of the antenna is reduced by cutting the diagonal slots on the square patch. Two pairs of asymmetric narrow slots have been loaded into the ground plane for circularly polarized. An additional rhombic slot has been loaded into the center of the ground plane to achieve the circularly polarized performance of easy tuning.Then, a circularly polarized microstrip antenna with bandwidth broadening is proposed, which aims at the problem of narrow bandwidth by using high permittivity substrate. Coaxial feeding loaded microstrip matching section is used to achieve impedance matching. The impedance and axial ratio bandwidths are improved by placing four sequentially rotated split-ring resonators around the patch of the antenna and embedding a defeated ground structure on the center of the ground plane. Experimental results show that that the impedance and axial ratio bandwidths of the antenna are increased by 68.2% and 56.6%, respectively.