Working Principle

As shown in the diagram, circulators have three ports, and their working principle involves unidirectional signal transmission in the order of T→ANT→R. Signals will travel according to the specified direction, with minimal loss when transmitting from T→ANT, but higher reverse loss when transmitting from ANT→T. Similarly, during signal reception, there is minimal loss when transmitting from ANT→R and higher reverse loss when transmitting from R→ANT. The direction of the product can be customized for clockwise and counterclockwise operation. Circulators are commonly used in T/R components.

As shown in the diagram, the working principle of an isolator is based on the circulator’s three-port structure with the addition of a resistor at one port, converting it into two ports. When transmitting from T→ANT, there is minimal signal loss, while most of the signal returning from ANT is absorbed by the resistor, achieving the function of protecting the power amplifier. Similarly, it can be used for signal reception only. Isolators are commonly used in single-transmit or single-receive components.

As shown in the diagram, the working principle of the Dual-Junction Circulator involves integrating a circulator and an isolator into one unit. This design is an upgraded version of the circulator, and the signal path remains as T→ANT→R. The purpose of this integration is to address the issue of signal reflection when the signal is received at R from ANT. In the Dual-Junction Circulator, the signal reflected from R is directed back to the resistor for absorption, preventing the reflected signal from reaching the T port. This achieves both the unidirectional signal transmission function of the circulator and the protection of the power amplifier.

As shown in the diagram, the working principle of the Triple-Junction Circulator is an extension of the Dual-Junction Circulator. It integrates an isolator between T→ANT and adds a higher reverse loss and an additional resistor between R→T. This design significantly reduces the likelihood of damaging the power amplifier. The Triple-Junction Circulator can be customized based on specific frequency range, power, and size requirements.