RF-Performance Analysis of Reconfigurable Antennas with RF-Switches in the Far-Field

摘要

Reconfigurable antennas employing two most general RF switching devices (PIN diode and RF-MEMS switch) are presented for the comparison of RF performances in the far-field condition. Two types of antennas (monopole and slot) representing general direct/coupled feed types are used for the reconfigurable antennas to compare the excited RF power effect to the RF switches by reconfigurable antenna types. For the switching operation of antennas, biasing circuit is designed and embedded in the same antenna board including battery to emphasize the adaptability to mobile devices. The measurement results of each reconfigurable antenna performances (radiation patterns and return losses) are provided. The received power of the reference antenna was measured varying the transmitting power of the reconfigurable antennas at a distance of 2.5-meter, far-field condition. The received power is analyzed using the "Friis transmission equation" and compared for two switching elements. The relation between the transmitted and the received power is also examined to check the received power level and linearity of the reconfigurable antennas. Based on these measurement and comparison results, we discuss the proper choice of switch device and antenna type for the reconfigurable antenna in mobile devices of the far-field condition.