@JLCPCB An RF branch line coupler is a four-port passive device commonly used in microwave circuits that splits an input signal into two output signals with a 90-degree phase shift. Typically implemented using a hybrid ring or branch line layout, it employs transmission lines with specific impedance (usually 50 ohms) to minimize signal loss. The coupler provides a defined coupling level, such as -3 dB for equal power distribution between output ports, and features isolated ports that prevent interference, crucial for maintaining signal integrity. These devices are widely used in applications like balanced amplifiers, signal combining, and generating differential signals, as well as in measurement setups where phase and power splitting is essential. Key performance metrics include insertion loss, return loss, and bandwidth, which dictate how effectively the coupler operates within a specified frequency range. In practice, engineers design or select branch line couplers based on their system’s frequency requirements, power handling capabilities, and the desired coupling factor to ensure optimal performance in their RF applications. #jlcpcb #electronics #engineer