Active Quasi-Circulator based on Wilkinson Power Divider For Miniaturized Wireless Communication System

Abstract

An active quasi-circulator based on Wilkinson power divider has been proposed and analyzed in this paper. A power divider, two common-source connected transmits and receive transistor amplifiers are used to consist of the circuit. The single conductivity of the transistor and the isolation of the power divider's isolation resistor are used to eliminate the interference between the received and transmitted signals, thus achieving the role of the quasi-circulator. The advantage of this circuit is that the received and transmitted electromagnetic signals can be amplified by two transistor amplifiers to a certain extent, which can save the design of additional signal power amplification circuits and improve the efficiency of circuit design. In order to verify the effectiveness of the proposed structure, an active quasi-circulator with a frequency band of 5GHz-6GHz is designed and the simulated structure is machined and fabricated. According to the measured results, in the frequency band of 5GHz-6GHz, the input return loss of antenna port is lower than − 10dB, the output return loss of transmit and receive ports are lower than − 15dB, and the degree of isolation between receive and transmit branches of the quasi-circulator is lower than − 18.6dB, which shows that the quasi-circulator has good working characteristics.